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Ulf Anders Hagfeldt

Cette personne a quitté l’EPFL

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Publications associées (296)

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Directly Photoexcited Oxides for Photoelectrochemical Water Splitting

Ulf Anders Hagfeldt, Nikolaos Vlachopoulos, Linfeng Pan

Artificial photosynthesis promises to become a sustainable way to harvest solar energy and store it in chemical fuels by means of photoelectrochemical (PEC) cells. Although it is intriguing to shift the fossil-fuel-based economy to a renewable carbon-neutr ...

WILEY-V C H VERLAG GMBH2019

Unreacted PbI2 as a Double-Edged Sword for Enhancing the Performance of Perovskite Solar Cells

Ulf Anders Hagfeldt, Jacques-Edouard Moser, Kurt Schenk, Wolfgang Richard Tress, Joël Teuscher, Juan-Pablo Correa-Baena, Marine Eva Fedora Bouduban, Tor Jesper Jacobsson

Lead halide perovskites have over the past few years attracted considerable interest as photo absorbers in PV applications with record efficiencies now reaching 22%. It has recently been found that not only the composition but also the precise stoichiometr ...

American Chemical Society2016

Towards Oxide Electronics: a Roadmap

Ulf Anders Hagfeldt, Francisco Sanchez, Mauro Fanciulli

At the end of a rush lasting over half a century, in which CMOS technology has been experiencing a constant and breathtaking increase of device speed and density, Moore's law is approaching the insurmountable barrier given by the ultimate atomic nature of ...

2019

Deep defect passivation and shallow vacancy repair via an ionic silicone polymer toward highly stable inverted perovskite solar cells

Ulf Anders Hagfeldt, Bowen Yang, Hui Chen

Additive engineering is an effective strategy for defect passivation and performance improvement of perovskite solar cells (PSCs). However, few additives have achieved outstanding stability with high efficiency by simultaneously passivating deep and shallo ...

ROYAL SOC CHEMISTRY2022

SnS Quantum Dots as Hole Transporter of Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Peng Wang, Yuhang Liu, Dan Ren, Zaiwei Wang, Yang Li

Perovskite solar cells have achieved comparable power conversion efficiencies as commercial silicon cells, making the issue of long-term operation stability as the most critical scientific factor toward industrial realization. In this work, we introduce Sn ...

AMER CHEMICAL SOC2019

Research data supporting "High carrier mobility along the [111] orientation in Cu2O photoelectrodes"

Michael Graetzel, Paul Joseph Dyson, Ulf Anders Hagfeldt, Jingshan Luo, Dan Ren, Linfeng Pan, Lu Chen, Meng Xia, Wenzhe Niu

Included in the dataset are detailed information into the crystallography, morphology, electronic properties, (photo)electrochemical and carrier dynamics of both single-crystal Cu2O thin films and polycrystalline Cu2O with favored crystal orientations. Mul ...

Apollo - University of Cambridge Repository2024

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

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

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

Decoupling the effects of defects on efficiency and stability through phosphonates in stable halide perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, David Lyndon Emsley, Dominik Józef Kubicki, Zaiwei Wang, Hui-Seon Kim, Anand Agarwalla

Understanding defects is of paramount importance for the development of stable halide perovskite solar cells (PSCs). However, isolating their distinctive effects on device efficiency and stability is currently a challenge. We report that adding the organic ...

CELL PRESS2021

Photoinduced Stark Effects and Mechanism of Ion Displacement in Perovskite Solar Cell Materials

Ulf Anders Hagfeldt, Tor Jesper Jacobsson

Organometallic halide perovskites (OMHPs) have recently emerged as a promising class of materials in photovoltaic technology. Here, we present an in-depth investigation of the physics in these systems by measuring the photoinduced absorption (PIA) in OMHPs ...

Amer Chemical Soc2017

Nanoscale mapping of chemical composition in organic-inorganic hybrid perovskite films

Ulf Anders Hagfeldt, Jorge Miguel Dias Almeida Rodrigues Soares, Rodrigo Szostak

Lead-based organic-inorganic hybrid perovskite (OIHP) solar cells can attain efficiencies over 20%. However, the impact of ion mobility and/or organic depletion, structural changes, and segregation under operating conditions urge for decisive and more accu ...

