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Ulf Anders Hagfeldt

Cette personne n’est plus à l’EPFL

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Publications associées (296)

A molecularly engineered hole-transporting material for efficient perovskite solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Ulf Anders Hagfeldt, Peng Gao, Sadig Aghazada, Juan-Pablo Correa-Baena, Antonio Abate, Taisuke Matsui, Michael Saliba, Filippo de Angelis

Soln.-processable perovskite solar cells have recently achieved certified power conversion efficiencies of over 20%, challenging the long-standing perception that high efficiencies must come at high costs. One major bottleneck for increasing the efficie ...

Nature Publishing Group2016

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

Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiency

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Konrad Domanski, Wolfgang Richard Tress, Juan-Pablo Correa-Baena, Antonio Abate, Jiyoun Seo, Taisuke Matsui, Michael Saliba

Today's best perovskite solar cells use a mixture of formamidinium and methylammonium as the monovalent cations. With the addition of inorganic cesium, the resulting triple cation perovskite compositions are thermally more stable, contain less phase impuri ...

Royal Society of Chemistry2016

Unbroken Perovskite: Interplay of Morphology, Electro-optical Properties, and Ionic Movement

Michael Graetzel, Ulf Anders Hagfeldt, Konrad Domanski, Wolfgang Richard Tress, Juan-Pablo Correa-Baena, Antonio Abate, Taisuke Matsui, Michael Saliba, Tor Jesper Jacobsson

Hybrid organic-inorganic perovskite materials have risen up as leading components for light-harvesting applications. However, to date many questions are still open concerning the operation of perovskite solar cells (PSCs). A systematic analysis of the inte ...

Wiley-V C H Verlag Gmbh2016

Monolithic perovskite/silicon-heterojunction tandem solar cells processed at low temperature

Michael Graetzel, Mohammad Khaja Nazeeruddin, Ulf Anders Hagfeldt, Ludmilla Steier, Juan-Pablo Correa-Baena, Antonio Abate, Michael Saliba

Tandem solar cells combining silicon and perovskite absorbers have the potential to outperform state-of-the-art high efficiency silicon single junction devices. However, the practical fabrication of monolithic silicon/perovskite tandem solar cells is chall ...

Royal Soc Chemistry2016

Highly efficient dye-sensitized solar cells achieved through using Pt-free Nb2O5/C composite counter electrode and iodide-free redox couples

Ulf Anders Hagfeldt, Weiwei Zhang, Wenyan Li

To improve the catalytic activity of Nb2O5, a composite Nb2O5/C (Nb2O5 imbedded in carbon support) is synthesized with a simple in situ method and then introduced the composite into dye-sensitized solar cells (DSCs) as a counter electrode (CE) catalyst. Ba ...

Elsevier Science Bv2016

Carbon nanotube-based hybrid hole-transporting material and selective contact for high efficiency perovskite solar cells

Michael Graetzel, Ulf Anders Hagfeldt, Juan-Pablo Correa-Baena, Antonio Abate

We demonstrate a high efficiency perovskite solar cell with a hybrid hole-transporting material-counter electrode based on a thin single-walled carbon nanotube (SWCNT) film and a drop-cast 2,2,7,-7-tetrakis(N, N-di-p-methoxyphenylamine)-9,90-spirobifluoren ...

Royal Soc Chemistry2016

'Low-cost Cr doped Pt3Ni alloy supported on carbon nanofibers composites counter electrode for efficient dye-sensitized solar cells' (vol 328, pg 543, 2016)

Ulf Anders Hagfeldt, Weiwei Zhang, Mei Wang

Elsevier2016

Bipolar Membrane-Assisted Solar Water Splitting in Optimal pH

Michael Graetzel, Ulf Anders Hagfeldt, Jingshan Luo, Dongqin Bi

Wiley-V C H Verlag Gmbh2016

Highly Efficient and Stable Perovskite Solar Cells based on a Low-Cost Carbon Cloth

Michael Graetzel, Ulf Anders Hagfeldt, Ludmilla Steier, Konrad Domanski, Fabrizio Giordano, Wolfgang Richard Tress, Juan-Pablo Correa-Baena, Antonio Abate, Taisuke Matsui, Michael Saliba

Wiley-VCH Verlag Berlin2016

Factors Affecting the Performance of Champion Silyl-Anchor Carbazole Dye Revealed in the Femtosecond to Second Studies of Complete ADEKA-1 Sensitized Solar Cells

Ulf Anders Hagfeldt, Enrico Polanski, Jan Ernest Sobus

Record laboratory efficiencies of dye-sensitized solar cells have been recently reported using an alkoxysilyl-anchor dye, ADEKA-1 (over 14%). In this work we use time-resolved techniques to study the impact of key preparation factors (dye synthesis route, ...

