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Ulf Anders Hagfeldt

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Related publications (296)

Thermodynamic stability screening of IR-photonic processed multication halide perovskite thin films

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Sandy Sanchez Alonso, Natalie Flores Diaz, Pascal Alexander Schouwink, Brian Irving Carlsen

We report a material screening study for phase transitions of multication hybrid halide perovskite films. Two hundred sixty-six films processed with flash infrared annealing were optically and structurally characterized. This data was compiled into a datab ...

Royal Society of Chemistry2021

Stable Layered 2D Perovskite Solar Cells with an Efficiency of over 19% via Multifunctional Interfacial Engineering

Ulf Anders Hagfeldt, Dongqin Bi

Layered 2D perovskites have been extensively investigated by scientists with photovoltaics (PV) expertise due to their good environmental stability. However, a random phase distribution in the perovskite film could affect both the performance and stability ...

AMER CHEMICAL SOC2021

Rapid hybrid perovskite film crystallization from solution

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Sandy Sanchez Alonso, Lukas Pfeifer

The use of a solution process to grow perovskite thin films allows to extend the material processability. It is known that the physicochemical properties of the perovskite material can be tuned by altering the solution precursors as well as by controlling ...

Royal Society of Chemistry2021

Synergistic Effect of Fluorinated Passivator and Hole Transport Dopant Enables Stable Perovskite Solar Cells with an Efficiency Near 24%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Linfeng Pan, Yuhang Liu, Felix Thomas Eickemeyer, Yameng Ren, Hongwei Zhu, Olivier Ouellette

Long-term durability is critically important for the commercialization of perovskite solar cells (PSCs). The ionic character of the perovskite and the hydrophilicity of commonly used additives for the hole-transporting layer (HTL), such as lithium bis(trif ...

2021

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

Ulf Anders Hagfeldt, Dongqin Bi, Haibing Xie

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

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

Xanthan-Based Hydrogel for Stable and Efficient Quasi-Solid Truly Aqueous Dye-Sensitized Solar Cell with Cobalt Mediator

Michael Graetzel, Guido Viscardi, Ulf Anders Hagfeldt, Fabrizio Giordano

Aqueous dye-sensitized solar cells (DSSCs) are emerging as a promising alternative to enhance both the lifetime and environmental friendliness of traditional DSSCs. Herein, a cobalt-based, jellified (with xanthan gum) aqueous electrolyte, leading to a valu ...

WILEY-V C H VERLAG GMBH2021

Supramolecular Co-adsorption on TiO2 to enhance the efficiency of dye-sensitized solar cells

Ulf Anders Hagfeldt

Three novel push-pull dyes, with carbazole donors, coded AJ502, TZ101 and TZ102 are synthesized and applied as co-sensitizers in dye-sensitized solar cells (DSSCs). TZ101 and TZ102 have similar structures except for two fluorine atoms introduced on the ben ...

Royal Society of Chemistry2021

Interfacial versus Bulk Properties of Hole-Transporting Materials for Perovskite Solar Cells: Isomeric Triphenylamine-Based Enamines versus Spiro-OMeTAD

Ulf Anders Hagfeldt, Bowen Yang, Yeonju Kim, Jiajia Suo

Here, we report on three new triphenylamine-based enamines synthesized by condensation of an appropriate primary amine with 2,2-diphenylacetaldehyde and characterized by experimental techniques and density functional theory (DFT) computations. Experimental ...

AMER CHEMICAL SOC2021

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

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

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

Hydrophobic Organic Ammonium Halide Modification toward Highly Efficient and Stable CsPbI(2.25)Br(0.75 )Solar Cell

Ulf Anders Hagfeldt, Zaiwei Wang

Inorganic cesium lead halide perovskite solar cells are promising candidates for next-generation photovoltaic applications. However, their phase instability and relatively low efficiency hinder their commercialization. Herein, hydrophobic organic ammonium ...

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, Seyyed Alireza Hashemi

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

Decorated graphene oxide flakes with integrated complex of 8-hydroxyquinoline/NiO toward accurate detection of glucose at physiological conditions

Ulf Anders Hagfeldt, Seyyed Alireza Hashemi

The dramatic increase in the number of diabetic people raised the requirement for developing practical diagnostic setups capable of rapid and precise detection of glucose molecules at physiological conditions through non-enzymatic approaches. To address th ...

