Article

Tabulated values of the Shockley–Queisser limit for single junction solar cells

Authors:
  • Applied Materials, Rehovot, Israel
To read the full-text of this research, you can request a copy directly from the author.

Abstract and Figures

The detailed balance limit for solar cells presented by Shockley and Queisser in 1961 describes the ultimate efficiency of an ideal p–n junction solar cell illuminated by a black body with a surface temperature of 6000 K. Today the AM 1.5G spectrum is the standard spectrum for non-concentrated photovoltaic conversion, taking light absorption and scattering in the atmosphere into account. New photovoltaic materials are investigated every day, but tabulated values to estimate their performance limits are difficult to find. Here values of the maximum short circuit current density (Jsc), open circuit voltage (Voc), light to electric power conversion efficiency (η) as well as current density (Jmpp) and voltage (Vmpp) at the maximum power point are presented as a function of the light absorbers’ band gap energy.
Content may be subject to copyright.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... In this work, it was found that reducing the defect density shows better output and leads to simulated efficiencies exceeding the Shockley-Queisser (S-Q) limit. For an absorber layer with a 1.9 eV bandgap, the S-Q limit is approximately 24.75 % [67], as shown in Fig. 20. Since achieving efficiencies beyond this theoretical limit is physically unrealistic, the results obtained from SCAPS-1D simulations-showing efficiencies higher than 24.75%-are not considered valid. ...
... S-Q limit for different band gaps[67].R. Ferdous and G. HashmiResults in Materials 25 (2025) 100665 Fig. 24. Here, three metal contacts, Ag (4.60 eV), Ni (5.15 eV), and Pt (5.65 eV) have been considered to understand the effect of the Schottky barrier. ...
... Finally, we provide perspectives for future research related to the quest for optimal inorganic LHP photovoltaic device efficiency and green energy. 3 . a Schematic overview of the typical ABX 3 crystal structure for halide perovskites. ...
... The miscibility of chloride in CsPbI 3 also faces the same issues. As a direct result, Cl cannot be incorporated into CsPbI 3 . It has been reported that the CsPbI 3-x Cl x majority phase only forms a mole fraction of approximately 2% 10 . ...
Article
Full-text available
All-inorganic lead halide perovskites (LHPs) and their use in optoelectronic devices have been widely explored because they are more thermally stable than their hybrid organic‒inorganic counterparts. However, the active perovskite phases of some inorganic LHPs are metastable at room temperature due to the critical structural tolerance factor. For example, black phase CsPbI 3 is easily transformed back to the nonperovskite yellow phase at ambient temperature. Much attention has been paid to improving the phase stabilities of inorganic LHPs, especially those with high solar cell efficiencies. Herein, we discussed the origin of phase stability for CsPbI 3 and the strategies used to stabilize the cubic (α) phase. We also assessed the CsPbI 3 black β/γ phases that are relatively stable at nearly room temperature. Furthermore, we determined the relationship between phase stabilization and defect passivation and reviewed the growing trend in solar cell efficiency based on black phase CsPbI 3 . Finally, we provide perspectives for future research related to the quest for optimum device efficiency and green energy.
... [1,2] Today, perovskite solar cells (PSCs) have achieved groundbreaking performances with a power conversion efficiency (PCE) of >26% − even outperforming silicon solar cells − via simple solutionprocessed device fabrication protocols. [3][4][5] Undoubtedly, this emerging materials class indeed shifts the paradigm in solar energy technologies, where the PSC will be a genuine solution for sustainable energy harvesting in the future. ...
Article
Full-text available
Controlling multiscale structural heterogeneities in halide perovskites (HPs) is a key bottleneck to achieving the reproducible high‐performances and longevity of perovskite solar cells (PSCs). A correlative understanding of structural and chemical features at the HP/charge transport layer interface is vital to realizing homogeneous and monolithic crystal matrices. Yet, this is not fully resolved as it requires holistic investigations of the multilayer systems. Herein, the intricate correlations of the interfacial features are resolved by utilizing chemically modified colloidal SnO2 nanoparticles (NPs) with ethylenediaminetetraacetic acid‐grafted polymeric chitosan (C‐EDTA). This chemical approach drastically enhances colloidal stability of the NPs, thereby manifesting a chemically homogenized surface of the electron transport layer. This promotes a homogeneous crystallization, refining the HP matrix while suppressing the evolution of pinholes and grain boundary grooves at the buried interface. This chemically and structurally refined heterointerface system significantly minimizes the interfacial charge recombination, thereby realizing improved performances of the PSCs with the highest power conversion efficiency of 25.12%. This work provides key insights into the role of structural refinement at the interface benefiting the performances and durability of PSCs − a vital principle in realizing sustainable solar energy platforms.
... Since PCE is directly related to the Jsc, Voc and FF according to the Eq. (9), P CE = JscVocFF Pin (9) where P in is the power of incident solar radiations 46 , increase in all the parameters ultimately results in improved PCE as confirmed by Fig. 2. ...
Article
Full-text available
From the time of discovery, CH3NH3SnI3 has been a promising candidate in photovoltaics due to its outstanding optoelectronic properties. However, stabilization was not easy to achieve in CH3NH3SnI3-based solar cells. Because CH3NH3SnI3 was used as an absorber, its naturally-occurring self-doping property spontaneously modified band alignment, which increased carrier recombination and decreased the efficiency of solar cell gradually. In this paper, for the first time, we have presented detailed study on use of CH3NH3SnI3 as a hole transport layer in prototype solar cell having configuration: CH3NH3SnI3/CZTS/CdS/ZnO/AZO, using SCAPS software. To understand the effect of spontaneous self-doping property of CH3NH3SnI3 on solar cell performance, the analysis of variation in solar cell performance parameters, band alignment conduction band, valance band, Fermi levels, charge density, current density, conductance, capacitance and recombination rate was performed as a function of increasing CH3NH3SnI3 carrier concentration. It was found that, when used as an hole transport layer, the inherent self-doping property of CH3NH3SnI3 became a helpful trait to increase hole extraction and spontaneously enhanced our device efficiency. Thus, the inherent self-doping property of CH3NH3SnI3 transformed from curse to boon when we leveraged CH3NH3SnI3 as an hole transport layer in our solar cell device.
... The record power conversion efficiency (PCE) for CdTe thin film solar cells has reached 23.1%. 1 However, this record PCE remains below the Shockley-Queisser limit, primarily due to the relatively low open-circuit voltage (V OC ). 2,3 Despite extensive efforts including doping CdTe absorber with group V elements and modifying the front or back interface, 4-6 a substantial improvement in V OC has not yet been achieved. ...
Article
Full-text available
Tin oxide (SnO2), known for its excellent optical and electronic properties, is increasingly favored as an electron transport layer(ETL) in high-efficiency thin film solar cells. However, its direct use in SnO2/CdTe heterojunction solar cells results in relatively low open-circuit voltage (VOC) and inferior power conversion efficiency (PCE). Herein, we achieve significantly high efficiency in CdTe-based photovoltaic devices by using Mg-doped SnO2 as ETLs, fabricated through magnetron co-sputtering technique. Capacitance–voltage (C–V) and space-charge-limited current measurements reveal that Mg doping significantly enhances the built-in potential at the SnO2/CdTe interface and reduces trap density over twofold. First-principles calculations indicate that the trap states originating from the Sn atom dangling bonds at the interface can be effectively passivated by the formation of MgSn defects, which are facilitated by Mg-doped SnO2. The resulting improvements in VOC and PCE are further validated through device simulations. This study demonstrates the potential of SnO2 as an ETL in high-efficiency CdTe solar cells and highlights the effectiveness of doping engineering in the contact layer for improving the interfacial properties of semiconductor devices.
