Ulf Anders Hagfeldt

Cette personne n’est plus à l’EPFL

Publications associées (575)

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Publications associées (575)

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Fine-Tuning by Triple Bond of Carbazole Derivative Dyes to Obtain High Efficiency for Dye-Sensitized Solar Cells with Copper Electrolyte

Ulf Anders Hagfeldt, Li Zhang

Three novel dyes consisting of a 5,8,15-tris(2-ethylhexyl)-8,15-dihydro-SH-benzo[1,2-b:3,4-b':6,5-b '']tricarbazole (BTC) electron-donating group and a 4,7-bis(4-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (BTBT) pi-bridge with an anchoring group of phen ...

AMER CHEMICAL SOC2020

Cu2O photocathodes with band-tail states assisted hole transport for standalone solar water splitting

Michael Graetzel, Kevin Sivula, Yuhang Liu, Ulf Anders Hagfeldt, Liang Yao, Dan Ren, Linfeng Pan

Photoelectrochemical water splitting provides a promising solution for harvesting and storing solar energy. As the best-performing oxide photocathode, the Cu2O photocathode holds the performance rivaling that of many photovoltaic semiconductor-based photoc ...

2020

Revealing the Mechanism of Doping of spiro-MeOTAD via Zn Complexation in the Absence of Oxygen and Light

Ulf Anders Hagfeldt, Yasemin Saygili, Hui-Seon Kim, Bowen Yang, Jiajia Suo

In this study, a new mechanism for doping of spiro-MeOTAD by Zn(TFSI)(2) is revealed, which is completely different from the mechanism induced by LiTFSI. The oxidation of spiro-MeOTAD is facilitated by complexation between the zinc cation and tert-butylpyr ...

AMER CHEMICAL SOC2020

D35-TiO2 nano-crystalline film as a high performance visible-light photocatalyst towards the degradation of bis-phenol A

Ulf Anders Hagfeldt, Lin Yang, Xue Bai

Dye-sensitized photocatalytic suspension system for wastewater treatment is still limited in practice due to particle aggregation, fast charge carrier recombination, poor stability and recycling issue. In this study, we combine TiO2 nano-crystalline film w ...

ELSEVIER SCIENCE SA2019

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Two new dyes based on a dinuclear rhenium complex and (E)-3-(5-(4-(bis(2,4-dibutoxy-[1,1-biphenyl]-4-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid (namely D35) have been investigated as sensitizers for dye sensitized solar cells (DSSCs). Two different ...

ROYAL SOC CHEMISTRY2019

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Natural systems have marvelously utilized copper complexes featuring sulfur-coordinating ligands, known as blue copper proteins, as efficient electron-transfer mediators in biological processes. Copper complexes with sulfur-coordinating ligands have been a ...

ROYAL SOC CHEMISTRY2019

A Scalable Methylamine Gas Healing Strategy for High-Efficiency Inorganic Perovskite Solar Cells

Ulf Anders Hagfeldt, Zaiwei Wang, Zhipeng Li, Yuqing Wang

An easy and scalable methylamine (MA) gas healing method was realized for inorganic cesium-based perovskite (CsPbX3) layers by incorporating a certain amount of MAX (X=I or Br) initiators into the raw film. It was found that the excess MAX accelerated the ...

WILEY-V C H VERLAG GMBH2019

A hybrid niobium-based oxide with bio-based porous carbon as an efficient electrocatalyst in photovoltaics: a general strategy for understanding the catalytic mechanism

Ulf Anders Hagfeldt, Sining Yun, Cheng Wang, Yixin Zhang, Ziqi Wang

Developing a high-performance catalyst and establishing a catalytic mechanism for understanding the catalytic activity are crucial to new generation photovoltaic technology. In this work, we present a feasible and general route to synthesize a bio-based po ...

ROYAL SOC CHEMISTRY2019

Electronic Structures and Catalytic Activities of Niobium Oxides as Electrocatalysts in Liquid-Junction Photovoltaic Devices

Ulf Anders Hagfeldt, Sheng Meng, Sining Yun, Hang Liu

Two types of nanosized niobium oxides and their composites, pseudohexagonal Nb2O5 (TT-Nb2O5), monoclinic NbO2 (M-NbO2), and the coexistence of TT-Nb2O5 and M-NbO2 (TT-Nb2O5/M-NbO2), are successfully synthesized through the urea-metal chloride route, and th ...

WILEY-V C H VERLAG GMBH2019

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So-called negative capacitance seems to remain an obscure feature in the analysis of the frequency-dependent impedance of perovskite solar cells. It belongs to one of the puzzling peculiarities arising from the mixed ionic-electronic conductivity of this c ...

Springer2019