Iwan Zimmermann

Iwan Zimmermann
Ile-de-France Photovoltaic Institute | IPVF

About

93
Publications
22,649
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3,835
Citations
Citations since 2017
49 Research Items
3649 Citations
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800

Publications

Publications (93)
Article
Development of industrially relevant thin-film deposition processes is a necessity for upscaling the perovskite solar cell technology to commercial product-level. This work reports on a sequential deposition method for state-of-the art triple cation perovskite by slot-die coating. During this two-step process, first, a layer of lead iodide mixed wi...
Article
Full-text available
Slot-die coating is a promising technique paving the way for large-area perovskite deposition and commercially relevant solar devices fabrication with sharp control over the thickness and material composition. However, before transferring perovskite solar cells technology to commercial applications, it is required to develop ink formulations guaran...
Article
Incorporation of alkali metals such as Cs+, Rb+, and K+ into hybrid organic–inorganic halide lead perovskites (HOIPs) generally improves the optoelectronic properties of HOIPs. However, it is still uncertain how alkali metals interact and distribute within the HOIPs. There is also a struggle in finding a technique for nanometer-scale structural and...
Article
The surface, interface, and bulk properties are a few of the most critical factors that influence the performance of perovskite solar cells. The photoelectron spectroscopy (PES) is used as a technique to analyses these properties. However, the information depth of PES is limited to 10-20 nm, which makes it not suitable to study the complete devices...
Article
Full-text available
Iodide migration causes degradation of the perovskite solar cells. Here, we observe the direct migration of iodide into the hole-transport layer in a device. We demonstrate that ultrathin room temperature atomic layer-deposited Al2O3 on the perovskite surface very effectively hinders the migration. The perovskite-Al2O3 interface enables charge tran...
Article
Full-text available
The purpose of this article is twofold. On the one hand the method of spacial resolved photoemission spectroscopy on small angle tapered cross-sections (TCS) of complete devices is introduced to analyze simultaneously the chemical and electronic structure. On the other hand, a specific working principle of the analyzed cell type is revealed. Solar...
Article
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Nanoscale CH3NH3PbI3 perovskite sensitizers are grown step‐by‐step by delivering each precursor successively onto the surface of mesoporous (meso) TiO2 electrode. Using Pb(NO3)2 ions as a lead(II) source and CH3NH3I (MAI) for methylammonium and iodide sources, repetitive cycles of the two dipping steps are successful in growing few nanometer‐sized...
Article
The synthesis and characterization of three novel HTMs with different highest occupied molecular orbital (HOMO) energy levels and their performances in MAPbI3-based devices in comparison with Spiro-OMeTAD is reported. Without systematic optimization, the HTMs performed well. The devices delivered fill factors comparable to the one with Spiro-OMeTAD...
Article
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We report stable perovskite solar cells having 3D/2D perovskite absorber layers and CuSCN as an inorganic hole transporting material (HTM). Phenylethylammonium (PEA) and 4-fluoro-phenylethylammonium (FPEA) have been chosen as 2D cations, creating thin layers of [PEA2PbI4] or [FPEA2PbI4] on top of the 3D perovskite. The 2D perovskite as an interfaci...
Article
Three hole-transporting materials (HTMs) were prepared following a straightforward synthetic route by cross-linking arylamine-based ligands with a simple thieno[3,2-b]thiophene (TbT) core. The novel HTMs were fully characterized with standard techniques to gain insight into their optical and electrochemical properties and were incorporated in solut...
Article
A flexible, saddle-like, π-conjugated skeleton containing four fused thiophene rings forming a cyclooctatetrathiophene (CoTh), endowed with four triphenylamines (CoTh-TTPA), is presented as hole-transporting material (HTM) for perovskite solar cells. The new HTM shows bright red color stemming from the direct conjugation between the TPA groups and...
Article
Full-text available
Drift-diffusion modeling of the ionic dipole switching from the measurement of fast scanned and long pre-biased electrical response is proposed as a novel protocol for evaluation of limit hysteretic effects in perovskite solar cells. Up to eight systems were measured including CH3NH3PbI3 , Cs0.1FA0.74MA0.13PbI2.48Br0.39 and FA0.83MA0.17 Pb1.1Br0.22...