... On the other hand, emerging photovoltaics develop clean and low-cost solar cells using organic and dye materials, even though their PCE and long-term stability are not eye-catching yet. Nowadays, the conspicuous growth of the PCE of organic-inorganic halide perovskite solar cells (OIHP) towards the Shockley-Queisser limit (33%), has astonished the photovoltaic research community [4]. Currently, OIHPSCs achieved a certified record PCE of 26.7%, making it on par with single crystal (non-concentrator) Si solar cells [5]. ...
Article
Full-text available
The noticeable growth in the power conversion efficiency of solution-processed organo-inorganic halide perovskite solar cells (OIHPSCs) incited the photovoltaic community to look for limitations that hurdle the commercialization process. The surface and interface defects between the perovskite and electron transport layers are among the main challenges that cause significant non-radiative recombination losses, thereby they result in poor performance and stability. In this work, tetracyanoquinodimethane (TCNQ), a strong electron acceptor molecule, is applied at the interface between the photoactive perovskite and [6,6]-phenyl C 61 butyric acid methyl ester (PCBM) layers to modify the interface, and enhance device performance and stability. Steady-state and time-resolved photoluminescence measurements were used to characterize the role of the TCNQ passivation in reducing non-radiative recombination of charge carriers. Current density versus voltage (J-V) measurements show improvement in devices open-circuit voltage (V oc ), short-circuit current density (J sc ), and fill factor (FF) for devices with TCNQ interface passivation, which is attributed to suppressed non-radiative recombination. In addition, a noticeable improvement in the device’s stability was observed. This study reveals the dual role of TCNQ passivation in improving the photoelectric properties and stability of ambient air processed perovskite devices with the pin architecture.
... A variety of Si solar cells are available in the market, such as PERC, PERL, IBC, and Topcon [10,11]. According to the Schottky-Queisser limit, a single-junction monocrystalline Si solar cell's maximum attainable theoretical power conversion efficiency is 33% [12]. So far, single-junction Si solar cells have achieved 27 [13]. ...
Article
Full-text available
PEDOT:PSS‐Si hybrid solar cell fabrication technique is highly cost‐effective, performed at low temperatures, and easy to fabricate compared to other solar cell fabrication techniques such as PERC, HJT, IBC, perovskite, and multijunction solar cells. In this experimental and theoretical investigation, we studied the effect of additive concentration on hybrid solar cell performance. We prepared PEDOT:PSS dispersion solutions with various weight percentages of DMSO (5 wt%, 7 wt%, 12 wt%, and 17 wt%) and 0.2 wt% of Triton X‐100. We used dimethyl sulfoxide as an additive and analyzed the variation in carrier concentration of PEDOT:PSS. Additionally, we examined the conductivity of PEDOT:PSS and the absorbance of the PEDOT:PSS layer. Hall effect measurement was used to determine the carrier concentration of PEDOT:PSS and Si. AFM analysis helped in understanding the polymer structure, distribution, and domain formation. We fabricated PEDOT:PSS‐Si hybrid cells using different weight percentages of DMSO. Solar cells with 7 wt% and 5 wt% of DMSO yielded 7.26% and 7.31% of power conversion efficiency, respectively. Numerical simulation was conducted using SCAPS 1D, and the obtained results aligned well with the experimental outcomes.
... When comparing the fabricated solar cells to the Shockley-Queisser (S-Q) limit, the increase in open-circuit voltage (Voc) follows the trend dictated by the optical bandgap [48]. Sample A2 exhibits the highest Voc at 1.25 V, which is consistent with its larger bandgap of 2.1 eV. ...
Article
Full-text available
This study presents the fabrication, characterization, and optimization of planar-heterojunction Cs₃Bi₂I₉ perovskite solar cells, supported by SCAPS-1D simulations. Experimental results reveal that among the fabricated devices (A1, A2, and A3), sample A3 demonstrates the highest efficiency, with a 0.72% improvement over its counterparts. This superior performance is attributed to its larger crystallite size, reduced strain, minimal dislocation density, and enhanced carrier mobility. These properties collectively minimize recombination losses, increase carrier lifetime, and improve charge transport and collection. To further understand and enhance the performance of the fabricated devices, SCAPS-1D was employed to simulate the model. By experimental parameters such as minority carrier lifetime and absorber layer thickness, the efficiency of the A3 device improved significantly in the simulated optimized model, achieving a notable increase in short-circuit current density (JSC). The optimization highlights the importance of balancing material properties and device architecture to minimize losses and enhance efficiency. This work also explores the relationship between carrier lifetime, diffusion length, and film thickness, emphasizing their combined impact on solar cell performance. While minor discrepancies were observed between experimental and simulated data, they fell within an acceptable range, validating the simulation approach. The findings underline the potential of targeted material and structural optimization to push the efficiency of Cs₃Bi₂I₉ solar cells closer to their theoretical limits. The success of sample A3 offers valuable insights for advancing perovskite photovoltaics.
... MASnI3-based cells does not exceed the limit [53]. The previous study also confirmed the achievability of these efficiencies as MAPbI3-based achieved a power conversion efficiency of 26.74% [54], and MASnI3-based cells achieved 27.43% [55] power conversion efficiency in the previous study. ...
Preprint
Full-text available
Perovskite solar cells are gaining popularity day by day due to the continuous effort of solar scientists. However, there are several barriers to the commercialization of this solar cell. Various materials can be used to achieve higher efficiency of perovskite solar cell design. Some of these materials may also contain lead (Pb), which harms human life and the environment. Another crucial hindrance for perovskite solar cells is the cost regarding hole transport material (HTM), electron transport material (ETM), and back contact; most of the common HTM, ETM, and back contact materials are expensive. In this study, we have chosen inexpensive HTM, ETM, and back contact to determine highly efficient and less expensive cell structures. Eleven non-toxic and three Pb-based absorber materials have been simulated using SCAPS-1D simulator where ETM (ZnO) and HTM (PEDOT: PSS+WO3) are constant to determine the best absorber material. Later the effect of thickness, temperature, back and front contact, electron affinity, defect density, and series resistance are also considered. After simulation and optimization, it is found that Ni is the least expensive back contact material for providing optimal efficiency, MAPbI3 is the best Pb-based absorber material with open circuit voltage (Voc) =1.10V, short circuit current (Jsc) =28.47 mA/cm2, fill factor (FF) =86.42%, power conversion efficiency (eta(%)) =27.10%. In contrast, the best non-toxic material is MASnI3 with Voc =0.97V, Jsc =34.89mA/cm2, FF =82.51% and eta (%) =27.98%.
... However, at 6% Cu-excess, a significant decrease in QFLS was observed, as illustrated in Figure 3D. Given that a higher bandgap contributes to the increase in the QFLS, [73][74][75][76] the non-radiative voltage loss is additionally presented in Figure 3D to facilitate a more accurate comparison of the optoelectronic quality of the absorbers. Figure 3D shows that the non-radiative voltage loss decreased from 386 mV in CR20 to 271 mV in CR07 and subsequently exhibited a slight increase to 287 mV in CR06. ...
Article
Full-text available
Cu(In, Ga)S2 demonstrates potential as a top cell material for tandem solar cells. However, achieving high efficiencies has been impeded by open‐circuit voltage (VOC) deficits arising from In‐rich and Ga‐rich composition segregation in the absorber layer. This study presents a significant improvement in the optoelectronic quality of Cu(In, Ga)S2 films through the mitigation of composition segregation in three‐stage co‐evaporated films. By elevating the substrate temperature during the first stage, the intermixing of In and Ga is promoted, leading to reduced Cu(In, Ga)S2 composition segregation. Furthermore, the optimization of Cu‐excess during the second stage minimizes non‐radiative voltage loss. These combined strategies yield quasi‐Fermi level splitting exceeding 1 eV and a record VOC of 981 mV in Cu(In, Ga)S2 devices. Consequently, a champion device achieves an in‐house power conversion efficiency (PCE) of 16.1% (active area) and a certified PCE of 14.8%, highlighting the potential of Cu(In, Ga)S2 as a stable and efficient top‐cell device for tandem photovoltaics.
