Publications de Iwan Zimmermann

Charge Extraction and Recombination Dynamics of CdSe/CdTe Solar Cells Studied with Transient Photovoltage/Photocurrent Techniques

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Lei Chen

Significant advancements have been made in the development of high-performance cadmium telluride (CdTe)-based thin film solar cells. However, studies examining the transient excited-state charge dynamics, which determine the final steady-state device perfo ...

IEEE2023

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

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

2021

Hole-Transporting Materials for Perovskite Solar Cells Employing an Anthradithiophene Core

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Inés Garcia Benito, Hiroyuki Kanda

A decade after the report of the first efficient perovskite-based solar cell, development of novel hole-transporting materials (HTMs) is still one of the main topics in this research field. Two of the main advance vectors of this topic lie in obtaining mat ...

AMER CHEMICAL SOC2021

Nanoscale Mass-Spectrometry Imaging of Grain Boundaries in Perovskite Semiconductors

Mohammad Khaja Nazeeruddin, Paul Gratia, Tom Theodorus Antonius Lummen, Iwan Zimmermann, Hiroyuki Kanda

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 ...

2020

Development of an inorganic cesium carbonate-based electron transport material for a 17% power conversion efficiency perovskite solar cell device

Mohammad Khaja Nazeeruddin, Tom Theodorus Antonius Lummen, Iwan Zimmermann, Brahim Aissa

A low-temperature solution process technique is employed to develop an inorganic cesium carbonate (Cs2CO3) as an electron transport material for inorganic-organic hybrid double cation (FAPbI(3))(0.85)(MAPbBr(3))(0.15) perovskite solar cells, as an alternat ...

2020

Surface, Interface, and Bulk Electronic and Chemical Properties of Complete Perovskite Solar Cells: Tapered Cross-Section Photoelectron Spectroscopy, a Novel Solution

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Thomas Mayer

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 analyze these properties. However, the information d ...

AMER CHEMICAL SOC2020

Tapered Cross-Section Photoelectron Spectroscopy of State-of-the-Art Mixed Ion Perovskite Solar Cells: Band Bending Profile in the Dark, Photopotential Profile Under Open Circuit Illumination, and Band Diagram

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Thomas Mayer

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. ...

WILEY-V C H VERLAG GMBH2020

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

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, Javier Urieta Mora

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

Hole transporting materials for perovskite solar cells and a simple approach for determining the performance limiting factors

Mohammad Khaja Nazeeruddin, Tom Theodorus Antonius Lummen, Iwan Zimmermann

The synthesis and characterization of three novel HTMs with different highest occupied molecular orbital (HOMO) energy levels and their performances in MAPbI(3)-based devices in comparison with Spiro-OMeTAD is reported. Without systematic optimization, the ...

Royal Society of Chemistry2020

CuSCN as Hole Transport Material with 3D/2D Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Iwan Zimmermann

We report stable perovskite solar cells having 3D/2D perovskite absorber layers and CuSCN as an inorganic hole transporting material (HTM). (Phenylethyl)ammonium (PEA) and [(4-fluorophenyl)ethyl]ammonium (FPEA) have been chosen as 2D cations, creating thin ...

AMER CHEMICAL SOC2020

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

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

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

Non‐Planar and Flexible Hole‐Transporting Materials from Bis‐Xanthene and Bis‐Thioxanthene Units for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Giulia Grancini

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 ...

Wiley-VHCA AG2019

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

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

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

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

Mohammad Khaja Nazeeruddin, Tom Theodorus Antonius Lummen, Iwan Zimmermann, Javier Urieta Mora

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

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

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Giulia Grancini, Inés Garcia Benito, Javier Urieta Mora

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

Effect of annealing temperature on the performance of printable carbon electrodes for perovskite solar cells

Mohammad Khaja Nazeeruddin, Iwan Zimmermann, Zubair Ahmad

Perovskite solar cells (PSCs) with mesoporous TiO2 electron transport layers have reached > 22% efficiency at laboratory scale ( < 1 cm(2)), however, these layers are fabricated using spin-coating, which is not conducive to large-scale or high throughput f ...

ELSEVIER SCIENCE BV2019

Lead and HTM Free Stable Two-Dimensional Tin Perovskites with Suitable Band Gap for Solar Cell Applications

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

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 dem ...

Wiley-VCH Verlag GmbH2019

Improved efficiency and reduced hysteresis in ultra-stable fully printable mesoscopic perovskite solar cells through incorporation of CuSCN into the perovskite layer

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

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 larger modules required for the commercialization of the perovskite photovoltaic te ...

Royal Society of Chemistry2019

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

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

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