Publications de Jiahuan Zhang | EPFL Graph Search

Intermediate phase engineering of halide perovskites for photovoltaics

Ulf Anders Hagfeldt, Zaiwei Wang, Wanchun Xiang, Jiahuan Zhang

Metal halide perovskites serving as one of the most promising photovoltaic materials are gaining considerable attention worldwide. For achieving high performance as well as long-term stability of the perovskite solar cells (PSCs), a good quality of perovsk ...

CELL PRESS2022

Formation and Stabilization of Inorganic Halide Perovskites for Photovoltaics

Ulf Anders Hagfeldt, Zaiwei Wang, Wanchun Xiang, Jiahuan Zhang

In the last decade, halide perovskites have emerged as new semiconductors that revolutionize the photovoltaic field. Among this family of materials, all-inorganic halide perovskites are becoming a research paradigm because of their outstanding photophysica ...

ELSEVIER2021

Intermediate Phase Enhances Inorganic Perovskite and Metal Oxide Interface for Efficient Photovoltaics

Michael Graetzel, Ulf Anders Hagfeldt, Dominik Józef Kubicki, Wolfgang Richard Tress, David Lyndon Emsley, Claudia Esther Avalos, Zaiwei Wang, Yuhang Liu, Anand Agarwalla, Brian Irving Carlsen, Wanchun Xiang, Mona Shasti, Jiahuan Zhang, Aditya Mishra, Haizhou Lu, Ziyun Wang

Interfacial modification is crucial to fully develop the potential of semiconductor devices, including the revolutionary halide perovskite-based optoelectronics, such as photovoltaics, light-emitting diodes, and photodetectors. The all-inorganic halide per ...

CELL PRESS2020

Stabilization of Highly Efficient and Stable Phase-Pure FAPbI(3)Perovskite Solar Cells by Molecularly Tailored 2D-Overlayers

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Mohammad Ibrahim Dar, Jiyoun Seo, Yuhang Liu, Seckin Akin, Jiahuan Zhang, Felix Thomas Eickemeyer, Hong Zhang, Hongwei Zhu

As a result of their attractive optoelectronic properties, metal halide APbI(3)perovskites employing formamidinium (FA(+)) as the A cation are the focus of research. The superior chemical and thermal stability of FA(+)cations makes alpha-FAPbI(3)more suita ...

Wiley-VCH Verlag GmbH2020

Ba-induced phase segregation and band gap reduction in mixed-halide inorganic perovskite solar cells

Michael Graetzel, Ulf Anders Hagfeldt, Dominik Józef Kubicki, Wolfgang Richard Tress, Jingshan Luo, David Lyndon Emsley, Albert Hofstetter, Xiaoyan Wang, Zaiwei Wang, Wanchun Xiang, Jiahuan Zhang, Xiaoyu Wang

All-inorganic metal halide perovskites are showing promising development towards efficient long-term stable materials and solar cells. Element doping, especially on the lead site, has been proved to be a useful strategy to obtain the desired film quality a ...

Nature Research2019

Electrochemically polymerized poly (3, 4-phenylenedioxythiophene) as efficient and transparent counter electrode for dye sensitized solar cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Lin Yang, Jiahuan Zhang, Yan Hao

A new conducting polymer poly (3, 4-phenylenedioxythiophene) is synthesized by the electrochemical polymerization technique with different solvents. We find that solvents used in electrochemical polymerization play important roles for the catalytic activit ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Agonists and Antagonists of Protease-Activated Receptor 2 Discovered within a DNA-Encoded Chemical Library Using Mutational Stabilization of the Target

Ye Zhang, Sevan Mleh Habeshian, Jiahuan Zhang

2018

Design rules for minimizing voltage losses in high-efficiency organic solar cells

Wolfgang Richard Tress, Jiahuan Zhang

2018

Enhanced longevity and metabolism by brown adipose tissue with disruption of the regulator of G protein signaling 14

Elena Katsyuba, Johan Auwerx, Jiahuan Zhang

2018

New covalently bonded dye/hole transporting material for better charge transfer in solid-state dye-sensitized solar cells

Nikolaos Vlachopoulos, Jiahuan Zhang

2018

The Importance of Pendant Groups on Triphenylamine-Based Hole Transport Materials for Obtaining Perovskite Solar Cells with over 20% Efficiency

Nikolaos Vlachopoulos, Liang Wang, Lin Yang, Peng Liu, Weiwei Zhang, Jiahuan Zhang

2018

Tailor-Making Low-Cost Spiro[fluorene-9,9 '-xanthene]-Based 3D Oligomers for Perovskite Solar Cells

Ulf Anders Hagfeldt, Liang Wang, Peng Liu, Jiahuan Zhang

The power-conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have increased rapidly from about 4% to 22% during the past few years. One of the major challenges for further improvement of the efficiency of PSCs is the lack of sufficiently good ...