... Photovoltaic (PV) systems are valued for their simplicity, scalability, and relatively low operational costs. However, their efficiency is fundamentally constrained by the spectral mismatch between the solar spectrum and the bandgap of the photovoltaic material, as defined by the Shockley-Queisser limit [2], which sets the theoretical maximum efficiency for singlejunction cells at approximately 33%. To address this limitation, multi-junction (tandem) solar cells were developed [3], which stack multiple layers of materials with different bandgaps to better capture the solar spectrum. ...
Article
Full-text available
Multilayer thin-film filters for beam-splitting applications were designed, fabricated, and characterized. Optimized 13- and 35-layer Nb2O5/SiO2{{\rm Nb}_2}{{\rm O}_5}/{{\rm SiO}_2} filters on K9 substrates achieved wideband transmission in the range of [580–1100 nm]. Optical and structural characterizations were performed using spectrometry, atomic force microscopy (AFM), and X-ray diffraction (XRD). The Nb2O5/SiO2/K9{{\rm Nb}_2}{{\rm O}_5}/{{\rm SiO}_2}/{\rm K}9 glass filter exhibited sensitivity to deposition conditions, especially in the very short wavelengths. Post-deposition annealing improved the filters’ morphology and optical performance, particularly in short wavelengths. Both filters demonstrated efficient performance with average transmittance values of 87.56% and 83.72%, respectively. Additionally, the highest reflectance and average reflectance in the remaining range were measured as 62.42% and 98%, respectively, making them suitable for hybrid photovoltaic thermal systems under optimized deposition and annealing conditions.
... [8][9][10][11][12][13][14][15] They share the same crystal structures as their lead-based counterparts and have ideal bandgaps (e.g., ∼1.4 eV for FASnI 3 , FA: formamidinium) for efficient single junction solar cells under AM 1.5G illumination. 16,17 Various strategies have been developed to enhance the performance of tin PSCs, including the purication of materials, 18-21 composition engineering, [22][23][24][25] and interface modication. 26,27 However, the maximum performance of Sn PSCs is still around 15%, 28,29 lower than that of their Pb counterparts. ...
Article
Full-text available
Although fullerene bisadducts are promising electron-transporting materials for tin halide perovskite solar cells, they are generally synthesized as a mixture of isomeric products that require a complicated separation process. Here, we introduce a phenylene-bridged bis(pyrrolidino)fullerene, Bis-PC, which forms only a single isomer due to geometrical restriction. When used in a tin perovskite solar cell with a PEA0.15FA0.85SnI3 (PEA: phenylethylammonium and FA: formamidinium) light absorption layer, the resulting open-circuit voltage (VOC) was 0.78 V, a value higher than that of fullerene monoadducts and comparable to that of the commonly used indene-C60 bisadduct (ICBA). The performance could be further improved by the composition engineering of perovskite, where the PEA0.15(FA0.87MA0.13)0.85SnI3 based device (MA: methylammonium) exhibited a photoelectric conversion efficiency of 12.3% with a VOC of 0.86 V. The device with single-isomer Bis-PC shows superior stability to that with mixed-isomer ICBA, retaining its initial performance after 3000 h storage under an inert atmosphere.
... Chen et al. (2012) reported a range from 1.39 to 1.46 eV and Patel et al. (2018) from 1.29 to 1.73 eV showing that the bandgap energy is strongly dependent on growth conditions, such as temperature, annealing atmosphere, doping, as well as other factors such as the presence of secondary phases and chemical composition. It should be noted that the optimal bandgap energy for the absorption layer in photovoltaic applications is generally between 1.1 and 1.6 eV (Rühle 2016). Too low a bandgap (below 1.1 eV) reduces the open-circuit voltage, thus lowering efficiency, while too high a bandgap (> 1.6 eV) increases voltage but limits the number of photons absorbed, which in turn lowers efficiency. ...
Article
Full-text available
In this study, we investigated the influence of tin concentration on the physical properties of eco-friendly CTS thin-film based solar cells deposited by means of the SILAR route. The results were discussed through several characterization techniques. XRD revealed the formation of Cu2SnS3 phase, along with peaks of CuS and Cu4S7 secondary phases, which diminished with increasing tin concentration. Raman spectroscopy confirmed the tetragonal crystalline structure of CTS films with (112) as the preferred orientation. The direct optical bandgap energy of the synthesized CTS films increased from 1.42 to 1.56 eV as the concentration of tin rose from 0.08 to 0.12 M. Electrical Hall effect measurements performed on the grown CTS layers revealed a p-type conductivity with hall mobility in the range 0.38–2.135 cm²/Vs and a carrier concentration between 3.93 × 10²¹ cm⁻³ and 7.68 × 10²¹ cm⁻³. Furthermore, using SCAPS-1D solar cell simulation software, the photovoltaic performance of the CTS-S1, CTS-S2 and CTS-S3 absorber layers has been evaluated. Despite the fact that the CTS-S1 absorber layer has more secondary phases and slightly lower mobility than the CTS-S2 and CTS-S3 layers, its excellent optical properties, including a high absorption coefficient (> 10⁴ cm⁻¹) and an optimal bandgap energy of 1.42 eV, enabled it to achieve the best efficiency of 8.46%.
... Also, CdTe is a direct-band gap material with possibility of band gap energy tuning from 1.4 to 1.5 eV, which is almost ideal for turning sunlight into electricity [41][42][43]. The ideal band gap of CdTe could surpass the Schockley-Queisser limit, allowing it to achieve efficiencies about 32% and a short circuit current density over 30 mA/cm 2 [44]. In addition to these advantages properties and efficient application, due to it's lower cost and high absorption coefficient [45,46], it is also used in some other novel applications, such as detectors [47] and photovoltaics [48]. ...
Article
Full-text available
Recently, optical thin-films with lower reflectivity have attracted much interest for their suitability in high performance thin-film solar cells and various modern photonics devices, such as electronic display panels touchscreens, smart optical glass windows, spectacles frames, super-compact camera lenses, laser systems and optical fiber communications since lowering reflectivity coating improves the device performances. However, obtaining reduced reflectance from this arrangement remains challenging issue. As the film optical properties, such as the absorbance, reflection and transmission of particular wavelength of electromagnetic radiation can be carefully controlled by optimizing thin-film fabrication materials as well as structures, there is a lot of research scope in optimizing device reflectivity by assessing various film- and substrate materials as well as their thicknesses. Therefore, in this study, the reflectance performances of optical thin-films were characterized for obtaining lower reflectivity for various types of modern photonics applications. To obtain this, three novel optoelectronic materials InGaAs, CdTe and CsPbBr3 for film layer, three widely used substrate materials glass, Al2O3 and steel as well as various thicknesses of film layer were evaluated. Reflectance studied of the thin-films for the three film materials have been clarified that CsPbBr3 is the best among these three film materials to be used for reducing the light reflection of the thin-film. Lower reflectivity of thin-films on glass substrate suggested that glass is better than both Al2O3 and steel as substrate in high efficiency thin-film solar cells and various photonics devices. In addition, evaluation of reflectance for various film thicknesses showed that ultra-thin film layer is superior for reducing the reflection of solar energy by thin-film structure. We have therefore proposed that thin-film with the combination of CsPbBr3 based ultra-thin film layer on glass substrate would be one of the best possible solutions for reducing reflectivity of solar cells and various photonics devices, thereby for possibly increasing the performance efficiency. This research result would be very beneficial for the development of renewable energy and photonics based nanotechnology, thereby play a significant role for reducing global energy crisis and green-house gas emission concurrently and sustainably in the modern world.
