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Iwan Zimmermann

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Related publications (39)

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Intrinsic Halide Segregation at Nanometer Scale Determines the High Efficiency of Mixed Cation/Mixed Halide Perovskite Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Kevin Sivula, Iwan Zimmermann, Giulia Grancini, Yonghui Lee, Paul Gratia, Xavier Adrian Jeanbourquin

Compositional engineering of a mixed cation/mixed halide perovskite in the form of (FAP-bI(3))(0.85)(MAPbBr(3))(0.15) is one of the most effective strategies to obtain record-efficiency perovskite solar cells. However, the perovskite self-organization upon ...

2016

Tetrasubstituted Thieno[3,2-b]thiophenes as Hole-Transporting Materials for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Tom Theodorus Antonius Lummen, Iwan Zimmermann, Inés Garcia Benito

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 ...

2020

Bis-Tridentate-Cyclometalated Ruthenium Complexes with Extended Anchoring Ligand and Their Performance in Dye-Sensitized Solar Cells

Mohammad Khaja Nazeeruddin, Peng Wang, Iwan Zimmermann, Sadig Aghazada, Yameng Ren

2018

Isomerism effect on the photovoltaic properties of benzotrithiophene-based hole-transporting materials

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Inés Garcia Benito

Engineering of inorg.-org. 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 ...

Royal Society of Chemistry2017

Insight into Lipopolysaccharide Translocation by Cryo-EM structures of a LptDE Transporter in Complex with Pro-Macrobodies

Henning Paul-Julius Stahlberg, Iwan Zimmermann, Dongchun Ni, Denis Bucher

2021

Water-Repellent Low-Dimensional Fluorous Perovskite as Interfacial Coating for 20% Efficient Solar Cells

Mohammad Khaja Nazeeruddin, Yi Zhang, Andreas Stephan Lesch, Iwan Zimmermann, Giulia Grancini, Kyung Taek Cho

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 exp ...

American Chemical Society (ACS)2018

Fashioning Fluorous Organic Spacers for Tunable and Stable Layered Hybrid Perovskites

Mohammad Khaja Nazeeruddin, Andreas Stephan Lesch, Iwan Zimmermann, Giulia Grancini, Valentin Ianis Emmanuel Queloz, Inés Garcia Benito

2018

The Many Faces of Mixed Ion Perovskites: Unraveling and Understanding the Crystallization Process

Mohammad Khaja Nazeeruddin, Kevin Sivula, Jun Ho Yum, Iwan Zimmermann, Paul Gratia

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 hex ...

Amer Chemical Soc2017

Exploration of bis(arylimidazole) Iridium picolinate complexes

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Giulia Grancini, Natalia Gasilova, Aron Joel Huckaba, Sadig Aghazada

2017

High-Efficiency Perovskite Solar Cells Using Molecularly Engineered, Thiophene-Rich, Hole-Transporting Materials: Influence of Alkyl Chain Length on Power Conversion Efficiency

Mohammad Khaja Nazeeruddin, Giulia Grancini, Iwan Zimmermann, Paul Gratia

The synthesis and characterization of a series of novel small-molecule holetransporting 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 ha ...

Wiley-V C H Verlag Gmbh2017

Dibenzoquinquethiophene- and Dibenzosexithiophene-Based Hole-Transporting Materials for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Tom Theodorus Antonius Lummen, Iwan Zimmermann

Fused oligothiophene-based pi-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 pi-conjugated framework, which endows ...

2019

Atomic Layer-Deposited Aluminum Oxide Hinders Iodide Migration and Stabilizes Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Iwan Zimmermann

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 surf ...

ELSEVIER2020

Benzotrithiophene-Based Hole-Transporting Materials for 18.2% Perovskite Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Cristina Roldán Carmona, Paul Gratia, Sadig Aghazada, Inés Garcia Benito

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 wer ...

Wiley-VCH Verlag GmbH2016

Unsymmetrical and Symmetrical Zn(II) Phthalocyanines as Hole-Transporting Materials for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Yi Zhang, Sanghyun Paek, Iwan Zimmermann, Kyung Taek Cho

2018

High efficiency methylammonium lead triiodide perovskite solar cells: the relevance of non-stoichiometric precursors

Michael Graetzel, Mohammad Khaja Nazeeruddin, Peng Gao, Iwan Zimmermann, Giulia Grancini, Cristina Roldán Carmona, Peng Gao, Paul Gratia

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 1 ...

Royal Soc Chemistry2015

Ionic dipolar switching hinders charge collection in perovskite solar cells with normal and inverted hysteresis

Mohammad Khaja Nazeeruddin, Tom Theodorus Antonius Lummen, Kyung Taek Cho, Iwan Zimmermann, Sadig Aghazada

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 we ...

2019

Saddle-like, π-conjugated, cyclooctatetrathiophene-based, hole-transporting material for perovskite solar cells

Mohammad Khaja Nazeeruddin, Giulia Grancini, Iwan Zimmermann, Inés Garcia Benito

A flexible, saddle-like, π-conjugated skeleton composed of four fused thiophene rings forming a cyclooctatetrathiophene (CoTh) with four triphenylamines (CoTh-TTPA) is presented as a hole-transporting material (HTM) for perovskite solar cells. The new HTM ...

Royal Society of Chemistry2019

Effective Preparation of Nanoscale CH3NH3PbI3 Perovskite Photosensitizers for Mesoporous TiO2-Based Solar Cells by Successive Precursor Layer Adsorption and Reaction Process

Mohammad Khaja Nazeeruddin, Tom Theodorus Antonius Lummen, Yonghui Lee, Sanghyun Paek, Aron Joel Huckaba, Kyung Taek Cho, Iwan Zimmermann, Hobeom Kim, So-Min Yoo, Alexandre Vincent Laurent Chenu, Michael Gullberg

Nanoscale CH3NH3PbI3 perovskite sensitizers are grown by delivering each precursor successively onto the surface of mesoporous (meso) TiO2 electrodes. Using Pb(NO3)(2) ions as a lead(II) source and CH3NH3I (MAI) for methylammonium and iodide sources, repet ...

2020

Enhanced TiO2/MAPbI(3) Electronic Coupling by Interface Modification with PbI2

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Giulia Grancini, Cristina Roldán Carmona, Paul Gratia

Amer Chemical Soc2016