Publications by Paramvir Ahlawat

Crystallization of FAPbI3: Polytypes and stacking faults

Molecular dynamics simulations are performed to study the crystallization of formamidinium lead iodide. From all-atom simulations of the crystal growth process and the delta-alpha-phase transitions, we try to reveal the formation of various stack-faulted i ...

Aip Publishing2023

A universal co-solvent dilution strategy enables facile and cost-effective fabrication of perovskite photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Sandy Sanchez Alonso, Ulf Anders Hagfeldt, Dan Ren, Hong Zhang, Linfeng Pan, Paramvir Ahlawat, Anurag Krishna

Cost management and toxic waste generation are two key issues that must be addressed before the commercialization of perovskite optoelectronic devices. We report a ground-breaking strategy for eco-friendly and cost-effective fabrication of highly efficient ...

Nature Research2022

Molecular dynamics simulations of nucleation and phase transition in halide perovskites

Paramvir Ahlawat

Perovskite solar cells have emerged as the most promising cheaper photovoltaic technology. Besides solar cells, halide perovskites have a wide range of applications due to their remarkable optoelectronic properties. Starting from 3.8% in 2009, solar to the ...

EPFL2022

Methylammonium Triiodide for Defect Engineering of High-Efficiency Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Jacques-Edouard Moser, Mounir Driss Mensi, Pascal Alexander Schouwink, Felix Thomas Eickemeyer, Mathias Dankl, Ulf Anders Hagfeldt, Lukas Pfeifer

The defects present in metal halide perovskite are deleterious to both the performance and stability of photovoltaic devices. Consequently, there is an intense focus on developing defect mitigation strategies. Herein we report a facile strategy that employ ...

2021

Multimodal host–guest complexation for efficient and stable perovskite photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Ursula Röthlisberger, Felix Thomas Eickemeyer, Jovana Milic, Marko Mladenovic, Ulf Anders Hagfeldt, Hong Zhang, Dan Ren

Formamidinium lead iodide perovskites are promising light-harvesting materials, yet stabilizing them under operating conditions without compromising optimal optoelectronic properties remains challenging. We report a multimodal host–guest complexation strat ...

Nature Research2021

Nanoscale Phase Segregation in Supramolecular π-Templating for Hybrid Perovskite Photovoltaics from NMR Crystallography

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Ursula Röthlisberger, Jovana Milic, Marko Mladenovic, Ulf Anders Hagfeldt, Dominik Józef Kubicki, Yuhang Liu, Michael Allan Hope

The use of layered perovskites is an important strategy to improve the stability of hybrid perovskite materials and their optoelectronic devices. However, tailoring their properties requires accurate structure determination at the atomic scale, which is a ...

2021

A combined molecular dynamics and experimental study of two-step process enabling low-temperature formation of phase-pure α-FAPbI3

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Paramvir Ahlawat, Essa Awadh R Alharbi, Haizhou Lu

It is well established that the lack of understanding the crystallization process in a two-step sequential deposition has a direct impact on efficiency, stability, and reproducibility of perovskite solar cells. Here, we try to understand the solid-solid ph ...

2021

Organic Spacers in 2D Perovskites: General Trends and Structure-Property Relationships from Computational Studies

Ursula Röthlisberger, Marko Mladenovic, Ariadni Boziki, Mathias Dankl, Paramvir Ahlawat, Farzaneh Jahanbakhshi

Addition of large organic molecules to halide perovskites has been shown to provoke dimensionality reduction and formation of two-dimensional phases that demonstrate improved long-term stabilities. Optoelectronic properties of the resulting 2D layered pero ...

WILEY-V C H VERLAG GMBH2021

Naphthalenediimide/Formamidinium-Based Low-Dimensional Perovskites

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Ursula Röthlisberger, Jacques-Edouard Moser, Jovana Milic, Pascal Alexander Schouwink, Marko Mladenovic, Dominik Józef Kubicki, Paramvir Ahlawat

Low-dimensional hybrid perovskites have emerged as promising materials for optoelectronic applications. Although these materials have already demonstrated enhanced stability as compared to their three-dimensional perovskite analogues, their functionality h ...

2021

Vapor-assisted deposition of highly efficient, stable black-phase FAPbI(3) perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Ursula Röthlisberger, Wolfgang Richard Tress, Likai Zheng, Felix Thomas Eickemeyer, Ulf Anders Hagfeldt, Yuhang Liu, Zaiwei Wang

Mixtures of cations or halides with FAPbI(3) (where FA is formamidinium) lead to high efficiency in perovskite solar cells (PSCs) but also to blue-shifted absorption and long-term stability issues caused by loss of volatile methylammonium (MA) and phase se ...

American Association for the Advancement of Science2020