... [2] However, the power conversion efficiency (PCE) of Sb 2 Se 3 TF-SCs is still limited at a low level, let alone compared to the theoretical value. [3] The special asymmetric 1D band structure of Sb 2 Se 3 makes its conversion efficiency affected by the growth orientation, and complex bulk defects. [4] At the same time, its low carrier concentration (≈10 13 cm −3 ) [5] allows for a low built-in electric field strength when forming P-N heterojunctions with N-type materials. ...
Article
Full-text available
The quality of P‐N heterojunction is crucial for the performance of antimony selenide (Sb2Se3) solar cells and thus attracting urgent attention. In this work, the monovalent cation Ag⁺ is doped in CdS, which enhances the N‐type conductivity of CdS film anomalously and reduces its parasitic absorption simultaneously. Furthermore, Ag doping of CdS promotes the diffusion of Cd into the Sb2Se3 layer, forming CdSb defects, which enhances the P‐type conductivity of Sb2Se3 and reduces the density of deep‐level centers. With further chemical etching treatment on the CdS surface, the quality of the CdS/Sb2Se3 P‐N heterojunction is distinctly improved, making the energy band alignment of CdS/Sb2Se3 more favorable for carrier transportation. Finally, a remarkable efficiency of 8.14%, which is the highest efficiency among those with Jsc of 30.96 mA cm⁻², is achieved for vapor transport deposition processed Sb2Se3 solar cells. This work provides a strategy to simultaneously optimize the CdS and Sb2Se3 functional layers and enhance the quality of P‐N heterojunction for efficient Sb2Se3 solar cells.
Article
The influence of minimal amounts of Ag (0.5–1.4 at%) on elemental distribution and crystalline quality of (Ag,Cu)(In,Ga)Se 2 (ACIGSe) absorbers grown by the three‐stage coevaporation without added alkali elements is reported. The elemental ratios affect the amount of Ag to be uniformly incorporated into the chalcopyrite absorber and the open‐circuit voltage ( V OC ) of the ACIGSe solar cell devices. Ag‐containing absorbers deposited at 530 °C achieve a best photoconversion efficiency of 18.2%. Due to an increased V OC , ACIGSe absorbers perform better than their Ag‐free variants at low deposition temperatures. The factors contributing to this increased V OC of low‐temperature devices are: 1) enhanced elemental Ga and In interdiffusion and hence their spatial distribution across the absorber thickness, leading to an increase in the minimum bandgap, 2) an improved absorber crystalline quality with larger grains resulting in high quasi‐Fermi‐level splitting and lower nonradiative losses. The photoluminescence data obtained on the ACIGSe absorbers reveal the corresponding variations in their bandgap and photoluminescence quantum yield. These material‐level insights into Ag incorporation in chalcopyrite help to advance the development of chalcopyrite‐based tandem solar cells, which—so far—is limited by the requirement of high deposition temperatures.
Article
Full-text available
All-perovskite tandem solar cells (APTSCs) offer the potential to surpass the Shockley-Queisser limit of single-junction solar cells at low cost. However, high-performance APTSCs contain unstable methylammonium (MA) cation in the tin-lead (Sn-Pb) narrow bandgap subcells. Currently, MA-free Sn-Pb perovskite solar cells (PSCs) show lower performance compared with their MA-containing counterparts. This is due to the high trap density associated with Sn²⁺ oxidation, which is exacerbated by the rapid crystallization of MA-free Sn-containing perovskite. Here, a multifunctional additive rubidium acetate (RbAC) is proposed to passivate Sn-Pb perovskite. We find that RbAC can suppress Sn²⁺ oxidation, alleviate microstrain, and improve the crystallinity of the MA-free Sn-Pb perovskite. Consequently, the resultant Sn-Pb PSCs achieve a power conversion efficiency (PCE) of 23.02%, with an open circuit voltage (Voc) of 0.897 V, and a filling factor (FF) of 80.64%, and more importantly the stability of the device is significantly improved. When further integrated with a 1.79-electron volt MA-free wide-bandgap PSC, a 29.33% (certified 28.11%) efficient MA-free APTSCs with a high Voc of 2.22 volts is achieved.
Article
Sb 2 Se 3 was incorporated into precursor films. During annealing, Sb 2 Se 3 decomposes, releasing Sb and Se, which provides the necessary energy for grain growth through mass transport at boundaries, thereby promoting the performance of solar cells.
Article
Following the impressive efficiencies achieved for two‐terminal perovskite/silicon dual–junction solar cells, perovskite/perovskite/silicon triple‐junction cells have now gained attention and are rapidly developing. In a two‐terminal triple‐junction cell, maximizing the open‐circuit voltage ( V OC ) is not straightforward as it requires understanding and mitigating the dominant losses in such a complex structure. Herein, the high bandgap perovskite top cell is first identified as the main source of the V OC loss in the triple‐junction cell. A multifaceted optimization approach is then implemented that improves the V OC of the 1.83 eV perovskite. This approach consists of 1) replacing the reference triple‐cation/double‐halide with a triple‐cation/triple‐halide perovskite, which improves perovskite bulk quality and reduces transport losses, and 2) implementing a piperazinium iodide passivation between the perovskite and the electron transport layer, which reduces nonradiative recombination losses at this interface. Employing these optimizations in the top cell of the triple‐junction boost the V OC by average 124 mV. A high V OC of more than 3.00 V is achieved with a fill factor of 79.6%, a short‐circuit current density of 9.0 mA cm ⁻² , and an efficiency of 21.5%. Further study is conducted on the improvement of V OC in the triple‐junction solar cell using subcell selective photoluminescence‐based implied V OC imaging, which is applied for the first time to a perovskite‐based triple‐junction structure.
Article
The thermodynamical deprotonation of methylammonium chloride (MACl) has several detrimental influences on the quality of formamidinium (FA ⁺ )‐based perovskite, which limits both efficiency and stability of inverted perovskite solar cells (IPSCs). Herein, a new additive strategy was developed by introducing methyl carbamimidothioate hydroiodide (MCH) into perovskite precursor, where guanylation reaction occurred between MCH and MACl to form a new intermediate of methyl‐substituted guanidine (MSG). MSG could then bond with undercoordinated Pb ²⁺ to in situ form a two‐dimensional (2D) perovskite, which would promote the growth and crystallization of three‐dimensional (3D) perovskite with higher crystallinity, lower defect‐states density and superior stability. Finally, the MCH‐treated IPSC with a small area (0.09 cm ² ) achieved an impressive power conversation efficiency (PCE) of 26.81 % (certified as 26.02 %), which is one of the highest PCEs reported to date. The large area MCH‐treated device (1.00 cm ² ) also obtained a high PCE of 24.36 %. Moreover, the unencapsulated and MCH‐treated device exhibited excellent operational stability, maintaining 91.95 % and 97.06 % of their initial efficiencies after aging in air and a nitrogen‐filled atmosphere at 85 °C for 1200 h. The encapsulated MCH‐treated devices retained 94.25 % of its initial efficiency after continuously tracking at the maximum power‐point for 1200 h in air.
