Andreas Hinsch

Fraunhofer Institute for Solar Energy Systems | ISE · Organic and Perovskite Photovoltaics

While perovskite photovoltaic (PV) devices are on the verge of commercialization, promising methods to recycle or remanufacture fully encapsulated perovskite solar cells (PSCs) and modules are still missing. Through a detailed life-cycle assessment shown in this work, we identify that the majority of the greenhouse gas emissions can be reduced by r...

The stabilization of grain boundaries and surfaces of the perovskite layer is critical to extend the durability of perovskite solar cells. Here we introduced a sulfonium-based molecule, dimethylphenethylsulfonium iodide (DMPESI), for the post-deposition treatment of formamidinium lead iodide perovskite films. The treated films show improved stabili...

Perovskite photovoltaics have emerged as a cost-effective, fast developing technology with interesting light harvesting properties allowing for impressive breakthroughs in the field photovoltaic solar energy conversion. Charge selective layers are crucial to achieving optimal performances in this kind of solar cells. This conference paper presents...

A sacrificial film of polystyrene nanoparticles was utilized to introduce nano-cavities in mesoporous metal oxide layers. This enabled the growth of larger perovskite crystals inside the oxide scaffold with significantly...

A sacrificial film of polystyrene nanoparticles was utilized to introduce nano-cavities in mesoporous metal oxide layers. This enabled the growth of larger perovskite crystals inside the oxide scaffold with significantly suppressed non-radiative recombination and improving device performance. This work exemplifies potential applications of such nan...

Halide perovskite solar cells (PSCs) have achieved power conversion efficiencies (PCEs) approaching 26%, however, the stability issue hinders their commercialization. Due to the soft ionic nature of perovskite materials, the strain effect on perovskite films has been recently recognized as one of the key factors that affects their opto-electronic p...

While perovskite photovoltaic (PV) devices are on the verge of their commercialization, promising methods to recycle or remanufacture fully-encapsulated perovskite solar cells (PSCs) and modules are still missing. Through detailed life-cycle assessment shown in this work, we identify that the majority of the greenhouse gas emissions can be reduced...

The photocurrent density-voltage (J(V)) curve is the fundamental characteristic to assess opto-electronic devices, in particular solar cells. However, it only yields information on the performance integrated over the entire active device area. Here, a method to determine spatially resolved photocurrent images by voltage-dependent photoluminescence...

Interface engineering and passivating contacts are key enablers to reach the highest efficiencies in photovoltaic devices. While printed carbon–graphite back electrodes for hole‐transporting material (HTM)‐free perovskite solar cells (PSCs) are appealing for fast commercialization of PSCs due to low processing costs and extraordinary stability, thi...

Carbon‐based electrodes represent a promising approach to improve stability and up‐scalability of perovskite photovoltaics. The temperature at which these contacts are processed defines the absorber grain size of the perovskite solar cell: in cells with low‐temperature carbon‐based electrodes (L‐CPSCs), layer‐by‐layer deposition is possible, allowi...

Carbon-electrode based perovskite solar cells (C-PSCs) are promising candidates for commercialization thanks to their high stability. However, the absence of a hole selective layer (HSL) often limits their performance yielding to low fill factors (FF). This study focuses on a certified FF of 78.8% obtained through HSL-free C-PSCs. This is found to...

Improving stability has become one of the most important objectives in the practical application of perovskite photovoltaics. Here, we develop encapsulated mesoporous-carbon perovskite solar mini-modules that retain more than 92% of their initial performance after 3,000 h of damp-heat aging at 85°C/85% relative humidity, while maintaining 90% of th...

The photocurrent density-voltage (J(V)) curve is the fundamental characteristic to assess opto-electronic devices, in particular solar cells. However, it only yields information on the performance integrated over the entire active device area. Here, a method to determine a spatially resolved photocurrent image by voltage-dependent photoluminescence...

Tremendous efforts have been dedicated toward minimizing the open-circuit voltage deficits on perovskite solar cells (PSCs), and the fill factors are still relatively low. This hinders their further application in large scalable modules. Herein, we employ a newly designed ammonium salt, cyclohexylethylammonium iodide (CEAI), for interfacial enginee...

One of the key challenges of perovskite photovoltaics (PV) is the long-term stability. Although efforts have been made to improve the lifetime of perovskite PV devices, their degradation under reverse-bias conditions has been barely addressed. In this work, perovskite solar cells with carbon-based electrodes are presented which demonstrate superior...

A certified world record efficiency of 15,5% for hole selective layer free carbon electrode perovskite solar cells is reported. A world record fill factor of 78,8% is also achieved through the certified measurements. The Fill Factor limitations in hole selective free perovskite solar cells are examined: The ideality factor and VOC are found to inf...