ELSEVIER SCIENCE SA2021

Low-Cost Dopant Additive-Free Hole-Transporting Material for a Robust Perovskite Solar Cell with Efficiency Exceeding 21%

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Linfeng Pan, Yuhang Liu, Felix Thomas Eickemeyer, Yameng Ren, Hongwei Zhu, Zhongjin Shen

Developing hole-transporting materials (HTMs) with appropriate molecular configuration and charge mobility is important to improve perovskite solar cell (PSC) photovoltaic performance and their feasibility for commercialization. In this work, a novel pyram ...

2021

Anchoring single platinum atoms onto nickel nanoparticles affords highly selective catalysts for lignin conversion

Gabor Laurenczy, Paul Joseph Dyson, Zhaofu Fei, Ulf Anders Hagfeldt, Antoine Philippe Van Muyden, Linfeng Pan, Lichen Bai, Lu Chen, Jun Li, Yun Tong

Due to the highly complex polyphenolic structure of lignin, depolymerization without a prior chemical treatment is challenging, and new catalysts are required. Atomically dispersed catalysts are able to maximize the atomic efficiency of noble metals, simul ...

ELSEVIER2021

Guanine‐Stabilized Formamidinium Lead Iodide Perovskites

Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Amita Ummadisingu, Marko Mladenovic, Dominik Józef Kubicki, David Lyndon Emsley, Linfeng Pan, Paramvir Ahlawat, Yuhang Liu, Jovana Milic, Dan Ren, Li Hong, Marco Alejandro Ruiz Preciado

Formamidinium (FA) lead iodide perovskite materials feature promising photovoltaic performances and superior thermal stabilities. However, conversion of the perovskite α‐FAPbI3 phase to the thermodynamically stable yet photovoltaically inactive δ‐FAPbI3 ph ...

2020

Consensus statement for stability assessment and reporting for perovskite photovoltaics based on ISOS procedures

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Henry Snaith, Konrad Domanski, Wolfgang Richard Tress, Antonio Abate, Michael Saliba, Monica Marcela Lira Cantu, Haibing Xie, Kai Zhu

Improving the long-term stability of perovskite solar cells is critical to the deployment of this technology. Despite the great emphasis laid on stability-related investigations, publications lack consistency in experimental procedures and parameters repor ...

NATURE PUBLISHING GROUP2020

Tailored Amphiphilic Molecular Mitigators for Stable Perovskite Solar Cells with 23.5% Efficiency

Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Mohammad Ibrahim Dar, Xiong Li, Xiaofei Dong, Linfeng Pan, Zaiwei Wang, Yuhang Liu, Brian Irving Carlsen, Dan Ren, Marco Alejandro Ruiz Preciado, Bowen Yang, Felix Thomas Eickemeyer, Hongwei Zhu, Shilong Wang

Passivation of interfacial defects serves as an effective means to realize highly efficient and stable perovskite solar cells (PSCs). However, most molecular modulators currently used to mitigate such defects form poorly conductive aggregates at the perovs ...

Wiley2020

Vapor-assisted deposition of highly efficient, stable black-phase FAPbI(3) perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Xiong Li, Wolfgang Richard Tress, David Lyndon Emsley, Paramvir Ahlawat, Claudia Esther Avalos, Zaiwei Wang, Yuhang Liu, Anand Agarwalla, Brian Irving Carlsen, Fan Fu, Aditya Mishra, Haizhou Lu, Felix Thomas Eickemeyer, Xianfu Zhang, Likai Zheng, Ying Yang

Mixtures of cations or halides with FAPbI(3) (where FA is formamidinium) lead to high efficiency in perovskite solar cells (PSCs) but also to blue-shifted absorption and long-term stability issues caused by loss of volatile methylammonium (MA) and phase se ...

American Association for the Advancement of Science2020

Compositional and Interface Engineering of Organic-Inorganic Lead Halide Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Haizhou Lu, Anurag Krishna

Power conversion efficiency (PCE) of the perovskite solar cells (PSCs) has remarkably been increased from3.1%to 25.2%. The fast expansion of the PSCs has been along with the development of compositional and interface engineering, which has been playing a c ...

2020

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