Article
Full-text available
Thermal co-evaporation of halide perovskites is a solution-free, conformal, scalable, and controllable deposition technique with great potential for commercial applications, particularly in multi-junction solar cells. Monolithic triple-junction perovskite solar cells have garnered significant attention because they can achieve very high efficiencies. Nevertheless, challenges arise in fabricating these devices, as they require multiple layers and precise current matching across complex absorber stacks. Here we demonstrate a current-matched monolithic all-perovskite p–i–n triple-junction solar cell enabled by controlled thermal co-evaporation of various absorber layers in the stack. The top and middle subcells were fabricated by developing optimized thermally co-evaporated Cs0.3FA0.7Pb(I0.56Br0.44)3 (1.80 eV bandgap) and FAPbI3 (1.53 eV) perovskites, respectively, while the bottom subcell employed a solution-processed Cs0.25FA0.75Pb0.5Sn0.5I3 (1.25 eV) perovskite. By optimising absorber thicknesses and compositions through optical modelling, we achieve excellent current matching between the top (9.6 mA cm⁻²), middle (9.3 mA cm⁻²), and bottom subcells (9.0 mA cm⁻²), achieving an overall efficiency of 15.8%. Optical modelling simulations suggest that current matching and efficiency up to 11.4 mA cm⁻² and 37.6% respectively could be attainable using the latest interlayer materials. This work highlights the potential of scalable vapour-based deposition techniques for advancing multi-junction perovskite-based solar cells, paving the way for future developments in this field.
Article
The lead-free inorganic perovskite metal oxide, BiFeO3 (BFO), presents promising potential for photovoltaic applications within solar cells. However, its limited light absorption and carrier mobility constrain the enhancement of its...
Article
Two-dimensional materials with a combination of a moderate bandgap, highly anisotropic carrier mobility, and a planar structure are highly desirable for nanoelectronic devices. This study predicts a planar BeP 2 monolayer...
Article
Full-text available
All-perovskite tandem solar cells (TSCs) hold the promise of surpassing the efficiency limits of single-junction solar cells. However, enhancing TSC efficiency faces the challenge of significant open-circuit voltage (VOC) loss...
Article
Luminescent solar concentrators (LSCs) have garnered considerable attention for their potential to enhance solar energy harvesting in photovoltaic (PV) systems. However, self-absorption often hinders their efficiency, caused by the overlap...
Article
Full-text available
Flexible emerging photovoltaic technologies, such as organic and perovskite photovoltaics, hold great potential for integration into tents, wearable electronics, and other portable applications. Recently, Fukuda et al. (2024) propose a bending test protocol for standardizing the mechanical performance characterization of flexible solar cells, focusing on 1% strain over 1 000 bending cycles. This marked an important step toward establishing consistency and good practices in the literature. However, even with this unified protocol, accurately comparing the mechanical flexibility of solar cells is hindered by the variated influence of parameters like thickness, bending radius, and power conversion efficiency (PCE) evolution during mechanical testing. Herein, a new figure of merit is introduced, the flexible photovoltaic fatigue factor (F), which integrates PCE retention, strain, and bending cycles into a cohesive framework. Guided by a detailed multilayer mechanical model, this metric enables more accurate strain analysis and promotes consistent reporting, paving the way for performance optimization in flexible photovoltaics.
Article
Surface iodine vacancies in a CsPbI 3 perovskite accelerate carrier recombination, while Lewis base groups, such as HCOO ⁻ , significantly enhance carrier lifetime and device efficiency.
Article
Full-text available
Triplet‐triplet annihilation photon upconversion (TTA‐UC) has emerged as a promising strategy for enhancing solar energy harvesting efficiency by converting two low‐energy, long‐wavelength photons into a high‐energy, short‐wavelength photon. In recent years, semiconductor nanocrystals have gained significant attention as efficient photosensitizers for TTA‐UC due to their excellent triplet energy transfer efficiency and the ability to tune their bandgap across the solar spectrum. This review focuses on the mechanism of NC‐based TTA‐UC, emphasizing key parameters to evaluate the performance of TTA‐UC systems. The influence of various material‐related factors on the overall NC‐based TTA‐UC performance is thoroughly discussed. Moreover, recent advances in solid‐state approaches for NC‐based TTA‐UC are highlighted, along with an overview of the current status of applications in this field. Lastly, this review identifies the challenges and opportunities that lie ahead in the future development of NC‐based TTA‐UC, providing insights into the potential advancements and directions for further research.
Article
The material choices for highly efficient multijunction solar cells (MJSCs) can be expanded by stacking lattice‐mismatched III–V materials grown by the inverted metamorphic approach. However, III–V materials are expensive, necessitating low‐cost strategies such as substrate reuse by epitaxial lift‐off (ELO) to improve their technology readiness. Inverted metamorphic MJSCs (IMM‐MJSCs) are inherently fragile due to the interfacial stresses introduced by graded buffer layers between mismatched materials. While numerous studies have reported successful fabrication of crack‐free IMM‐MJSCs, comprehensive procedural details and critical considerations are often left undisclosed. Herein, a systematic method is presented for achieving large‐area, crack‐free thin‐film IMM‐MJSCs. Specifically, the efficacy of the ELO bath method combined with Ag back electrode extension and the innovative application of rigid, acid‐ and polar solvent‐resistant plastics as temporary carriers during the process is demonstrated. By addressing the challenges of mechanical fragility and developing robust ELO techniques, this work aims to enable the practical implementation of high‐efficiency IMM‐MJSCs for space and terrestrial applications.
Article
Full-text available
Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since June 2012 are reviewed.
Article
Full-text available
Solar cells of which the efficiency is not limited by the Shockley-Queisser limit can be obtained by integrating a luminescent spectral conversion layer into the cell structure. We have calculated the maximum efficiency of state-of-the-art c-Si, pc-Si, a-Si, CdTe, GaAs, CIS, CIGS, CGS, GaSb, and Ge solar cells with and without an integrated spectral shifting, quantum cutting, or quantum tripling layer using their measured internal quantum efficiency (IQE) curves. Our detailed balance limit calculations not only take into account light in-coupling efficiency of the direct AM1.5 spectral irradiance but also wavelength dependence of the refractive index and the IQEs of the cells and the angular dependent light in-coupling of the indirect spectral irradiance. An ideal quantum cutting layer enhances all cell efficiencies ranging from a modest 2.9% for c-Si to much larger values of 4.0%, 7.7%, and 11.2% for CIGS, Ge, and GaSb, respectively. A quantum tripling layer also enhances cell efficiencies, but to a lesser extent. These efficiency enhancements are largest for small band gap cells like GaSb (7.5%) and Ge (3.8%). Combining a quantum tripling and a quantum cutting layer would enhance efficiency of these cells by a factor of two. Efficiency enhancement by a simple spectral shifting layer is limited to less than 1% in case the IQE is high for blue and UV lights. However, for CdTe and GaSb solar cells, efficiency enhancements are as high as 4.6% and 3.5%, respectively. A shifting layer based on available red LED phosphors like Sr2Si5N8:Eu will raise CdTe efficiency by 3.0%.
Article
Full-text available
We present a simple model of a molecular photovoltaic device consisting of a two-level system, connected to external contacts by chains of one or more charge transporting orbitals. Electrons may be promoted in the two-level system by photon absorption, and charge transported to the external circuit by electron transfer between neighboring orbitals. Photon absorption and emission are described by a generalized Planck equation and electron transfer is described by nonadiabatic Marcus theory. We find the steady-state current by solving the set of coupled rate equations for electron transfer in the system under illumination as a function of bias applied to the contacts. We calculate monochromatic current-voltage characteristics and power conversion efficiency as a function of the system size, orbital energy levels, and electron transfer rates, and compare with the monochromatic detailed balance limit. Using realistic values of the energy levels and charge-transfer rates, we are able to reproduce a number of commonly observed features in the current-voltage characteristics. These include a "kink" in the current-voltage curve close to open circuit when large interfacial energy steps are present or mobilities are low, and a reduction of the open-circuit voltage and crossing of the light and dark current curves when interfacial recombination is strong. We show that open-circuit voltage is dominated by the acceptor-donor energy gap when recombination is important, and by the optical gap when recombination is low. We confirm previous reports that photovoltaic energy conversion can be achieved by interfacial asymmetry alone and that a potential difference between the electrodes is unnecessary. Improved photovoltaic efficiency of molecular heterojunctions requires ohmic contacts, improved charge-carrier mobilities, and tuning of the electron-transfer rates at the heterojunction. Maximizing the rate of charge separation does not necessarily lead to maximum efficiency.