In this work we compare seven different types of natural and synthetic graphite particles and examine how their integration into the cathode of carbon-based perovskite solar cells (C-PSCs) is influencing their opto-electronic properties. By combining x-ray diffraction, Raman spectroscopy and 4-point probe measurements we show that the differences i...

We demonstrate the effect of sheet conductivity and infiltration using the example of two graphite types, showing that, in general, the graphite type is very important. Amorphous and pyrolytic graphite were applied to carbon electrodes in fully printable carbon-based multiporous-layered-electrode perovskite solar cells (MPLE-PSCs): <glass/F-doped S...

Perovskite solar cells (PSCs) have achieved a photoelectric conversion efficiency of 25 % and can be manufactured only by printing and coating processes, so it expected to be commercialized. However, the organic materials used for PSCs are very unstable to water and oxygen, so long-term durability needs to be improved. Therefore, we focused on a PS...

A physical model to explain the 2D charge recombination in mesoscopic graphite‐based perovskite solar cells (PSCs) having a highly selective front electrode and a nonselective back electrode is presented. Steady‐state photovoltage and photoluminescence (PL) as well as transient PL are studied for a wide range of device configurations, providing ins...

Carbon-based electrodes have been widely applied in perovskite solar cells (PSCs) because of their chemical inertness and compatibility with up-scalable techniques, signifying their solid potential for mass-production. The material scarcity and complexity of metal ore extraction further highlights that conventionally used noble metal electrodes can...

Variations in the time courses of the activation of fully-printable carbon-based multi-porous-layered-electrode perovskite solar cells (MPLE-PSCs) can lead to differences between the photocurrent density (Jsc) values obtained from one-sun photocurrent density-voltage (J–V) measurements and from incident-photon-to-current efficiency (IPCE) integrati...

SnO2 is nowadays the widely preferred material as an electron transport layer (ETL) in most n‐i‐p planar perovskite solar cells (PSCs) owing to their facility for ambient, low temperature processing and UV stability. Most of the reports published so far study device stability on full cells. This report investigates the role of slot‐die coated SnO2...

The liquefaction and recrystallization of CH3NH3PbI3 perovskite with methylamine - MA⁰/CH3NH2 gas in solar cells have been intensively studied in the past years, yet the exact mechanisms remained hypothesized and unclear due to lack of experimental evidence. The investigation presented in this work connects the interatomic bonding in the methylamin...

Although it still contributes to less than 2% of the worldwide electricity generation, photovoltaics (PVs) is on the way to becoming a key energy technology for a global future renewable energy infrastructure. We present projections of worldwide CO2 emissions of the future PV industry, finding that these emissions will likely surpass those caused b...

The electrically insulating space layer takes a fundamental role in monolithic carbon-graphite based perovskite solar cells (PSCs) and it has been established to prevent the charge recombination of electrons at the mp TiO2/carbon-graphite (CG) interface. Thick 1 µm printed layers are commonly used for this purpose in the established triple-mesoscop...

A projection of worldwide CO2 emissions of the future PV industry is initially presented. We investigate the development of gross global CO2-emissions from the PV industry towards a sustainable energy future. This is the basis for our motivation to propose a fully printed integrated carbon-based PV module concept as alternative pathway to strongly...

Molding of a dense film of spherical poly(acrylate/methyl methacrylate) (PAA‐PMMA) beads is used as unique templating agent to obtain TiO2 scaffold layers with controlled porosity. The porosity obtained is of hundreds of nanometers, much larger than the one typically reported for the porous layers of Grätzel‐ or perovskite‐ type cells. It is shown...

The determination of certified efficiency values for perovskite solar cells from current-voltage sweeps is under growing discussion. Here, we report for the first time a certified steady-state solar efficiency for a hole transport layer (HTL) free perovskite cell of 12.6 % measured continuously at maximum power point in an accredited laboratory. By...

Relating crystallization of the absorber layer in a perovskite solar cell (PSC) to the device performance is a key challenge for the process development and in-depth understanding of these types of high efficient solar cells. A novel approach that enables real-time photo-physical and electrical characterization using a graphite-based PSC is introdu...

Silicon-based tandem solar cells can overcome the efficiency limit of single junction silicon solar cells. Perovskite solar cells are particularly promising as a top cell in monolithic tandem devices due to their rapid development towards high efficiencies, a tunable band gap with a sharp optical absorption edge and a simple production process. In...

The most efficient organic-inorganic perovskite solar cells (PSCs) contain the conventional n-i-p mesoscopic device architecture using a semiconducting TiO2 scaffold combined with a compact TiO2 blocking layer for selective electron transport. These devices achieve high power conversion efficiencies (15% to 22%), but mainly require high-temperature...

