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Mohammad Ibrahim Dar

Cette personne n’est plus à l’EPFL

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Publications associées (65)

Halide Versus Nonhalide Salts: The Effects of Guanidinium Salts on the Structural, Morphological, and Photovoltaic Performances of Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Simone Meloni, Neha Arora

The impacts of halide and nonhalide sources of guanidinium cations, including guanidinium chloride (GCl) ((NH2)(3)CCl) and guanidinium thiocyanate (GTC) ((NH2)(3)CSCN), are comparatively analyzed on the structural, morphological, and photophysical properti ...

WILEY-V C H VERLAG GMBH2019

Supramolecular Engineering for Formamidinium-Based Layered 2D Perovskite Solar Cells: Structural Complexity and Dynamics Revealed by Solid-State NMR Spectroscopy

Michael Graetzel, Shaik Mohammed Zakeeruddin, Amita Ummadisingu, Mohammad Ibrahim Dar, Dominik Józef Kubicki, Jeong-Hyeok Im, David Lyndon Emsley, Jiyoun Seo, Yang Li, Jovana Milic, Yang Li, Marco Alejandro Ruiz Preciado

Perovskite solar cells are one of the most promising photovoltaic technologies, although their molecular level design and stability toward environmental factors remain a challenge. Layered 2D Ruddlesden-Popper perovskite phases feature an organic spacer bi ...

WILEY-V C H VERLAG GMBH2019

Thermodynamically stabilized beta-CsPbI3-based perovskite solar cells with efficiencies > 18%

Michael Graetzel, Mohammad Ibrahim Dar, Xiaoyan Wang, Yang Li, Xingyu Gao, Ying Yang

Although beta-CsPbI3 has a bandgap favorable for application in tandem solar cells, depositing and stabilizing beta-CsPbI3 experimentally has remained a challenge. We obtained highly crystalline beta-CsPbI3 films with an extended spectral response and enha ...

American Association for the Advancement of Science2019

Electrochemical Characterization of CuSCN Hole-Extracting Thin Films for Perovskite Photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ladislav Kavan, Mohammad Ibrahim Dar, Neha Arora

CuSCN thin films (optimized previously for perovskite photovoltaics) are deposited on glass, F:SnO2 (FTO), Au, glass-like carbon (GC), and reduced graphene oxide (rGO). They exhibit capacitive charging in an electrochemical window from ca. -0.3 to 0.2 V vs ...

AMER CHEMICAL SOC2019

Hydrothermally processed CuCrO2 nanoparticles as an inorganic hole transporting material for low-cost perovskite solar cells with superior stability

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Yuhang Liu, Seckin Akin

Despite the impressive photovoltaic performances of perovskite solar cells (PSCs) with a power conversion efficiency (PCE) beyond 22%, intensive studies are still required to overcome ongoing issues such as cost, stability, and hysteresis. Here, for the fi ...

Royal Society of Chemistry2018

Reduced Graphene Oxide as a Stabilizing Agent in Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Neha Arora, Jovana Milic

One of the most challenging obstacles to commercialization of perovskite solar cells (PSCs) is their instability toward environmental conditions. An emerging solution to overcome these challenges relies on graphene-based composites, in particular, solution ...

WILEY2018

Dedoping of Lead Halide Perovskites Incorporating Monovalent Cations

Mojtaba Abdi Jalebi, Mohammad Ibrahim Dar

2018

Influence of the Nature of A Cation on Dynamics of Charge Transfer Processes in Perovskite Solar Cells

Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Neha Arora, Pankaj Kumar Yadav

2018

High Open Circuit Voltage for Perovskite Solar Cells with S,Si-Heteropentacene-Based Hole Conductors

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Amaresh Mishra, Neha Arora

High photovoltage in perovskite solar cells (PSCs) can be achieved by designing new hole transporting materials (HTMs) with relatively deeper energy levels of the highest occupied molecular orbital (HOMO). Here, we report on the synthesis of a new heteroac ...

WILEY-V C H VERLAG GMBH2018

Insights about the Absence of Rb Cation from the 3D Perovskite Lattice: Effect on the Structural, Morphological, and Photophysical Properties and Photovoltaic Performance

Michael Graetzel, Shaik Mohammed Zakeeruddin, Silvia Binet, Gwénolé Jean Jacopin, Mohammad Ibrahim Dar, Neha Arora, Ryusuke Uchida

Efficiencies >20% are obtained from the perovskite solar cells (PSCs) employing Cs+ and Rb+ based perovskite compositions; therefore, it is important to understand the effect of these inorganic cations specifically Rb+ on the properties of perovskite struc ...