Article
Full-text available
The opportunities for photovoltaic (PV) solar energy conversion are reviewed in the context of projected world energy demands for the twenty-first century. Conventional single-crystal silicon solar cells are facing increasingly strong competition from thin-film solar cells based primarily on polycrystalline absorber materials, such as cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS). However, if PVs are to make a significant contribution to satisfy global energy requirements, issues of sustainability and cost will need to be addressed with increased urgency. There is a clear need to expand the range of materials and processes that is available for thin-film solar cell manufacture, placing particular emphasis on low-energy processing and sustainable non-toxic raw materials. The potential of new materials is exemplified by copper zinc tin sulphide, which is emerging as a viable alternative to the more toxic CdTe and the more expensive CIGS absorber materials.
Article
Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since July 2015 are reviewed.
Article
The following sections are included:* Introduction * Device design, materials and technology * Physics of QWs * Performance characteristics of QWSCs * Developments in QWSC design and performance * Limits to efficiency * Applications * Conclusions * References
Conference Paper
The standard Shockley-Queisser approach to ideal ultimate solar cell efficiency makes a number of idealistic assumptions. Under even slightly non-ideal conditions, the 4n2light trapping factor already has a major role controlling the ultimate efficiency.
Conference Paper
The standard Shockley-Queisser approach to ideal ultimate solar cell efficiency makes a number of idealistic assumptions. Under even slightly non-ideal conditions, the 4n2light trapping factor already has a major role controlling the ultimate efficiency.
Article
The remarkable advances over the past few years in performance of photovoltaic cells, including the advent of new absorber materials, call for an update to the previous assessment of prospects for future progress. The same simple criteria with some refinements, based on cell and module performance data, serve to evaluate and compare most types of solar cells. Apart from Si and InP, for all types the "best cells" have improved in conversion performances (and crystalline Si modules have made major strides in cost reduction). New cell types, such as "perovskite", sustainable chalcogenide, and quantum dot cells, are included. CdTe results bring those cells in line with other well-developed ones, lending some credence to the idea that the criteria provide the reader with knowledge, useful for gauging possible future technological developments. Additionally, the developments of the past few years show that, while the advent of more new cell types cannot be predicted, it can be aided and stimulated by innovative, daring, and creative new materials research.
Article
Poor ultraviolet (UV) quantum conversion efficiency contributes to a reduction in the efficiency of silicon based photovoltaic cells. In the UV, the main loss mechanism is through surface recombination of photo-generated carriers due to the shallow absorption depth of high energy photons. One method for greater utilisation of the UV region is by down-shifting UV photons to lower energies where the quantum efficiency of silicon is higher. This work determines the potential enhancement in efficiency that can be obtained by a luminescent down-shifting layer applied to silicon based solar cells. The efficiency is determined through detailed balance arguments. The maximum calculated efficiency enhancement due to an ideal down shifting process is 0.6% absolute using the AM1.5G standard spectra. Applying a similar analysis to a multicrystalline silicon solar cell results in an efficiency enhancement due to the down-shifting process of 0.17% absolute.
Article
The rapidly expanding field of polymer and organic solar cells is reviewed in the context of materials, processes and devices that significantly deviate from the standard approach which involves rigid glass substrates, indium-tin-oxideelectrodes, spincoated layers of conjugated polymer/fullerene mixtures and evaporated metal electrodes in a flat multilayer geometry. It is likely that significant advances can be found by pursuing many of these novel ideas further and the purpose of this review is to highlight these reports and hopefully spark new interest in materials and methods that may be performing less than the current state-of-the-art in their present form but that may have the potential to outperform these pending a larger investment in effort.
Article
The central problem that this paper addresses is the rapid and precise calculation of the energy and particle flux for detailed-balance photovoltaic applications. The calculation of energy and particle flux is essential to modeling the efficiencies and efficiency limits of solar energy conversion devices. Computing flux with the canonical Bose–Einstein integral is time consuming and, without due care, prone to error. The approach given herein, transforms the Bose–Einstein integral into a linear combination of incomplete Riemann zeta integrals. The numerical package that implements this method is benchmarked for precision by a number of means. These include comparisons between the Riemann zeta functions, and previously recorded values of solar cell limiting efficiencies from the literature. The rapidity of the numerical package is gauged by comparing the duration of flux calculations to other calculation methods.
Article
Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since June 2012 are reviewed.
Article
One of the major loss mechanisms leading to low energy conversion efficiencies of solar cells is the thermalization of charge carriers generated by the absorption of high-energy photons. These losses can largely be reduced in a solar cell if more than one electron–hole pair can be generated per incident photon. A method to realize multiple electron–hole pair generation per incident photon is proposed in this article. Incident photons with energies larger than twice the band gap of the solar cell are absorbed by a luminescence converter, which transforms them into two or more lower energy photons. The theoretical efficiency limit of this system for nonconcentrated sunlight is determined as a function of the solar cell’s band gap using detailed balance calculations. It is shown that a maximum conversion efficiency of 39.63% can be achieved for a 6000 K blackbody spectrum and for a luminescence converter with one intermediate level. This is a substantial improvement over the limiting efficiency of 30.9%, which a solar cell exposed directly to nonconcentrated radiation may have under the same assumption of radiative recombination only. © 2002 American Institute of Physics.
Article
A system for solar energy conversion using the up-conversion of sub-band-gap photons to increase the maximum efficiency of a single-junction conventional, bifacial solar cell is discussed. An up-converter is located behind a solar cell and absorbs transmitted sub-band-gap photons via sequential ground state absorption/excited state absorption processes in a three-level system. This generates an excited state in the up-converter from which photons are emitted which are subsequently absorbed in the solar cell and generate electron-hole pairs. The solar energy conversion efficiency of this system in the radiative limit is calculated for different cell geometries and different illumination conditions using a detailed balance model. It is shown that in contrast to an impurity photovoltaic solar cell the conditions of photon selectivity and of complete absorption of high-energy photons can be met simultaneously in this system by restricting the widths of the bands in the up-converter. The upper limit of the energy conversion efficiency of the system is found to be 63.2% for concentrated sunlight and 47.6% for nonconcentrated sunlight. © 2002 American Institute of Physics.
Article
Recently, a new field in photovoltaics (PV) has emerged, focusing on solar cells that are entirely based on metal oxide semiconductors. The all-oxide PV approach is very attractive due to the chemical stability, nontoxicity, and abundance of many metal oxides that potentially allow manufacturing under ambient conditions. Already today, metal oxides (MOs) are widely used as components in PV cells such as transparent conducting front electrodes or electron-transport layers, while only very few MOs have been used as light absorbers. In this Perspective, we review recent developments of all-oxide PV systems, which until today were mostly based on Cu2O as an absorber. Furthermore, ferroelectric BiFeO3-based PV systems are discussed, which have recently attracted considerable attention. The performance of all-oxide PV cells is discussed in terms of general PV principles, and directions for progress are proposed, pointing toward the development of novel metal oxide semiconductors using combinatorial methods.
Article
A generalized solar cell model for excitonic and classical bipolar solar cells describes the combined transport and interaction of electrons, holes, and excitons in accordance with the principle of detailed balance. Conventional inorganic solar cells, single-phase organic solar cells and bulk heterojunction solar cells, i.e., nanoscale mixtures of two organic materials, are special cases of this model. For high mobilities, the compatibility with the principle of detailed balance ensures that our model reproduces the Shockley-Queisser limit irrespective of how the energy transport is achieved. For less ideal devices distinct differences become visible between devices that are described by linear differential equations and those with nonlinear effects, such as a voltage-dependent collection in bipolar p-i-n-type devices. These differences in current-voltage characteristics are also decisive for the validity of the reciprocity theorem between photovoltaic quantum efficiency and electroluminescent emission. Finally, we discuss the effect of band offset at the heterointerface in a bulk heterojunction cell and the effect of the average distances between these heterointerfaces on the performance of a solar cell in order to show how our detailed balance model includes also these empirically important quantities.