Article
Two new hole‐transporting materials (HTMs), BX‐OMeTAD and BTX‐OMeTAD, based on xanthene and thioxanthene units, respectively, and bearing p‐methoxydiphenylamine peripheral groups are presented for their use in perovskite solar cells (PSCs). The novelty of the newly designed molecules relies on the use of a single carbon−carbon bond “C−C” as a linke...
Article
Fully-printable hole transport layer free mesoscopic perovskite solar cells have proven excellent long-term stability and are therefore promising candidates for scale-up to lager modules required for the commercialization of the perovskite photovoltaic technology. In this work the imbalanced charge extraction resulting from relatively thick device...
Article
Fused oligothiophene-based -conjugated organic derivatives have been widely used in electronic devices. In particular, two-dimensional (2D) heteroarenes offer the possibility of broadening the scope by extending the -conjugated framework, which endows enhanced charge transport properties due to the potential intermolecular ‒ stacking. Here, the syn...
Article
Perovskite solar cells with mesoporous TiO2 electron transport layers have reached >22% efficiency at laboratory scale (<1 cm2), however, these layers are fabricated using spin-coating, which is not conducive to large-scale or high throughput fabrication. Alternatively, screen printing, slot die coating and spray pyrolysis techniques are very suita...
Article
Organic‐inorganic hybrid perovskites have attracted great attention over the last few years as potential light‐harvesting materials for efficient and cost‐effective solar cells. However, the use of lead iodide in state‐of‐the‐art perovskite devices may demonstrate an obstacle for future commercialization due to toxicity of lead. Herein we report on...
Article
Organic‐inorganic hybrid perovskites have attracted great attention over the last few years as potential light‐harvesting materials for efficient and cost‐effective solar cells. However, the use of lead iodide in state‐of‐the‐art perovskite devices may demonstrate an obstacle for future commercialization due to toxicity of lead. Herein we report on...
Article
Two dimensional (2D) organic-inorganic hybrid perovskites have recently attracted enormous attention due to their higher environmental stability with respect to three-dimensional (3D) perovskites and larger structural tunability. The layered structure relaxes constraints on the dimensions of the organic cations that alternate the inorganic sheets,...
Article
Full-text available
By two‐step sequential Pb2+ adsorption and reaction with methylammonium‐iodide (MAI) or ‐bromide (MABr) at a low concentration level of 0.06–0.10 m over mesoporous TiO2 or ZrO2 film, a well‐defined nanoscale CH3NH3PbI3 (MAPbI3) photosensitizer or CH3NH3PbBr3 (MAPbBr3) light emitter could be prepared in situ, respectively in a reproducible and atom‐...
Article
Hybrid perovskite solar cells have been capturing an enormous research interest in the energy sector due to their extraordinary performances and ease of fabrication. However, low device lifetime, mainly due to material and device degradation upon water exposure, challenges their near-future commercialization. Here, we synthesized a new fluorous org...
Article
Full-text available
Three new star‐shaped hole‐transporting materials (HTMs) incorporating benzotripyrrole, benzotrifuran, and benzotriselenophene central cores endowed with three‐armed triphenylamine moieties (BTP‐1, BTF‐1, and BTSe‐1, respectively) are designed, synthesized, and implemented in perovskite solar cells (PSCs). The impact that the heteroatom‐containing...
Article
Full-text available
In article number 1801734, Agustín Molina‐Ontoria, Enrique Ortí, Nazario Martín, Mohammad Khaja Nazeeruddin, and co‐workers conduct a systematic study on how heteroatoms in the central scaffold of star‐shaped hole‐transporting materials affect the photovoltaic efficiency of perovskite solar cells. Chalcogenide‐based derivatives achieve excellent pe...
Article
An unsymmetrical zinc phthalocyanine with one carboxyl and three tert-butyl groups (TT1) and a symmetrical zinc phthalocyanine with four tert-butyl groups (TT0) are employed as hole transporting materials (HTMs) in mixed-ion perovskite [HC(NH2)2]0.1(CH3NH3)0.9PbI3 solar cells. The optical and electrochemical data of TT1 and TT0 exhibit appropriate...