Lead halide perovskite solar cells have shown a tremendous rise in power conversion efficiency with reported record efficiencies of over 20% making this material very promising as a low cost alternative to conventional inorganic solar cells. However, due to a differently severe “hysteretic” behaviour during current density-voltage measurements, whi...

Platinum (Pt)-free counter electrodes (CEs) are economical alternative components of dye-sensitized solar cells (DSSCs) that have attracted much interest and become the focus of research, with an increasingly large number of scientific papers published in the last two decades. The development of these CE materials was driven mainly by desires to ov...

In this study, silica samples with different structure and particle size were used as additives for the stabilization of liquid electrolytes in Dye Sensitized Solar Cells (DSSCs) in order to assess the influence on the final performances of the devices. In particular, three different silica-based materials were synthetized: monodispersed silica par...

CH3NH3PbI3 perovskite solar cells with a mesoporous TiO2 layer and spiro-MeOTAD as a hole transport layer (HTL) with three different CH3NH3I concentrations (0.032 M, 0.044 M and 0.063 M) were investigated. Strong variations in crystal size and morphology resulting in diversified cell efficiencies (9.2%, 16.9% and 12.3%, respectively) were observed....

An in-situ analysis of I3- formation in an iodine-free electrolyte is carried out using electro-diffuse-reflection spectroscopy (EDRS). Using EDRS, a monochromatic blue laser source irradiates the photo-anode at an incident angle of 45°. The intensity of scattered light is varied by modulating the cell potential. This novel EDRS method enables the...

Novel nickel(II)benzo-diimino-semiquinonate and palladium(II)benzo-imino-semiquinonate complexes were synthesized, tested regarding their applicability in dye sensitized solar cells, and characterized optically and electrochemically. All the dyes showed a strong absorption in the near infrared region. Various electron-withdrawing substituents were...

The synthesis and properties of four new ruthenium dyes for TiO2-based dye-sensitized solar cells are presented. Bipyridine ligands with triarylamine or indoline moieties as donors, which differ both in the size of their conjugated π systems and in their hydrophobicity, have been introduced into thiocyanate (SCN)-free and SCN-containing complexes....

Recently, the first commercial dye solar cell (DSC) products based on the mesoscopic principle were successfully launched. Introduction to the market has been accompanied by a strong increase in patent applications in the field during the last four years, which is a good indication of further commercialization activity. Materials and cell concepts...

Electrochemical properties of structurally modified quasi-solid-state electrolytes were examined using porous substrates (PSs). The PS was prepared into two categories by a phase inversion method with a brominated poly(phenylene oxide) (BPPO): the sponge and finger types. Effects of the humidification and cosolvent compositions on the morphology of...

A simple manufacturing process based on screen-printing is crucial for a successful commercialization of dye-sensitized solar cells (DSSCs). We developed the sol–gel based TiO2 paste in such a way that solely a single step deposition is sufficient to realize a sponge-like structure of the layer assuring its high activity in DSSCs. For the first tim...

The present work investigates the UV stability of the dye-sensitized solar cell (DSC) by parametrical investigation of the material influence on UV stability. UV illumination has been observed to cause degradation by slow photocatalysis in the DSC. Photooxidized impurities represent an unwanted side reaction with the redox pair of the electrolyte a...

Dye solar cells have been investigated by charge carrier extraction under short and open circuit conditions and an illumination intensity equivalent to 1 sun (AM 1.5). Under short circuit conditions, a surprisingly high amount of charge carriers stored in the nanoporous TiO2 network has been observed. A theoretical model was developed to describe t...

To ensure long-term stable dye-sensitized solar cells (DSCs) and modules, a hermetic sealing is required.This research investigates the chemical stability of I−/I3 − redox electrolyte and four different glass frits (GFs). Sintered GF layers were openly exposed to nonaqueous redox electrolyte and redox electrolyte with 1, 5, and 10wt% H2O in thin, e...

Large-scale (6000 cm2) dye solar cell modules were developed using a meander and integrated series connection design in combination with a glass frit-sealing technique. The manufacturing process, as developed at Fraunhofer Institute for Solar Energy Systems (ISE) for glass frit-sealed dye solar cell modules, is based entirely on screen printing and...

Nanotechnology can be applied to the whole value chain of the energy sector: energy sources - energy conversion - energy distribution - energy storage and energy use. The overview of the possible application range of nanotechnology in the energy sector (see Figure 1.7) shows the vast and broad variety of possible products and applications. In this...