WILEY-V C H VERLAG GMBH2018

Kinetics of Ion-Exchange Reactions in Hybrid Organic-Inorganic Perovskite Thin Films Studied by In Situ Real-Time X-ray Scattering

Michael Graetzel, Mohammad Ibrahim Dar, Neha Arora

The exchange of ions in hybrid organic inorganic perovskites with the general formula APbX(3) (A = MA, FA; X = I, Cl, Br) is studied in five different systems using in situ real-time grazing incident X-ray diffraction (GIXD). In systems where the organic c ...

AMER CHEMICAL SOC2018

Inorganic hole conductor based perovskite photoelectric conversion device with high operational stability at long term

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Neha Arora

The invention relates to an optoelectronic and/or photoelectrochemical device comprising a conductive support layer, n-type semiconductor, a sensitizer or light-absorber layer, a hole transporting layer, a spacer layer and a back contact, wherein the n-typ ...

2018

Electron-Affinity-Triggered Variations on the Optical and Electrical Properties of Dye Molecules Enabling Highly Efficient Dye-Sensitized Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Péter Kalman Péchy, Ulf Anders Hagfeldt, Yiming Cao, Marko Stojanovic, Mohammad Ibrahim Dar, Yasemin Saygili, Weiwei Zhang, Yuhang Liu

The synthesis, characterization, and photovoltaic performance of a series of indacenodithiophene (IDT)-based D--A organic dyes with varying electron-accepting units is presented. By control of the electron affinity, perfectly matching energy levels were ac ...

Wiley-VCH Verlag GmbH2018

Guanidinium cations roles in perovskites solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Neha Arora

AMER CHEMICAL SOC2018

High photovoltage in perovskite solar cells: New physical insights from the ultrafast transient absorption spectroscopy

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Marius Franckevicius, Neha Arora

To understand the cause of the high open circuit photovoltage (VOC) achieved by todays' state of the art perovskite solar cells (PSCs), we examine formamidinium lead bromide CH(NH2)(2)PbBr3 films by ultrafast transient absorption spectroscopy (TAS). By usi ...

Elsevier2017

Function Follows Form: Correlation between the Growth and Local Emission of Perovskite Structures and the Performance of Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Gwénolé Jean Jacopin, Mohammad Ibrahim Dar, Neha Arora

Understanding the relationship between the growth and local emission of hybrid perovskite structures and the performance of the devices based on them demands attention. This study investigates the local structural and emission features of CH3NH3PbI3, CH3NH ...

Wiley-Blackwell2017

Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Norman Pellet, Mohammad Ibrahim Dar, Neha Arora

Perovskite solar cells (PSCs) with efficiencies greater than 20% have been realized only with expensive organic hole-transporting materials. We demonstrate PSCs that achieve stabilized efficiencies exceeding 20% with copper(I) thiocyanate (CuSCN) as the ho ...

American Association for the Advancement of Science2017

High performance carbon-based printed perovskite solar cells with humidity assisted thermal treatment

Michael Graetzel, Shaik Mohammed Zakeeruddin, Syed Ghufran Hashmi, Mohammad Ibrahim Dar

We report humidity assisted thermal exposure (HTE) as a post-treatment method for carbon based printed perovskite solar cells (CPSCs). The method does not only improve the interfaces of different layers of the printed stack, but also provides a pathway to ...

Royal Society of Chemistry2017

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Michael Graetzel, Mojtaba Abdi Jalebi, Mohammad Ibrahim Dar

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical properties. The possibility of doping was investigated by adding monovalent cation halides with simil ...

Journal Of Visualized Experiments2017

The Role of Rubidium in Multiple-Cation-Based High-Efficiency Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Fabrizio Giordano, Neha Arora, Essa Awadh R Alharbi, Pankaj Kumar Yadav

Perovskite solar cells (PSCs) based on cesium (Cs)- and rubidium (Rb)-containing perovskite films show highly reproducible performance; however, a fundamental understanding of these systems is still emerging. Herein, this study has systematically investiga ...

Wiley-Blackwell2017

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