Publications de Yuhang Liu | EPFL Graph Search

Upgrading Spiro-OMeTAD with β-Chloroethylcarbazole to Improve the Stability of Perovskite Solar Cells

Michael Graetzel, Yuhang Liu, Haizhou Lu, Jialin Wang

Spiro-OMeTAD has served as a crucial hole transporting material (HTM) in the advancement of efficient perovskite solar cells (PSCs). However, the diminished thermal stability of lithium-doped Spiro-OMeTAD (Li-Spiro) has been a limiting factor, leading to a ...

AMER CHEMICAL SOC2024

Radical polymeric p-doping and grain modulation for stable, efficient perovskite solar modules

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu, Brian Irving Carlsen, Felix Thomas Eickemeyer

High-quality perovskite light harvesters and robust organic hole extraction layers are essential for achieving high-performing perovskite solar cells (PSCs). We introduce a phosphonic acid???functionalized fullerene derivative in mixed-cation perovskites a ...

American Association for the Advancement of Science2023

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

Michael Graetzel, Shaik Mohammed Zakeeruddin, Dmitry Bogachuk, 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

Conformal quantum dot-SnO2 layers as electron transporters for efficient perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu, Haizhou Lu, Felix Thomas Eickemeyer, Jaeki Jeong

Improvements to perovskite solar cells (PSCs) have focused on increasing their power conversion efficiency (PCE) and operational stability and maintaining high performance upon scale-up to module sizes. We report that replacing the commonly used mesoporous ...

American Association for the Advancement of Science2022

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

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

Hole transport material, synthesis thereof, and solar cell

Michael Graetzel, Shaik Mohammed Zakeeruddin, Michael Bauer, Yuhang Liu

The organic small molecule 4,4',4",4"'-(5,5-dimethoxycyclopenta-1,3-diene-1,2,3,4-tetrayl)tetrakis(N,N-bis(4-methoxyhenyl)aniline (CPDA 1), shows electrochemical properties very close to spiro-OMeTAD indicating a high compatibility with PSC systems for its ...

2022

Interface modification to achieve high-efficiency and stable perovskite solar cells

Linfeng Pan, Yuhang Liu, Hongwei Zhu, Zhongjin Shen

The organic-inorganic hybrid perovskite solar cells (PSCs) achieve relatively high power conversion efficiencies (PCEs) over the past few years. However, defects on the surface and at the grain boundaries of the perovskite active layers are critical factor ...

ELSEVIER SCIENCE SA2022

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

Efficient and Stable Large Bandgap MAPbBr(3) Perovskite Solar Cell Attaining an Open Circuit Voltage of 1.65 V

Michael Graetzel, Shaik Mohammed Zakeeruddin, Thomas Paul Baumeler, David Lyndon Emsley, Linfeng Pan, Anwar Qasem M Alanazi, Yuhang Liu, Jing Gao, Felix Thomas Eickemeyer, Hongwei Zhu, Michael Allan Hope, Olivier Ouellette

We report on the preparation of MAPbBr(3) perovskite films of high electronic quality by applying a methylamine (MA) vapor treatment and mitigating surface defects using the amphiphilic molecular passivator, neopentylammonium chloride (NPACl). We find that ...

2022

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

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu, Felix Thomas Eickemeyer, Chen Jiang, Min Chen

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

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

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

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, Loï Charles Carbone, Yuhang Liu, Brian Irving Carlsen, Jovana Milic, Rashmi Runjhun, Aditya Mishra, Toru Nakamura, Michael Allan Hope, Thomas Schneeberger

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

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

Cyclopentadiene-Based Hole-Transport Material for Cost-Reduced Stabilized Perovskite Solar Cells with Power Conversion Efficiencies Over 23%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Thomas Paul Baumeler, Michael Bauer, Yuhang Liu, Felix Thomas Eickemeyer, Hongwei Zhu

Hole transport materials (HTM) are an important component in perovskite solar cells (PSC). Despite a multitude of HTMs developed in recent years, only few of them lead to solar cells with efficiencies over 20%. Therefore, it is still a challenge to develop ...

2021

Synergistic Effect of Fluorinated Passivator and Hole Transport Dopant Enables Stable Perovskite Solar Cells with an Efficiency Near 24%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Linfeng Pan, Yuhang Liu, Felix Thomas Eickemeyer, Yameng Ren, Hongwei Zhu, Olivier Ouellette

Long-term durability is critically important for the commercialization of perovskite solar cells (PSCs). The ionic character of the perovskite and the hydrophilicity of commonly used additives for the hole-transporting layer (HTL), such as lithium bis(trif ...

2021

Combined Precursor Engineering and Grain Anchoring Leading to MA-Free, Phase-Pure, and Stable alpha-Formamidinium Lead Iodide Perovskites for Efficient Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Carole Graetzel, Linfeng Pan, Yuhang Liu, Dan Ren, Jing Gao, Hongwei Zhu, Anurag Krishna, Olivier Ouellette

alpha-Formamidinium lead iodide (alpha-FAPbI(3)) is one of the most promising candidate materials for high-efficiency and thermally stable perovskite solar cells (PSCs) owing to its outstanding optoelectrical properties and high thermal stability. However, ...

Wiley-VCH Verlag GmbH2021

Organic Ammonium Halide Modulators as Effective Strategy for Enhanced Perovskite Photovoltaic Performance

Michael Graetzel, Ulf Anders Hagfeldt, Yuhang Liu, Bitao Dong, Seckin Akin, Lukas Pfeifer

Despite rapid improvements in efficiency, long-term stability remains a challenge limiting the future up-scaling of perovskite solar cells (PSCs). Although several approaches have been developed to improve the stability of PSCs, applying ammonium passivati ...

WILEY2021

Low-Cost Dopant Additive-Free Hole-Transporting Material for a Robust Perovskite Solar Cell with Efficiency Exceeding 21%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Linfeng Pan, Yuhang Liu, Felix Thomas Eickemeyer, Yameng Ren, Hongwei Zhu, Zhongjin Shen

Developing hole-transporting materials (HTMs) with appropriate molecular configuration and charge mobility is important to improve perovskite solar cell (PSC) photovoltaic performance and their feasibility for commercialization. In this work, a novel pyram ...

2021