Article
Thiophene-based p-type molecules are being extensively investigated and employed in opto-electrical devices due to their intriguing semiconducting properties. Herein, we report the synthesis and characterization of 4H-cyclopenta[1,2-b:5,4-b']dithiophene-based core, having methoxy-substituted triphenylamine side arms as donor groups. These rationall...
Article
Full-text available
The straightforward synthesis and photophysical properties of a new series of heteroleptic iridium(III) bis(2-arylimidazole) picolinate complexes are reported. Each complex has been characterized by nuclear magnetic resonance, UV–vis, cyclic voltammetry, and photoluminescent angle dependency, and the emissive properties of each are described. The p...
Article
Full-text available
The ubiquitous hysteresis in the current-voltage characteristic of perovskite solar cells (PSCs) interferes in a proper determination of the diode ideality factor (n), a key parameter commonly adopted to analyze recombination mechanisms. An alternative way of determining n is by measuring the voltage variation of the ac resistances in conditions of...
Article
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The development of highly efficient hole transporting materials (HTMs) for perovskite solar cells (PSCs) is still one of the most thrilling research subjects in the development of this emerging photovoltaic technology. Inner ring engineering of the aromatic core of new HTMs –consisting in three fused rings endowed with four triarylamine units– reve...
Article
Ruthenium polypyridine complexes with six-membered chelating rings have recently received significant attention due to their broad absorption spectra and outstanding photophysical characteristics. In this work we present the synthesis and characterization of three new heteroleptic bis-tridentate cyclometalated ruthenium complexes, i. e. 1 a, 2 a, a...
Conference Paper
Full-text available
CuI and CuSCN as Hole Transport Materials for Perovskite Solar Cells Vinod E. Madhavan1*, Ahmer Ali Bozdar Baloch1, Afsal Manekkathodi1, Dhanasekaran Thirunvukkaarasu1, I. Zimmermann2, C. Roldán- Carmona2, G. Grancini2, M. Buffiere1, Mohammad Khaja Nazeeruddin2, A. Belaidi1 and Nouar Tabet1 1 Qatar Environment and Energy Research Institute, Hamad B...
Article
Full-text available
Understanding the crystallization process of organic-inorganic halide perovskites is of paramount importance for fabrication of reproducible and efficient perovskite solar cells. We report for the first time on the discovery and interplay of ubiquitous hexagonal polytypes (6H and 4H) during the crystallization process of mixed ion perovskite, i.e....
Article
In the search of new ligand environment for the ruthenium(II) complexes with pyridine-type ligands, we developed seven new cyclometalated ruthenium complexes with N-heterocyclic carbenes (NHCs). In a two-step procedure, we synthesized complexes with the general formula [Ru(NHC^C)(bpyR2)2](PF6), where NHC^C is a bidentate ligand coordinating with th...
Article
Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are sti...
Article
The structural and electrochemical properties of a quaternary layered compound with elemental composition Mn2Sb3O6Cl have been investigated upon reaction with lithium in Li half cells. Operando XRD was used to investigate the potential impact of this particular layered structure on the lithiation process. Although the results suggest that the mater...
Article
Engineering of inorganic-organic lead halide perovskites for photovoltaic applications has experienced significant advances in recent years. However, the use of the relatively expensive spiro-OMeTAD as a hole-transporting material (HTM) poses a challenge due to dopant-induced degradation. Herein we introduce two new three-armed and four-armed HTMs...
Article
Full-text available
Compositional engineering of mixed cation/mixed halide perovskite in the form of (FAPbI3)0.85(MAPbBr3)0.15 is one of the most effective strategies to obtain record-efficiency perovskite solar cells. However, the perovskite self-organization upon crystallization and the final elemental distribution, paramount for device optimization, are still poorl...
Article
In this communication, we show that the mixed perovskite in the form of (FAPbI3)0.85(MAPbBr3)0.15 in combination with CuNCS as p-type hole conductor lead to over 16% power conversion efficiency under full sun illumination and yields a remarkable monochromatic incident photon-to-electron conversion efficiency of 85%. The devices displayed a short-ci...
Article
The synthesis and characterization of a series of novel small-molecule hole-transporting materials (HTMs) based on an anthra[1,2-b:4,3-b′:5,6-b′′:8,7-b′′′]tetrathiophene (ATT) core are reported. The new compounds follow an easy synthetic route and have no need of expensive purification steps. The novel HTMs are tested in perovskite solar cells and...
