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Yuhang Liu

Cette personne a quitté l’EPFL

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Publications associées (40)

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The influence of dye structure on charge recombination in dye-sensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu

Replacing the nonyl groups on the solar cell dye Ru(4,4'-carboxylic acid-2,2'-bipyridine)-( 4,4'-dinonyl-2,2'-bipyridine)(NCS)(2) (Z-907) with amino groups results in a marked decrease in solar cell performance. This is despite the fact that the amino deri ...

2011

Solar reduction of carbon dioxide on copper-tin electrocatalysts with energy conversion efficiency near 20%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu, Dan Ren, Jing Gao, Meng Xia, Jun Li

Solar-driven carbon dioxide reduction has witnessed a renaissance in the past decades, but the system suffers from low reaction rates. Here the authors develop a copper/tin-oxide electrocatalyst, achieving a new benchmark solar-to-CO energy conversion effi ...

Nature Portfolio2022

The Rise of Dye-Sensitized Solar Cells: From Molecular Photovoltaics to Emerging Solid-State Photovoltaic Technologies

Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Marko Stojanovic, Natalie Flores Diaz, Yuhang Liu, Jovana Milic, Yameng Ren, Zhongjin Shen, Lukas Pfeifer

Over the past three decades, dye-sensitized solar cells (i. e. Gratzel cells) have evolved from a pioneering concept of molecular photovoltaics to large-scale industrial deployment. In this review article, we provide a historical overview of the developmen ...

WILEY-V C H VERLAG GMBH2021

Molecular Engineering of Simple Metal-Free Organic Dyes Derived from Triphenylamine for Dye-Sensitized Solar Cell Applications

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Farzan Jazaeri, Yasemin Saygili, Parnian Ferdowsi, Yuhang Liu

Two new metal-free organic sensitizers, L156 and L224, were designed, synthesized, and characterized for application in dye-sensitized solar cells (DSCs). The structures of the dyes contain a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4- ...

WILEY-V C H VERLAG GMBH2020

Cobalt Redox Mediators for Ruthenium-Based Dye-Sensitized Solar Cells: A Combined Impedance Spectroscopy and Near-IR Transmittance Study

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu

Dye-sensitized solar cells with power conversion efficiencies of up to 6.5% have been fabricated using a cobalt trisbipyridyl redox mediator with the cis-diisothiocyanato-(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-dinonyl) ruthenium(II) ( ...

American Chemical Society2011

Flexible perovskite solar cells with simultaneously improved efficiency, operational stability, and mechanical reliability

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu, Felix Thomas Eickemeyer

Although great progress is being made toward improving the power conversion efficiency (PCE) and the operational stability of perovskite solar cells (PSCs), little attention is being paid to their mechanical reliability, which is particularly important for ...

CELL PRESS2021

Guanine‐Stabilized Formamidinium Lead Iodide Perovskites

Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Amita Ummadisingu, Marko Mladenovic, Dominik Józef Kubicki, David Lyndon Emsley, Linfeng Pan, Paramvir Ahlawat, Yuhang Liu, Jovana Milic, Dan Ren, Marco Alejandro Ruiz Preciado

Formamidinium (FA) lead iodide perovskite materials feature promising photovoltaic performances and superior thermal stabilities. However, conversion of the perovskite α‐FAPbI3 phase to the thermodynamically stable yet photovoltaically inactive δ‐FAPbI3 ph ...

2020

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

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

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

Thiocyanate-Mediated Dimensionality Transformation of Low- Dimensional Perovskites for Photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Claudia Esther Avalos, Zaiwei Wang, Yuhang Liu, Brian Irving Carlsen, Jovana Milic, Dan Ren

Two-dimensional (2D) hybrid perovskite solar cells have induced widespread research interest owing to their higher stability as compared to three-dimensional (3D) analogues. The photovoltaic performance, however, is still limited. Here, we report a perovsk ...

