Publications by Chenyi Yi | EPFL Graph Search

Double Layer Composite Electrode Strategy for Efficient Perovskite Solar Cells with Excellent Reverse-Bias Stability (vol 15, 12, 2022)

Michael Graetzel, Chenyi Yi, Wolfgang Richard Tress

2023

Ligand-Modulated Excess PbI2 Nanosheets for Highly Efficient and Stable Perovskite Solar Cells

Ulf Anders Hagfeldt, Chenyi Yi, Yi Ding, Jingshan Luo, Xiaoyu Zhang, Zaiwei Wang, Zhen Yang

Excess lead iodide (PbI2), as a defect passivation material in perovskite films, contributes to the longer carrier lifetime and reduced halide vacancies for high-efficiency perovskite solar cells. However, the random distribution of excess PbI2 also leads ...

Wiley-V C H Verlag Gmbh2020

Photovoltaic Performance of Porphyrin-Based Dye-Sensitized Solar Cells with Binary Ionic Liquid Electrolytes

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Chenyi Yi, Pankaj Kumar Yadav

Herein, green porphyrin sensitizer Y350-based dye-sensitized solar cells (DSCs) with binary ionic liquid-based electrolytes are studied, which are a mixture of 1-methyl-3-propyl-imidazolium iodide and 1-methyl-1-butylpyrrolidinium bis(trifluromethylsulfony ...

2020

Comprehensive control of voltage loss enables 11.7% efficient solid-state dye-sensitized solar cells

Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Ladislav Kavan, Ulf Anders Hagfeldt, Chenyi Yi, Yiming Cao, Jingshan Luo, Yasemin Saygili, Heewon Bahng, Weiwei Zhang, Yuhang Liu, Yinghui Wu

The relatively large voltage loss (Vloss) in excitonic type solar cells severely limits their power conversion efficiencies (PCEs). Here, we report a comprehensive control of Vloss through efficacious engineering of the sensitizer and redox mediator, makin ...

2018

Dopant-free star-shaped hole-transport materials for efficient and stable perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi, Xiong Li, Dongqin Bi, Fei Zhang, Shilong Wang

Two star-shaped TPA-based small-molecule materials (Z1012 and Z1013) were designed and synthesized in this paper. These molecules show high hole mobility and suitable energy levels for CH3NH3PbI3-based perovskite solar cells. Photovoltaic cells based on th ...

Elsevier2017

Atomically Altered Hematite for Highly Efficient Perovskite Tandem Water-Splitting Devices

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi, Nripan Mathews

Photoelectrochemical (PEC) cells are attractive for storing solar energy in chemical bonds through cleaving of water into oxygen and hydrogen. Although hematite (alpha-Fe2O3) is a promising photoanode material owing to its chemical stability, suitable band ...

Wiley-VCH Verlag Berlin2017

Over 20% PCE perovskite solar cells with superior stability achieved by novel and low-cost hole-transporting materials

Michael Graetzel, Shaik Mohammed Zakeeruddin, Norman Pellet, Chenyi Yi, Xiong Li, Jingshan Luo, Dongqin Bi, Fei Zhang, Hongwei Zhu, Shilong Wang, Ziyun Wang

The exploration of alternative low-cost molecular hole-transporting materials (HTMs) for both highly efficient and stable perovskite solar cells (PSCs) is a relatively new research area. Two novel HTMs using the thiophene core were designed and synthesized ...

Elsevier Science Bv2017

Isomer-Pure Bis-PCBM-Assisted Crystal Engineering of Perovskite Solar Cells Showing Excellent Efficiency and Stability

Michael Graetzel, Shaik Mohammed Zakeeruddin, Norman Pellet, Chenyi Yi, Xiong Li, Jingshan Luo, Dongqin Bi, Fei Zhang, Shilong Wang

A fullerene derivative (alpha-bis-PCBM) is purified from an as-produced bis-phenyl-C-61-butyric acid methyl ester (bis-[60]PCBM) isomer mixture by preparative peak-recycling, high-performance liquid chromatography, and is employed as a templating agent for ...

Wiley-Blackwell2017

High efficiency large area perovskite solar cells and process for producing the same

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Chenyi Yi, Xiong Li, Dongqin Bi

The present invention relates to a method for producing a solid state solar cell, comprising the steps of providing a conductive support layer or current collector, applying a metal oxide layer on the conducting support layer, applying at least one sensiti ...