Article
Hybrid perovskite solar cells, with their power conversion efficiency (PCE) exceeding 22%, have been representing a revolutionary concept for future energy power generation. Although listed among the Top 10 Emerging Technologies of 2016, device longevity is the actual bottleneck for their real uptake in the market. Here we design an ultra-stable mo...
Article
The synthesis of a new series of neutral Iridium (III) bis(2-(2',4'-difluorophenylpyridine)(1-(2'-aryl)-3-methylimidazol-2-ylidene) complexes is reported. Each complex has been characterized by NMR, UV-Vis, cyclic voltammetry, and the photophysical properties deeply explored. Furthermore, two of the complexes were characterized by single crystal X-...
Article
An electrochemical and structural investigation of two transition metal oxohalides has been undertaken. As negative electrodes for Li-ion batteries, these materials exhibit a combination of both conversion and alloying reactions within the same cell, giving rise to interesting electrochemical performances. Alloying-type reactions, typically involvi...
Article
We report a combined experimental and computational investigation to elucidate the effect of PbI2 on the electronic properties of the TiO2/methylammonium lead-iodide (MAPbI3) perovskite interface. We propose that excess PbI2 from the precursor solution or from a TiO2 pre-treatment may be predominantly located at the interface with the semiconductin...
Article
Donor-π-Bridge-Donor type oligomers (D-π-D) have been studied intensively as active materials for organic optoelectronic devices. In this study, we introduce three new D-π-D type organic semiconductors incorporating thiophene or thienothiophene with two electron-rich TPA units, which can be synthesized easily from commercially available materials....
Article
New star-shaped benzotrithiophene (BTT)-based hole-transporting materials (HTM) BTT-1, BTT-2 and BTT-3 have been obtained through a facile synthetic route by crosslinking triarylamine-based donor groups with a benzotrithiophene (BTT) core. The BTT HTMs were tested on solution-processed lead trihalide perovskite-based solar cells. Power conversion e...
Article
The small-molecule hole transporting materials based on indolocarbazole core were synthesized and incorporated into perovskite solar cells, which displayed a power conversion efficiency of up to 15.24%. The investigated hole transporting materials were synthesized in three steps from commercially available and relatively inexpensive starting materi...
Article
Methylammonium lead iodide perovskite solar cells with improved performance and stability have been successfully prepared by using a non-stoichiometric PbI2:CH3NH3I ratio in the precursor solution, and yield a power conversion efficiency (PCE) of above 19% under 1 sun for the champion cell.
Article
The new copper oxo-antimony sulphate CuSb6O8(SO4)2 crystallizes in the triclinic space group P1[combining macron] with the unit cell parameters a = 5.5342(4) Å, b = 7.6706(6) Å, c = 9.2374(7) Å, α = 96.505(5)°, β = 93.818(4)°, γ = 109.733(4)° and Z = 1. The crystal structure is made up of layers stacking along [001]. The layers are charge neutral a...
Article
Full-text available
Host-guest complexes between cryptophane-A analogue with butoxy groups (cryptophane-But) and chloromethanes (chloroform, dichloromethane) were investigated in the solid state by means of magic-angle spinning (13) C NMR spectroscopy. The separated local fields method with (13) C-(1) H dipolar recoupling was used to determine the residual dipolar cou...
Article
The new compound Co2Te3(PO4)O6Cl was synthesized by chemical reactions in a sealed and evacuated silica tube. The crystal structure was solved from single crystal diffraction data and is made up by charge neutral layers. Within the layers two types of chains are made up by edge sharing [CoO6] and [CoO5Cl] polyhedra respectively. The chains are sepa...
Article
Orange single crystals of the title compound are obtained from an equimolar mixture of TeO2, FeCl3, FeCl2, Fe2O3, and (NH4)H2PO4 (evacuated silica tube, 550 °C, 70 h).
Article
The compounds Mn3(Sb2O2)(VO4)2–x(SbO3)xCl2 (x = 0.08, 0.10, and 0.13) crystallize in the triclinic space group P. The compounds were synthesized through chemical reactions at 550 °C in sealed evacuated silica tubes. The crystal structure is a three-dimensional framework structure having small channels running along [100]. The manganese oxochloride...