American Association for the Advancement of Science (AAAS)2019

Toward an alternative approach for the preparation of low-temperature titanium dioxide blocking underlayers for perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Nikolaos Vlachopoulos, Kazuteru Nonomura, Lichen Zhao

The anodic electrodeposition method is investigated as an alternative technique for the preparation of a titanium oxide (TiO2) blocking underlayer (UL) for perovskite solar cells (PSCs). Extremely thin Ti-IV-based films are grown from aqueous acidic titani ...

Royal Society of Chemistry2019

Organic Ammonium Halide Modulators as Effective Strategy for Enhanced Perovskite Photovoltaic Performance

Michael Graetzel, Ulf Anders Hagfeldt, Yuhang Liu, Lukas Pfeifer, Seckin Akin, Bitao Dong

Despite rapid improvements in efficiency, long-term stability remains a challenge limiting the future up-scaling of perovskite solar cells (PSCs). Although several approaches have been developed to improve the stability of PSCs, applying ammonium passivati ...

WILEY2021

Perovskitoid-Templated Formation of a 1D@3D Perovskite Structure toward Highly Efficient and Stable Perovskite Solar Cells

Ulf Anders Hagfeldt, Dongqin Bi

Longevity is a long-standing concern for organic-inorganic hybrid perovskite solar cells (PSCs). Recently, the use of low dimensional perovskite has been proven to be a promising strategy to improve the stability of PSCs. Herein, it is demonstrated that 1D ...

WILEY-V C H VERLAG GMBH2021

Reinforced polypyrrole with 2D graphene flakes decorated with interconnected nickel-tungsten metal oxide complex toward superiorly stable supercapacitor

Ulf Anders Hagfeldt

Prompt development of electronic devices and sensors raised the requirement for design/fabrication of advanced energy sources capable of providing considerable amount of energy for consuming platforms through practical nanotechnological approaches. For thi ...

ELSEVIER SCIENCE SA2021

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

Ulf Anders Hagfeldt, Jingshan Luo, Chenyi Yi, Zaiwei Wang

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

Emerging perovskite quantum dot solar cells: feasible approaches to boost performance

Ulf Anders Hagfeldt

Lead halide perovskite quantum dots (PQDs), also called perovskite nanocrystals, are considered as one of the most promising classes of photovoltaic materials for solar cells due to their prominent optoelectronic properties and simple preparation technique ...

ROYAL SOC CHEMISTRY2021

Nanoscale interfacial engineering enables highly stable and efficient perovskite photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Mounir Driss Mensi, Hong Zhang, Anurag Krishna, Sandy Sanchez Alonso, Mathias Dankl, Olivier Ouellette

We present a facile molecular-level interface engineering strategy to augment the long-term operational and thermal stability of perovskite solar cells (PSCs) by tailoring the interface between the perovskite and hole transporting layer (HTL) with a multif ...

2021

The application of transition metal complexes in hole-transporting layers for perovskite solar cells: Recent progress and future perspectives

Ulf Anders Hagfeldt

In the past few years, the photovoltaic community has witnessed a fast growth of inorganic-organic hybrid perovskite solar cells (PSCs) due to their exceptional power conversion efficiencies with a certified record value exceeding 25%, which rivals the est ...

ELSEVIER SCIENCE SA2020

Triarylamine-based hydrido-carboxylate rhenium(i) complexes as photosensitizers for dye-sensitized solar cells

Ulf Anders Hagfeldt, Thomas Moehl, Kazuteru Nonomura

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

Intrinsic Origin of Superior Catalytic Properties of Tungsten-based Catalysts in Dye-sensitized Solar Cells

Ulf Anders Hagfeldt, Xiao Zhou

To clarify the intrinsic factor of the superior catalytic activity of tungsten (W)-based catalysts in DSSCs, W-based compounds, including W18O49, W2N, WC, and WO3, were prepared as CEs and tested in I-/I-3(-) redox shuttle. A systematic investigation of th ...

Elsevier2017