2017

Entropic stabilization of mixed A-cation ABX3 metal halide perovskites for high performance perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Negar Ashari Astani, Chenyi Yi, Simone Meloni, Jingshan Luo, Ariadni Boziki

ABX(3)-type organic lead halide perovskites currently attract broad attention as light harvesters for solar cells due to their high power conversion efficiency (PCE). Mixtures of formamidinium (FA) with methylammonium (MA) as A-cations show currently the b ...

2016

A Novel Dopant-Free Triphenylamine Based Molecular "Butterfly" Hole-Transport Material for Highly Efficient and Stable Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi, Gwénolé Jean Jacopin, Xiong Li, Jingshan Luo, Fei Zhang, Shilong Wang

Wiley-V C H Verlag Gmbh2016

Dopant-Free Donor (D)–p–D–p–D Conjugated Hole- Transport Materials for Efficient and Stable Perovskite Solar Cells

Shaik Mohammed Zakeeruddin, Chenyi Yi, Xiong Li, Jingshan Luo, Dongqin Bi, Fei Zhang, Shilong Wang

Three novel hole-transporting materials (HTMs) using the 4-methoxytriphenylamine (MeOTPA) core were designed and synthesized. The energy levels of the HTMs were tuned to match the perovskite energy levels by introducing symmetrical electron-donating groups ...

2016

Polymer-templated nucleation and crystal growth of perovskite films for solar cells with efficiency greater than 21%

Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Ulf Anders Hagfeldt, Chenyi Yi, Xiong Li, Jingshan Luo, Dongqin Bi, Fei Zhang

The past several years have witnessed the rapid emergence of a class of solar cells based on mixed organic-inorganic halide perovskites. Today's state-of-the-art perovskite solar cells (PSCs) employ various methods to enhance nucleation and improve the smo ...

Nature Publishing Group2016

A novel one-step synthesized and dopant-free hole transport material for efficient and stable perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi, Xiong Li, Jingshan Luo, Dongqin Bi, Fei Zhang, Shilong Wang

A hole transport material ST1 was synthesized by a one-step Heck reaction. Compared to Spiro-OMeTAD, perovskite solar cells with ST1 exhibit a remarkable overall power conversion efficiency of 15.4% without the use of any dopants and additives, which is co ...

Royal Society of Chemistry2016

Identifying Fundamental Limitations in Halide Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi, Nripan Mathews

The temperature dependence of the principal photovoltaic parameters of perovskite photovoltaics is studied. The recombination activation energy is in good agreement with the perovskite's bandgap energy, thereby placing an upper bound on the open-circuit vo ...

Wiley-Blackwell2016

Porphyrin based sensitizer for dye-sensitized solar cell

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi, Fabrizio Giordano

The present invention relates to compounds of formula (I) based on a porphyrin core and a π-conjugated linker or acceptor introduced between the porphyrin core and an anchoring group having a high absorption coefficient covering the whole UV-Visible and ne ...

2016

Perovskite Photovoltaics with Outstanding Performance Produced by Chemical Conversion of Bilayer Mesostructured Lead Halide/TiO2 Films

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi, Xiong Li, Jingshan Luo

Wiley-Blackwell2016

A vacuum flash-assisted solution process for high-efficiency large-area perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Ulf Anders Hagfeldt, Chenyi Yi, Xiong Li, Jingshan Luo, Dongqin Bi

Metal halide perovskite solar cells (PSCs) currently attract enormous research interest because of their high solar-to-electric power conversion efficiency (PCE) and low fabrication costs, but their practical development is hampered by difficulties in achi ...

American Association for the Advancement of Science2016

Molecular Engineering of Potent Sensitizers for Very Efficient Light Harvesting in Thin-Film Solid-State Dye-Sensitized Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Marcel Roland Schreier, Norman Pellet, Chenyi Yi, Yelin Hu, Fabrizio Giordano, Xiaoyu Zhang, Yi Xu

Dye-sensitized solar cells (DSSCs) have shown significant potential for indoor arid building integrated photovoltaic applications. Herein we present three new D-A-pi-A organic sensitizers, XY1, XY2, and XY3, that exhibit high molar extinction coefficients ...

Amer Chemical Soc2016

A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

Michael Graetzel, Chenyi Yi

Two new photosensitizers featured with a cyanoacrylic acid electron acceptor (A) and a hybrid electron donor (D) of cyclopentadithiophene and dithiafulvenyl, either directly linked or separated by a phenyl ring, were synthesized and characterized. Both of ...

Beilstein-Institut2015