Article
The new compounds Mn-4(TeO3)(SiO4)X-2 (X=Br, Cl) were synthesized by solid state reactions in sealed evacuated silica tubes. The compounds crystallize in the monoclinic space group P2(1)/m with the unit cell parameters a=5.5463(3) angstrom (5.49434(7) angstrom), b= 6.4893(4) angstrom (6.44184(9) angstrom), c=12.8709(7) A (12.60451 (18) angstrom), b...
Article
Full-text available
The isostructural title compounds, {(C7H7N2)2[SnI4]} n , (1), and {(C7H5F2N2)2[SnI4]} n , (2), show a layered perovskite-type structure composed of anionic {[SnI4](2-)} n sheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-di-fluoro-benzimidazolium cations, respectively. These planar organic heterocycl...
Article
The synthesis and crystal structure of eight new layered compounds in the (Mn2+, Fe2+)-(Sb3+, Te4+)-O-(Cl, Br) system are presented. Mn5Te4O12Cl2 (1), MnSb4O6Cl2 (2), Mn2Sb3O6Cl (3), Mn9Sb8O16Cl10 (4), Fe3Sb2O4Br4 (5), Fe7Sb10O18X8 [X = Cl (6), Br (7)], and Mn7Sb10O18Br8 (8). All of the compounds are made up of charge neutral layers held together t...
Article
The new compounds Mn4(TeO3)(SiO4)X 2 (X=Br, Cl) were synthesized by solid state reactions in sealed evacuated silica tubes. The compounds crystallize in the monoclinic space group P21/m with the unit cell parameters a=5.5463(3) Å (5.49434(7) Å), b=6.4893(4) Å (6.44184(9) Å), c=12.8709(7) Å (12.60451(18) Å), β=93.559(5)° (94.1590(12)°) and Z=2 for t...
Article
The new compound Fe11(TeO3)2(TeO4)3(PO4)2O4Cl3 containing FeIII and TeIV crystallizes in the monoclinic space group C2/c with the unit cell parameters a = 20.5816(5) Å, b = 26.7506(6) Å, c = 5.03910(10) Å, β = 93.587(2)o, Z = 4. Single crystals were grown in sealed and evacuated silica tubes at 550 °C. The compound exhibits an open framework struct...
Article
Full-text available
Transparent needle like single crystals of the isostructural compounds [Sb4O7+3δX4][Zn3]1+δ(X = Cl, Br, I), δ≈ 0.2 were obtained from chemical reactions in evacuated and sealed silica tubes. First the average structure was solved in P21/n and then modulations were introduced but the model refined poorly and a lowering of the symmetry to the 3+1 dim...
Article
Full-text available
A synthetic study in the Cd-Se-O-Cl system led to formation of the new oxochloride compound Cd4(SeO3)2OCl2 via solid state reactions. The compound crystallizes in the orthorhombic space group Fmmm with cell parameters a = 7.3610(3) Å, b = 15.4936(2) Å, c = 17.5603(3) Å, Z = 8, S = 0.969, F(000) = 2800, R = 0.0185, Rw = 0.0384. Single crystal X-ray...
Article
Two new oxohalides Co4Se3O9Cl2 and Co3Se4O10Cl2 have been synthesized by solid state reactions. They crystallize in the orthorhombic space group Pnma and the monoclinic space group C2/m respectively. The crystal structure of the two compounds are made up of similar building blocks; Co4Se3O9Cl2 is made up of [CoO4Cl2], [CoO5Cl] and [SeO3] polyhedra...
Article
Three new cobalt selenite hydroxo-phosphates laying in the solid solution Co3(SeO3)3-x(PO3OH)x(H2O), with x = 0.8, x = 1.0, and x = 1.2 are reported. Single crystals were obtained by hydrothermal synthesis and the crystal structure was determined by single crystal X-ray diffraction. The structure can be described as a 3D framework having selenite a...
Article
Full-text available
A new chromium tellurite oxochloride, Cr3Te5O13Cl3, has been prepared by solid-state reaction and the crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in the non-centrosymmetric space group P212121 with the unit cell a = 4.90180(10) Å, b = 17.3394(2) Å, c = 17.5405(2) Å, Z = 4, R1 = 0.0282. The Cr(3+)...