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Mohammad Ibrahim Dar

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Related publications (63)

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Origin of unusual bandgap shift and dual emission in organic-inorganic lead halide perovskites

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Mohammad Ibrahim Dar, Gwénolé Jean Jacopin, Neha Arora, Simone Meloni, Ariadni Boziki

Emission characteristics of metal halide perovskites play a key role in the current widespread investigations into their potential uses in optoelectronics and photonics. However, a fundamental understanding of the molecular origin of the unusual blueshift ...

2016

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, Neha Arora, Simone Meloni

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

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

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

Quantifying Stabilized Phase Purity in Formamidinium-Based Multiple-Cation Hybrid Perovskites

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Neha Arora, Thomas Paul Baumeler

A promising approach for the production of highly efficient and stable hybrid perovskite solar cells is employing mixed-ion materials. Remarkable performances have been reached by materials comprising a stabilized mixture of methylammonium (MA(+)) and form ...

2021

Charge extraction via graded doping of hole transport layers gives highly luminescent and stable metal halide perovskite devices

Michael Graetzel, Mohammad Ibrahim Dar, Mojtaba Abdi Jalebi

One source of instability in perovskite solar cells (PSCs) is interfacial defects, particularly those that exist between the perovskite and the hole transport layer (HTL). We demonstrate that thermally evaporated dopant-free tetra-cene (120 nm) on top of t ...

2019

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

Michael Graetzel, Shaik Mohammed Zakeeruddin, 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

A wire shaped coaxial photovoltaic solar cell

Michael Graetzel, Mohammad Khaja Nazeeruddin, Mohammad Ibrahim Dar

A wire shaped coaxial photovoltaic solar cell comprising: a conductive core wire shaped support (401), a nanostructured semiconductor scaffold layer (402), one or more successive perovskite layers (403), an optionally provided hole transporting material la ...

2017

Weakly Conjugated Hybrid Zinc Porphyrin Sensitizers for Solid-State Dye-Sensitized Solar Cells

Mohammad Khaja Nazeeruddin, Christian Ludwig, Mohammad Ibrahim Dar, Kasparas Rakstys, Peng Qin

Molecularly engineered weakly conjugated hybrid porphyrin systems are presented as efficient sensitizers for solid-state dye-sensitized solar cells. By incorporating the quinolizino acridine and triazatruxene based unit as the secondary light-harvester as ...

Wiley-Blackwell2016

Reduced Graphene Oxide as a Stabilizing Agent in Perovskite Solar Cells

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

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

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

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

Photoanode Based on (001)-Oriented Anatase Nanoplatelets for Organic-Inorganic Lead Iodide Perovskite Solar Cell

Michael Graetzel, Mohammad Khaja Nazeeruddin, Mohammad Ibrahim Dar

The methodology adopted for the preparation of perovskites plays a critical role in achieving high efficiency. Toward this direction, various strategies have been adopted to achieve a rational control over the growth of the perovskite layer for the fabrica ...

American Chemical Society2014

Perovskite Solar Cells with 12.8% Efficiency by Using Conjugated Quinolizino Acridine Based Hole Transporting Material

Michael Graetzel, Mohammad Khaja Nazeeruddin, Mohammad Ibrahim Dar, Sanghyun Paek, Norman Pellet, Peng Qin

A low band gap quinolizino acridine based molecule was designed and synthesized as new hole transporting material for organic-inorganic hybrid lead halide perovskite solar cells. The functionalized quinolizino acridine compound showed an effective hole mob ...

American Chemical Society2014

New Strategies for Defect Passivation in High-Efficiency Perovskite Solar Cells

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

Lead halide perovskite solar cells now show excellent efficiencies and encouraging levels of stability. Further improvements in performance require better control of the trap states which are considered to be associated with vacancies and defects at crysta ...

WILEY-V C H VERLAG GMBH2019

A Novel Oligomer as a Hole Transporting Material for Efficient Perovskite Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Peng Gao, Mohammad Ibrahim Dar, Peng Gao, Nicolas Tétreault, Peng Qin

(Figure Presented) A polytriarylamine-based oligomer is reported as a hole transporting material and its application in solid-state CH3NH3PbI3 based heterojunction solar cells is described. It yields a power conversion efficiency of 12.0% under 99.6 mW cm- ...

Wiley-VCH Verlag Berlin2015

Bifunctional Organic Spacers for Formamidinium-Based Hybrid Dion-Jacobson Two-Dimensional Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Peng Wang, Mohammad Ibrahim Dar, Yuhang Liu, Jovana Milic, Jiyoun Seo, Amita Ummadisingu, Yang Li, Hui-Seon Kim, Jeong-Hyeok Im

Three-dimensional (3D) perovskite materials display remarkable potential in photovoltaics owing to their superior solar-to-electric power conversion efficiency, with current efforts focused on improving stability. Two-dimensional (2D) perovskite analogues ...

AMER CHEMICAL SOC2019

Cyclopentadithiophene-Based Hole-Transporting Material for Highly Stable Perovskite Solar Cells with Stabilized Efficiencies Approaching 21%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Gwénolé Jean Jacopin, Yuhang Liu, Neha Arora, Ryusuke Uchida, Seckin Akin

There is an urge to develop new hole-transporting materials (HTMs) for perovskite solar cells (PSCs), which can yield comparable power conversion efficiencies (PCEs) yet mitigate the issue of stability associated with the state-of-the-art HTM Spiro-MeOTAD. ...

AMER CHEMICAL SOC2020

Understanding the Impact of Bromide on the Photovoltaic Performance of CH3NH3PbI3 Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Mohammad Ibrahim Dar, Thomas Moehl, Neha Arora, Mojtaba Abdi Jalebi

An optimum amount of lead bromide (1%) can enhance the power conversion efficiency of CH3NH3PbI3-xBrx (where x approximate to 0) devices from 14.7% to 16.9% without altering the bandgap of the perovskite material. ...

Wiley-V C H Verlag Gmbh2015

Atomistic Mechanism of the Nucleation of Methylammonium Lead Iodide Perovskite from Solution

Michael Graetzel, Ursula Röthlisberger, Mohammad Ibrahim Dar, Paramvir Ahlawat

In the ongoing intense quest to increase the performance of perovskite solar cells, optimizing the morphology of perovskite material has become imperative to achieve high power conversion efficiencies. Despite the fact that nucleation plays a key role in c ...

ACS2019

Strong Photocurrent Amplification in Perovskite Solar Cells with a Porous TiO2 Blocking Layer under Reverse Bias

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Thomas Moehl, Fabrizio Giordano, Yonghui Lee, Konrad Domanski, Leo-Philipp Heiniger, Jeong-Hyeok Im

We investigate two different types of TiO2 blocking layer (BL) deposition techniques commonly used in solid-state methylammonium lead triiodide perovskite (MaPbI(3))-based solar cells. Although these BLs lead to similar photovoltaic device performance, the ...

Amer Chemical Soc2014

Intrinsic and Extrinsic Stability of Formamidinium Lead Bromide Perovskite Solar Cells Yielding High Photovoltage

Shaik Mohammed Zakeeruddin, Mohammad Ibrahim Dar, Gwénolé Jean Jacopin, Fabrizio Giordano, Neha Arora, Norman Pellet, Mojtaba Abdi Jalebi

We report on both the intrinsic and the extrinsic stability of a formamidinium lead bromide [CH(NH2)(2)PbBr3 = FAPbBr(3)] perovskite solar cell that yields a high photovoltage. The fabrication of FAPbBr(3) devices, displaying an outstanding photo voltage o ...

American Chemical Society2016