To ensure long-term stable dye-sensitized solar cells (DSCs) and modules a hermetic sealing is required. This research investigates the chemical stability of I-/I3- redox electrolyte and four different glass frits (GF). Sintered GF layers were openly exposed to non-aqueous redox electrolyte and redox electrolyte with 1, 5 and 10 wt% H2O in thin, en...

We have investigated carrier transport and trapping in blends of 6:5 wt. P3HT:PCBM that are important for the development of organic Solar cells. The devices with the inverted layer sequence and solar efficiency of 3.7% were analysed. We demonstrate that, though the fill factor of the IV characteristics is as high as 68%, carrier trapping is effect...

Charge carrier transport and trapping was investigated in organic solar cell structures consisting of poly-3-hexylthiophene blended with the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester in 6:5 weight ratio. The analysed devices having solar efficiency of 3.7 per cent were produced in the inverted layer sequence. The fill factor o...

Within the German research projects ColorSol and InnoCo, a focus is put on the scaling-up of glass based dye solar cell modules and the development of a production technology. This paper reports on the successful scaling-up from 30* 30 cm to 60* 100 cm prototypes. First characteristics of these modules are lined out. The developed modules aim for a...

With respect to a first market introduction, one advantage of dye solar cell (DSC) modules is the combination of photovoltaic (PV) solar electricity with decorative aspects. We report on the recent results achieved in the frame of the German project ColorSol. The project focuses on the application field of building-integrated PVs (facades, PV-glazi...

This work describes the properties of a series of dye solar cells that were sensitized with hyperbranched polymers carrying two different chromophoric units. One of the units was a carboxylated ruthenium complex, acting as sensitizer and energy acceptor, while the other was a fluorescent dye, acting as additional light absorber and energy donor. Wi...

Three types of screen-printable catalytic pastes were successfully prepared to be used as counterelectrode for monolithic dye solar cells encapsulated with glass frit. The electroless bottom-up method or so-called polyol process has been applied to fabricate thermally stable SnO2:Sb/Pt and carbon black/Pt nanocomposites. The catalytic and electric...

We report the investigation of carrier transport as affected by trapping states in blends of poly-3-hexylthiophene (P3HT) with the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) that are promising materials for the organic solar cell development. Devices have been fabricated from P3HT:PCBM blends with 6:5 wt. ratio in the in...

In this paper, we report on the outcome of a German network project conducted with 12 partners from universities and research institutes on the material development of dye solar cells (DSC). We give an overview in the field and evaluate the concept of monolithic DSC further with respect to upscaling and producibility on glass substrates. We have de...

A comprehensive characterisation of an ionic liquid based electrolyte for dye-sensitised solar cells (DSSC) was performed by determination of triiodide diffusion coefficients, viscosities and photovoltaic performances. The electrolyte, consisting of 1-ethyl-3-methylimidazolium dicyanamide, 1-methyl-3-propylimidazolium iodide (MPII), and iodine, was...

A comprehensive characterization of an ionic liquid based electrolyte for dye-sensitized solar cells (DSSC) was performed by detection of triiodide diffusion coefficients, viscosities and photovoltaic performances. The electrolyte, consisting of 1-ethyl-3-methylimidazolium dicyanamide, 1-methyl-3-propylimidazolium iodide (MPII), and iodine, was exa...

The performance of dye-sensitized solar cells (DSSC) based on the propyl-methyl-imidazolium iodide (PMII) ionic liquid (IL) with and without the addition of SiO2 nanoparticles is studied. Results confirm that the presence of SiO2 nanoparticles in PMII electrolyte improves the charge transport of iodide/tri-iodide redox couple in the electrolyte and...

A new, extremely simple concept for the use of energy transfer as a means to the enhancement of light absorption and current generation in the dye solar cell (DSC) is presented. This model study is based upon a carboxy-functionalized 4-aminonaphthalimide dye (carboxy-fluorol) as donor, and (NBu4)2[Ru(dcbpy)2(NCS)2] (N719) as acceptor chromophores....

Dye solar cells have been built in a three-electrode configuration where the nanoporous TiO2 layer has been contacted additionally on the rear side by means of a thin porous layer of metal titanium. With this third electrode, it was proved that under short-circuit conditions and an illumination intensity equivalent to “1 sun”, the differences of th...

A new bichromophoric dyad based on an alkyl-functionalized aminonaphthalimide as energy-donor chromophore and [Ru(dcbpy)2(acac)]Cl (dcbpy=4,4'-dicarboxybipyridine, acac=acetylacetonato) as energy acceptor and sensitizing chromophore is synthesized. Efficient quenching of the donor-chromophore emission is observed in solution, presumably due to reso...