Publications de Yiming Cao | EPFL Graph Search

Hydroxamic acid pre-adsorption raises the efficiency of cosensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Yiming Cao, Felix Thomas Eickemeyer, Yameng Ren, Dan Zhang, Jiajia Suo

Dye-sensitized solar cells (DSCs) convert light into electricity by using photosensitizers adsorbed on the surface of nanocrystalline mesoporous titanium dioxide (TiO2) films along with electrolytes or solid charge-transport materials(1-3). They possess ma ...

NATURE PORTFOLIO2023

A molecular photosensitizer achieves a Voc of 1.24 V enabling highly efficient and stable dye-sensitized solar cells with copper(II/I)-based electrolyte

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Yiming Cao, Marko Stojanovic, Etienne Christophe Socie, Felix Thomas Eickemeyer, Yameng Ren, Dan Zhang

To develop photosensitizers with high open-circuit photovoltage (Voc) is a crucial strategy to enhance the power conversion efficiency (PCE) of co-sensitized solar cells. Here, we show a judiciously tailored organic photosensitizer, coded MS5, featuring th ...

Nature Research2021

A Blue Photosensitizer Realizing Efficient and Stable Green Solar Cells via Color Tuning by the Electrolyte

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Yiming Cao, Peng Wang, Yameng Ren, Dan Zhang

Semitransparent dye-sensitized solar cells (DSCs) are appealing as aesthetically pleasing and colorful see-through photovoltaics. Green semitransparent DSCs have been presented, but the best ones rely on green zinc porphyrin photosensitizers and high volat ...

Wiley-V C H Verlag Gmbh2020

Blue Photosensitizer with Copper(II/I) Redox Mediator for Efficient and Stable Dye‐Sensitized Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Ulf Anders Hagfeldt, Yiming Cao, Natalie Flores Diaz, George Cameron Fish, Yameng Ren, Dan Zhang

Dye-sensitized solar cells (DSCs) based on copper(II/I) redox mediators have recently achieved notable performance progress through tailoring the ligand structure of the copper complexes, exploiting cosensitization, and introducing an advanced device struc ...

2020

Experimental Generation and Time Multiplexing of Data-Carrying Nyquist Sinc Shaped Channels from a Single Microresonator-based Kerr Frequency Comb

Tobias Kippenberg, Martin Hubert Peter Pfeiffer, Yiming Cao, Fatemeh Alishahi, Arne Kordts, Maxim Karpov, Ahmad Fallahpour

We experimentally achieve optical time multiplexing of multiple Nyquist channels. A single microresonator Kerr comb allows the generation of multiple Nyquist sinc shaped pulse trains. TDM of pulse trains are obtained through wavelength conversion inside a ...

IEEE2019

Demonstration of Tunable and Reconfigurable Optical Nyquist Channel Aggregation of QPSK-to-16QAM and BPSK-to-4PAM Using Nonlinear Wave Mixing and a Kerr Frequency Comb

Tobias Kippenberg, Martin Hubert Peter Pfeiffer, Yiming Cao, Fatemeh Alishahi, Arne Kordts, Maxim Karpov, Ahmad Fallahpour

A tunable and reconfigurable optical Nyquist channels aggregation is experimentally demonstrated. The proposed method two aggregate lower order modulation formats into a single higher order one. Two 16 Gbaud QPSK Nyquist pulses aggregated to a 16 QAM Nyqui ...

IEEE2019

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

Redox melts formed by copper (i)/(ii) complexes as charge transfer and charge storage materials

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Yiming Cao, Marko Stojanovic, Marina Freitag

The present invention relates to a redox copper complex melt comprising a metalorganic complex of formula (I) [Cu (La) n ] (I), wherein n is an integer 2; and La is a bidentate ligand selected from a ligand according to any one of formulae (1) and (2): ...

2018

Stable and Efficient Organic Dye-Sensitized Solar Cell Based on Ionic Liquid Electrolyte

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Yiming Cao, Lin Yang, Peng Wang, Jing Zhang

Dye-sensitized solar cells (DSCs) for outdoor applications must show both high efficiency and long-term stability. Here we introduce a co-sensitized, ionic liquid electrolyte-based DSC meeting these requirements. A key feature of our embodiment is the conc ...