Cell Press2017

Incorporation of Counter Ions in Organic Molecules: New Strategy in Developing Dopant-Free Hole Transport Materials for Efficient Mixed-Ion Perovskite Solar Cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Liang Wang, Lin Yang, Monica Marcela Lira Cantu, Jiahuan Zhang

Hole transport matertial (HTM) as charge selective layer in perovskite solar cells (PSCs) plays an important role in achieving high power conversion efficiency (PCE). It is known that the dopants and additives are necessary in the HTM in order to improve t ...

Wiley-V C H Verlag Gmbh2017

Strategy to Boost the Efficiency of Mixed-Ion Perovskite Solar Cells: Changing Geometry of the Hole Transporting Material

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Jiahuan Zhang

The hole transporting material (HTM) is an essential component in perovskite solar cells (PSCs) for efficient extraction and collection of the photoinduced charges. Triphenylamine- and carbazole-based derivatives have extensively been explored as alternati ...

Amer Chemical Soc2016

The effect of mesoporous TiO2 pore size on the performance of solid-state dye sensitized solar cells based on photoelectrochemically polymerized Poly(3,4-ethylenedioxythiophene) hole conductor

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Jiahuan Zhang

Photoelectrochemical polymerization of poly(3,4-ethylenedioxythiphene) (PEDOT) has recently been introduced and widely investigated for fabrication of the hole transporting material (HTM) in highly efficient solid state dye sensitized solar cells (sDSCs). ...

Pergamon-Elsevier Science Ltd2016

Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Yasemin Saygili, Kazuteru Nonomura, Enrico Polanski, Anna Eriksson, Jiahuan Zhang, Yan Hao

Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D-pi-A dye (Dyenamo Blue), based on the diketopyrro ...

2016

Efficient solid-state dye sensitized solar cells: The influence of dye molecular structures for the in-situ photoelectrochemically polymerized PEDOT as hole transporting material

Mohammad Khaja Nazeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Jiahuan Zhang

Solid-state dye sensitized solar cells (sDSCs) with organic small molecule hole transporting materials (HTMs) have limited efficiencies due to the incomplete pore filling of the HTMs in the thick mesoporous electrodes and the low hole conductivity of HTMs. ...

Elsevier Science Bv2016

Ambient air-processed mixed-ion perovskites for high-efficiency solar cells

Ulf Anders Hagfeldt, Juan-Pablo Correa-Baena, Jiahuan Zhang

Mixed-ion (FAPbI(3))(1-x)(MAPbBr(3))(x) perovskite solar cells have achieved power conversion efficiencies surpassing 20%. However, in order to obtain these high efficiencies the preparation is performed in a controlled inert atmosphere. Here, we report a ...

Royal Society of Chemistry2016

Efficient Blue-Colored Solid-State Dye-Sensitized Solar Cells: Enhanced Charge Collection by Using an in Situ Photoelectrochemically Generated Conducting Polymer Hole Conductor

Michael Graetzel, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Thomas Wesley Holcombe, Jiahuan Zhang, Yan Hao

A high power conversion efficiency (PCE) of 5.5% was achieved by efficiently incorporating a diketopyrrolopyrrole-based dye with a conducting polymer poly(3,4-ethylenediothiophene) (PEDOT) hole-transporting material (HTM) that was formed in situ, compared ...

Wiley-V C H Verlag Gmbh2016

Electron trapping mechanisms in magnetron injection guns

Jean-Philippe Hogge, Ioannis Pagonakis, Konstantinos Avramidis, Jiahuan Zhang

A key parameter for the gyrotron operation and efficiency is the presence of trapped electrons. Two electron trapping mechanisms can take place in gyrotrons: (i) the adiabatic trap and (ii) the magnetic potential well. Their influence on the gyrotron opera ...

American Institute of Physics (AIP)2016