Article
We calculate the radiative efficiency limits of organic bulk heterojunction solar cells according to the theory of Shockley and Queisser and compare the results with experimental device performance. The difference between limiting theory (23% power conversion efficiency) and experimental data (4%) is explained and quantified by five reasons, namely the energy level misalignment at the donor/acceptor heterointerface of the bulk heterojunction, insufficient light trapping, low exciton diffusion lengths, nonradiative recombination, and low charge carrier mobilities. Comparison of the impact of the different loss mechanisms by numerical simulation reveals that efficiencies above 10% using PF10TBT/PCBM blends will require mostly a strong reduction of nonradiative recombination. The energy misalignment and the low carrier mobilities appear as a second-order restriction in this type of blend.
Article
The fundamental (detailed balance) limit of the performance of a tandem structure is presented. The model takes into account the fact that a particular cell is not only illuminated by part of the solar irradiance but also by the electroluminescence of other cells of the set. Whereas, under 1 sun irradiance, a single solar cell only converts 30% of the solar energy, a tandem structure of two cells can convert 42%, a tandem structure of three cells can convert 49%, etc. Under the highest possible light concentration, these efficiencies are 40% (one cell), 55% (two cells), 63% (three cells), etc. The model also allows us to predict the ideal efficiency of a stack with an infinite number of solar cells. Such a tandem system can convert 68% of the unconcentrated sunlight, and 86% of the concentrated sunlight.
Article
In a thermodynamic treatment electromagnetic radiation of any kind is described. The difference between thermal and non-thermal radiation is accounted for by introducing the chemical potential of photons. Instead of an effective temperature all kinds of radiation have the real temperature of the emitting material. As a result Planck's law for thermal radiation is extended to radiation of any kind. The concept of the chemical potential of radiation is discussed in detail in conjunction with light-emitting diodes, two-level systems, and lasers. It allows the calculation of absorption coefficients, of emission spectra of luminescent materials, and of radiative recombination lifetimes of electrons and holes in semiconductors. Theoretical emission spectra are compared with experimental data on GaAs light-emitting diodes and excellent agreement is obtained.
Article
Theoretical efficiencies are derived in a detailed balance calculation for thermophotovoltaic solar energy conversion, where solar radiation is absorbed by an intermediate absorber, which emits radiation inside an evacuated housing towards a solar cell. For ideal components with no optical losses and only radiative recombination in the solar cell, maximal efficiencies are found of 85% for full concentration of the incident sunlight on a black absorber, and of 54% for no concentration and a selective absorber absorbing only for ω > 0.92 eV. This is considerably larger than the efficiency for directly illuminated solar cells with also only radiative recombination, the Shockley–Queisser limit, which is 41% for full concentration and 30% for no concentration. In order to approach efficiency limits for real TPV systems, several non-idealities have been introduced: (a) realistic assumptions about the geometry of the intermediate absorber, (b) optical losses of 5% for photons with energy below the band gap of the solar cell and (c) non-radiative recombination in the solar cell of the same amount as radiative recombination. This reduces the efficiency for non-concentrated sunlight to only 32.8%, but for very high concentrations of 10000 and above suitable absorber geometries still seem to allow efficiencies close to 60%.
Article
Ein Körper, der in einer Hülle sich befindet, deren Temperatur der seinigen gleich ist, ändert durch Wärmestrahlung nicht seine Temperatur, absorbiert also in einer gewissen Zeit eben so viel Strahlen als er aussendet. Schon vor langer Zeit hat man hieraus den Schluß gezogen, daß bei derselben Temperatur das Verhältnis zwischen dem Emissionsvermögen und dem Absorptionsvermögen für alle Körper das gleiche ist. Dabei hat man vorausgesetzt, daß die Körper nur Strahlen einer Gattung aussenden. Dieser Satz ist durch Versuche, namentlich von den Hrn. de la Provostaye und Desains in vielen Fällen bestätigt gefunden, in denen die Gleichartigkeit der ausgesendeten Strahlen wenigstens näherungsweise insofern vorausgesetzt werden konnte, als die Strahlen dunkle waren. Ob ein ähnlicher Satz gilt, wenn die Körper gleichzeitig Strahlen verschiedener Gattung aussenden, was strenggenommen wohl immer der Fall ist, darüber ist bisher weder durch theoretische Betrachtungen noch durch Versuche etwas ermittelt. Ich habe nun gefunden, daß jener Satz seine Gültigkeit auch dann behält, sobald man nur unter dem Emissionsvermögen die Intensität der ausgesendeten Strahlen einer Gattung versteht und das Absorptionsvermögen auf Strahlen derselben Gattung bezieht.
Article
The limiting efficiency of photovoltaic devices follows from the detailed balance of absorption and emission of a diode according to the Shockley–Queisser theory. However, the principle of detailed balance has more implications for the understanding of photovoltaic devices than only defining the efficiency limit. We show how reciprocity relations between carrier collection and dark carrier injection, between electroluminescence emission and photovoltaic quantum efficiency and between open circuit voltage and light emitting diode quantum efficiency all follow from the principle of detailed balance. We also discuss the validity range of the Shockley–Queisser limit and the reciprocity relations. Discussing the validity of the reciprocity relations helps to deepen the understanding of photovoltaic devices and allows us to identify interrelationships between the superposition principle, the diode ideality and the reciprocity relations. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Article
Tandem stacks of solar cells have clearly shown their ability to increase the efficiency of solar energy conversion. This paper investigates the limiting efficiency of unconstrained and the series constrained two-terminal tandem solar stacks under blackbody and AM radiation for stacks containing up to six cells. The efficiency limit under maximally concentrated blackbody radiation for the unconstrained device which contains a large number of cells has previously been calculated to be 86.8%. Surprisingly, the same limit has been shown to apply even when the cells are constrained in series connected two-terminal configuration. This represents the upper limit for conversion of the Sun's energy to electricity.Low-dimensional structures may offer advantages for two-terminal tandem stacks in the future, for example, by using superlattices of different periodicity to engineer the band gap while maintaining constant lattice spacing. In such a way, a generic approach to the design of tandem cells may be developed that would make it much simpler to increase the number of cells in a tandem stack then at present.
Article
Highest confirmed “one-sun” cell and module results are reported in Tables I and II. Any changes in the tables from those previously published 3 are set in bold type. In most cases, a literature reference is provided that describes either the result reported or a similar result. Table I summarises the best measurements for cells and submodules, while Table II shows the best results for modules. Table III contains what might be described as ‘notable exceptions’. While not conforming to the requirements to be recognized as a class record, the cells and modules in this Table have notable characteristics that will be of interest to sections of the photovoltaic community with entries based on their significance and timeliness.
Article
In order to find an upper theoretical limit for the efficiency of p‐n junction solar energy converters, a limiting efficiency, called the detailed balance limit of efficiency, has been calculated for an ideal case in which the only recombination mechanism of hole‐electron pairs is radiative as required by the principle of detailed balance. The efficiency is also calculated for the case in which radiative recombination is only a fixed fraction f c of the total recombination, the rest being nonradiative. Efficiencies at the matched loads have been calculated with band gap and f c as parameters, the sun and cell being assumed to be blackbodies with temperatures of 6000°K and 300°K, respectively. The maximum efficiency is found to be 30% for an energy gap of 1.1 ev and f c = 1. Actual junctions do not obey the predicted current‐voltage relationship, and reasons for the difference and its relevance to efficiency are discussed.