Wiley-Blackwell2016

A small electron donor in cobalt complex electrolyte significantly improves efficiency in dye-sensitized solar cells

Ulf Anders Hagfeldt, Yasemin Saygili, Lei Zhang, Yan Hao

Photoelectrochemical approach to solar energy conversion demands a kinetic optimization of various light-induced electron transfer processes. Of great importance are the redox mediator systems accomplishing the electron transfer processes at the semiconduc ...

Nature Publishing Group2016

Effect of metal cation replacement on the electronic structure of metalorganic halide perovskites: Replacement of lead with alkaline-earth metals

Ulf Anders Hagfeldt, Tor Jesper Jacobsson

Organic and inorganic lead halogen perovskites, and in particular, CH3NH3PbI3, have during the last years emerged as a class of highly efficient solar cell materials. Herein we introduce metalorganic halogen perovskite materials for energy-relevant applica ...

Amer Physical Soc2016

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

Towards optical optimization of planar monolithic perovskite/silicon-heterojunction tandem solar cells

Michael Graetzel, Ulf Anders Hagfeldt, Juan-Pablo Correa-Baena, Michael Saliba

Combining inorganic-organic perovskites and crystalline silicon into a monolithic tandem solar cell has recently attracted increased attention due to the high efficiency potential of this cell architecture. Promising results with published efficiencies abo ...

Iop Publishing Ltd2016

Enhanced electronic properties in mesoporous TiO2 via lithium doping for high-efficiency perovskite solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Fabrizio Giordano, Juan-Pablo Correa-Baena, Antonio Abate, Taisuke Matsui, Michael Saliba

Perovskite solar cells are one of the most promising photovoltaic technologies with their extraordinary progress in efficiency and the simple processes required to produce them. However, the frequent presence of a pronounced hysteresis in the current volta ...

Nature Publishing Group2016

Mesoporous carbon-imbedded W2C composites as flexible counter electrodes for dye-sensitized solar cells

Ulf Anders Hagfeldt, Weiwei Zhang

Mesoporous carbon (MC)-imbedded tungsten carbide (W2C) composites are synthesized via a simple methodology and subsequently used as flexible counter electrodes (CEs) in dye-sensitized solar cells (DSCs). The W2C/MC composite possesses remarkable electroche ...

Royal Society of Chemistry2016

Low-cost Cr doped Pt3Ni alloy supported on carbon nanofibers composites counter electrode for efficient dye-sensitized solar cells

Ulf Anders Hagfeldt, Weiwei Zhang, Mei Wang

Pt3Ni alloy supported by carbon nanofibers (CNs) composites (Pt3Ni/CNs) synthesized by a simple solvothermal process was introduced into dye-sensitized solar cells (DSCs) as counter electrode (CE) for the first time, and the DSCs based on Pt3Ni/CNs CE obta ...

Elsevier Science Bv2016

Highly effective Co3S4/electrospun-carbon-nanofibers composite counter electrode synthesized with electrospun technique for cobalt redox electrolyte based on dye-sensitized solar cells

Ulf Anders Hagfeldt, Weiwei Zhang

The composite of cobaltosic sulfide/electrospun carbon nanofibers (Co3S4/ECs) with high catalytic activity have been successfully synthesized by combining the versatility of the electrospunning technique and following a hydrothermal synthesis method. And t ...

Elsevier Science Bv2016

Properties of Contact and Bulk Impedances in Hybrid Lead Halide Perovskite Solar Cells Including Inductive Loop Elements

Ulf Anders Hagfeldt, Juan-Pablo Correa-Baena, Tor Jesper Jacobsson

Impedance spectroscopy offers access to all the different electronic and ionic processes taking place simultaneously in an operating solar cell. To date, its use on perovskite solar cells has been challenging because of the richness of the physical process ...

Amer Chemical Soc2016

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