CELL PRESS2018

A Stable Blue Photosensitizer for Color Palette of Dye-Sensitized Solar Cells Reaching 12.6% Efficiency

Shaik Mohammed Zakeeruddin, Hoi Nok Tsao, Yiming Cao

2018

Direct Contact of Selective Charge Extraction Layers Enables High-Efficiency Molecular Photovoltaics

Shaik Mohammed Zakeeruddin, Yiming Cao, Yuhang Liu

2018

Influence of redox electrolyte on the device performance of phenothiazine based dye sensitized solar cells

Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Yiming Cao

2018

Electron-Affinity-Triggered Variations on the Optical and Electrical Properties of Dye Molecules Enabling Highly Efficient Dye-Sensitized Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Péter Kalman Péchy, Ulf Anders Hagfeldt, Yiming Cao, Marko Stojanovic, Mohammad Ibrahim Dar, Yasemin Saygili, Weiwei Zhang, Yuhang Liu

The synthesis, characterization, and photovoltaic performance of a series of indacenodithiophene (IDT)-based D--A organic dyes with varying electron-accepting units is presented. By control of the electron affinity, perfectly matching energy levels were ac ...

Wiley-VCH Verlag GmbH2018

11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials

Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Joël Teuscher, Ulf Anders Hagfeldt, Norman Pellet, Yiming Cao, Amita Ummadisingu, Fabrizio Giordano, Jingshan Luo, Yasemin Saygili, Marina Freitag

Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we rep ...

Nature Publishing Group2017

High Absorption Coefficient Cyclopentadithiophene Donor-Free Dyes for Liquid and Solid-State Dye-Sensitized Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yelin Hu, Yiming Cao, Antonio Abate

We report a series of "donor-free" dyes featuring moieties of oligo(4,4-dihexyl-4H-cyclopenta[1,2-b:5,4-b']dithiophene) (CPDT) functionalized with cyanoacrylic end groups for mesoscopic titania solar cells based on I-/I-3(-) or Co(II)/Co(III) redox couple ...

Amer Chemical Soc2016

Copper Bipyridyl Redox Mediators for Dye-Sensitized Solar Cells with High Photovoltage

Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ladislav Kavan, Ulf Anders Hagfeldt, Norman Pellet, Yiming Cao, Fabrizio Giordano, Yasemin Saygili, Marina Freitag, Magnus Söderberg

Redox mediators play a major role determining the photocurrent and the photovoltage in dye-sensitized solar cells (DSCs). To maintain the photocurrent, the reduction of oxidized dye by the redox mediator should be significantly faster than the electron bac ...

American Chemical Society2016

MicroRNA-206 functions as a pleiotropic modulator of cell proliferation, invasion and lymphangiogenesis in pancreatic adenocarcinoma by targeting ANXA2 and KRAS genes

Yiming Cao

Recent advances in cancer biology have emerged important roles for microRNAs (miRNAs) in regulating tumor responses. However, their function in mediating intercellular communication within the tumor microenvironment is thus far poorly explored. Here, we fo ...

Nature Publishing Group2015

Eutectic melts

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yiming Cao, Peng Wang

The present invention refers to using the principal of a room temperature molten ionic liquid, to an electrolyte, to devices comprising the ionic liquid co-melting, and to the preparation of a room temperature ionic liquid via various physical and chemical ...

2009

Dye-sensitized solar cells with solvent-free ionic liquid electrolytes

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yu Bai, Yiming Cao, Peng Wang

We systematically studied the temperature-dependent physicochemical properties, such as density, conductivity, and fluidity, of 1,3-dialkylimidazolium iodides. In combination with the amphiphilic Z907Na sensitizer, we have found that it is important to use ...

2008

Tetrahydrothiophenium-based ionic liquids for high efficiency dye-sensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mingkui Wang, Yiming Cao, Peng Wang

Binary melts of S-ethyltetrahydrothiophenium iodide and dicyanoamide (or tricyanomethide) have been employed for dye-sensitized solar cells with high power conversion efficiencies up to 6.9% under the illumination of AM 1.5G full sunlight. We have further ...

2008