2022

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

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

Chemically tailored molecular surface modifiers for efficient and stable perovskite photovoltaics

Michael Graetzel, Ulf Anders Hagfeldt, Yuhang Liu, Bitao Dong

Perovskite solar cells (PSCs) have attracted intense attention based on their high power conversion efficiency and low production cost. However, due to the polycrystalline nature and the intrinsic hydrophilicity of the metal halide perovskite moieties, the ...

WILEY2021

Enabling full-scale grain boundary mitigation in polycrystalline perovskite solids

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Jingshan Luo, Lichen Zhao, Yuhang Liu, Felix Thomas Eickemeyer

There exists a considerable density of interaggregate grain boundaries (GBs) and intra-aggregate GBs in polycrystalline perovskites. Mitigation of intra- aggregate GBs is equally notable to that of interaggregate GBs as intra-aggregate GBs can also cause d ...

AMER ASSOC ADVANCEMENT SCIENCE2022

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

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Marko Mladenovic, Dominik Józef Kubicki, Manuel Cordova, David Lyndon Emsley, Farzaneh Jahanbakhshi, Paramvir Ahlawat, Yuhang Liu, Brian Irving Carlsen, Jovana Milic, Rashmi Runjhun, Aditya Mishra, 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

Modulation of perovskite crystallization processes towards highly efficient and stable perovskite solar cells with MXene quantum dot-modified SnO2

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Yuhang Liu, Tian Chen, Haizhou Lu, Jaeki Jeong

Nanocrystalline tin (iv) oxide (SnO2) electron-transport layers (ETL) have shown great potential for achieving highly efficient, stable perovskite solar cells (PSCs), in particular low-temperature-processed flexible PSCs. Recently, studies have further sho ...

2021

Crystal defects mitigating agents for high power conversion efficiency and stability of perovskite photovoltaic devices

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu

This invention relates to an optoelectronic and/or photovoltaic device comprising acompound used as crystal defect mitigating agent or passivating agent, said compound beingselected from a compound of formula (I),a compound of formula (II),a mixture thereo ...

2019

Revealing fundamentals of charge extraction in photovoltaic devices through potentiostatic photoluminescence imaging

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu

The photocurrent density-voltage (J(V)) curve is the fundamental characteristic to assess opto-electronic devices, in particular solar cells. However, it only yields information on the performance inte-grated over the entire active device area. Here, a met ...

ELSEVIER2022

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

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

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Xiong Li, Wolfgang Richard Tress, David Lyndon Emsley, Paramvir Ahlawat, Claudia Esther Avalos, Zaiwei Wang, Yuhang Liu, Anand Agarwalla, Brian Irving Carlsen, Fan Fu, Aditya Mishra, Haizhou Lu, Felix Thomas Eickemeyer, Xianfu Zhang, Likai Zheng

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

Tailored Amphiphilic Molecular Mitigators for Stable Perovskite Solar Cells with 23.5% Efficiency

Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Mohammad Ibrahim Dar, Xiong Li, Linfeng Pan, Zaiwei Wang, Yuhang Liu, Brian Irving Carlsen, Dan Ren, Marco Alejandro Ruiz Preciado, Bowen Yang, Felix Thomas Eickemeyer, Hongwei Zhu

Passivation of interfacial defects serves as an effective means to realize highly efficient and stable perovskite solar cells (PSCs). However, most molecular modulators currently used to mitigate such defects form poorly conductive aggregates at the perovs ...

Wiley2020

Ultrahydrophobic 3D/2D fluoroarene bilayer-based water-resistant perovskite solar cells with efficiencies exceeding 22%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Mohammad Ibrahim Dar, Neha Arora, Linfeng Pan, Ryusuke Uchida, Yuhang Liu, Jovana Milic, Alexander Roland Uhl, Seckin Akin

Preventing the degradation of metal perovskite solar cells (PSCs) by humid air poses a substantial challenge for their future deployment. We introduce here a two-dimensional (2D) A(2)PbI(4) perovskite layer using pentafluoro-phenylethylammonium (FEA) as a ...

2019