Article
The principle of detailed balance was used in 1960 to derive a thermodynamic limit for energy conversion efficiency of semiconductor junction photovoltaic cells. Absorption and emission of photons must be balanced, the cell being a black body. Non-radiative recombinations of solar-generated electron–hole pairs are thus particularly deleterious, affecting silicon junctions. Gallium arsenide, however, is inherently more efficient because of its direct band gap with predominant radiative transitions. The maximal efficiency shows a broad maximum as a function of the semiconductor energy gap. Silicon lies within this maximum. Detailed balance and its applications are reviewed. Current efforts to overcome this limit are discussed. Concentrated illumination enhances efficiencies; multijunction cells – not covered in the detailed balance limit – deliver higher output. Attempts are made to more fully utilize the blue solar spectrum.
Article
This paper reviews the experimental and theoretical studies of quantum well solar cells with an aim of providing the background to the more detailed papers on this subject in these proceedings. It discusses the way quantum wells enhance efficiency in real, lattice matched material systems and fundamental studies of radiative recombination relevant to the question of whether such enhancements are possible in ideal cells. A number of theoretical models for quantum well solar cells (QWSCs) are briefly reviewed and more detail is given of our own group's model of the dark-currents. The temperature and field dependence of QWSCs are all briefly reviewed.
Article
Multigap systems are better matched to the sun's spectrum than single gap systems and are, therefore, more efficient as photovoltaic converters. This paper reviews the different thermodynamic approaches used in the past for computing the limiting efficiency for the conversion of solar energy into work. Within this thermodynamic context, the limit ranges from 85.4% to 95.0% depending on the assumptions made. Detailed balance theory provides a more accurate model of the photovoltaic converter. It leads to a limit of 86.8% for a system with an infinite number of cells, as already pointed out by other authors. In this work, however, we use the concepts of angle and energy restriction to emphasize that this limit is independent of the light concentration. Systems with a finite number of cells are also studied and their limiting efficiency is found to be higher than previously reported. Data for AM1.5 Direct spectrum, never computed before, are included.
Article
What are the solar cell effi ciencies that we can strive towards? We show here that several simple criteria, based on cell and module performance data, serve to evaluate and compare all types of today's solar cells. Analyzing these data allows to gauge in how far signifi cant progress can be expected for the various cell types and, most importantly from both the science and technology points of view, if basic bounds, beyond those known today, may exist, that can limit such progress. This is important, because half a century after Shockley and Queisser (SQ) presented limits, based on detailed balance calculations for single absorber solar cells, those are still held to be the only ones, we need to consider; most efforts to go beyond SQ are directed towards attempts to circumvent them, primarily via smart optics, or optoelectronics. After formulating the criteria and analyzing known loss mechanisms, use of such criteria suggests-additional limits for newer types of cells, Organic and Dye-Sensitized ones, and their siblings,-prospects for progress and-further characterization needs, all of which should help focusing research and predictions for the future.
Article
Several classes of semiconductor quantum dots (QD), including groups II-VI, III-V, IV-VI, IV, and their alloys as well as various intergroup and intragroup core-shell configurations, and nanocrystal shapes have been synthesized. One approach to enhance efficiency in QD-based PV cells compared to conventional bulk semiconductor-based PV is to create efficient multiple exciton generation from a large fraction of the photons in the solar spectrum. Three generic types of QD solar cells that could utilize MEG to enhance conversion efficiency can be defined. They include photoelectrodes composed of QD arrays that form either Schottky junctions with a metal layer, a hetero p-n junction with a second NC semiconductor layer, or the i-region of a p-i-n device, QD-sensitized nanocrystalline TiO2 films, and QDs dispersed into a multiphase mixture of electron- and hole-conducting matrices, such as C60 and hole conducting polymers.
Article
Quantum-dot-sensitized solar cells (QDSCs) are a promising low-cost alternative to existing photovoltaic technologies such as crystalline silicon and thin inorganic films. The absorption spectrum of quantum dots (QDs) can be tailored by controlling their size, and QDs can be produced by low-cost methods. Nanostructures such as mesoporous films, nanorods, nanowires, nanotubes and nanosheets with high microscopic surface area, redox electrolytes and solid-state hole conductors are borrowed from standard dye-sensitized solar cells (DSCs) to fabricate electron conductor/QD monolayer/hole conductor junctions with high optical absorbance. Herein we focus on recent developments in the field of mono- and polydisperse QDSCs. Stability issues are adressed, coating methods are presented, performance is reviewed and special emphasis is given to the importance of energy-level alignment to increase the light to electric power conversion efficiency.
Article
The intermediate band (IB) solar cell has been proposed to increase the current of solar cells while at the same time preserving the output voltage in order to produce an efficiency that ideally is above the limit established by Shockley and Queisser in 1961. The concept is described and the present realizations and acquired understanding are explained. Quantum dots are used to make the cells but the efficiencies that have been achieved so far are not yet satisfactory. Possible ways to overcome the issues involved are depicted. Alternatively, and against early predictions, IB alloys have been prepared and cells that undoubtedly display the IB behavior have been fabricated, although their efficiency is still low. Full development of this concept is not trivial but it is expected that once the development of IB solar cells is fully mastered, IB solar cells should be able to operate in tandem in concentrators with very high efficiencies or as thin cells at low cost with efficiencies above the present ones.
Article
Two organolead halide perovskite nanocrystals, CH(3)NH(3)PbBr(3) and CH(3)NH(3)PbI(3), were found to efficiently sensitize TiO(2) for visible-light conversion in photoelectrochemical cells. When self-assembled on mesoporous TiO(2) films, the nanocrystalline perovskites exhibit strong band-gap absorptions as semiconductors. The CH(3)NH(3)PbI(3)-based photocell with spectral sensitivity of up to 800 nm yielded a solar energy conversion efficiency of 3.8%. The CH(3)NH(3)PbBr(3)-based cell showed a high photovoltage of 0.96 V with an external quantum conversion efficiency of 65%.
Article
A semiconductor in the solar radiation field acts as a thermal electronic engine. It converts absorbed radiation heat into chemical energy of the excited electron-hole gas. In flow equilibrium, a homogeneous semiconductor gives off this chemical energy by radiative recombination to the surroundings. If provision is made, as by a p-n junction, to divert the excited electrons and holes, before they recombine, from their point of generation, their chemical energy may be converted into electrical energy. The ratio of this chemical energy current, which constitutes an upper limit for the obtainable electrical energy current, to the absorbed heat current is computed as a function of the value of the bandgap of the semiconductor. Under the assumption that the absorptivity of the electron-hole system of the semiconductor is unity for photon energies larger than the bandgap and zero for smaller photon energies, the conversion efficiency for unfocussed sunlight has a maximum of 30 percent for a bandgap of 1:3 eV.
Guidelines for PV power measurement in industry
  • N Taylor
  • E Dunlop
  • F Fabero
  • G Friesen
  • W Herrmann
  • J Hohl-Ebinger
Taylor, N., Dunlop, E., Fabero, F., Friesen, G., Herrmann, W., Hohl-Ebinger, J., et al., 2010. Guidelines for PV power measurement in industry. Ispra. http://dx.doi.org/10.2788/90247.
The chemical potential of radiation
  • P Wü Rfel
Wü rfel, P., 1982. The chemical potential of radiation. J. Phys. C Solid State Phys. 15, 3967–3985. http://dx.doi.org/10.1088/0022-3719/15/18/ 012.
Quantum well solar cells
  • K W J Barnham
  • I Ballard
  • J P Connolly
  • N J Ekins-Duakes
  • B G Kluftinger
  • J Nelson
Barnham, K.W.J., Ballard, I., Connolly, J.P., Ekins-Duakes, N.J., Kluftinger, B.G., Nelson, J., et al., 2002. Quantum well solar cells. Phys. E 14, 27-36. http://dx.doi.org/10.1016/S0169-4332(96)00876-8.