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Ulf Anders Hagfeldt

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Related publications (296)

Benzylammonium‐Mediated Formamidinium Lead Iodide Perovskite Phase Stabilization for Photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Dominik Józef Kubicki, David Lyndon Emsley, Zaiwei Wang, Anwar Qasem M Alanazi, Jovana Milic, Dan Ren, Masaud Hassan S Almalki, Aditya Mishra, Felix Thomas Eickemeyer, Hong Zhang

There is an ongoing surge of interest in the use of formamidinium (FA) lead iodide perovskites in photovoltaics due to their exceptional optoelectronic properties. However, thermodynamic instability of the desired cubic perovskite (α-FAPbI3) phase at ambie ...

2021

An experimental and theoretical exploration of the role of tri-element metal-nonmetal nanohybrids in photovoltaics

Ulf Anders Hagfeldt

Inexpensive electrocatalysts with excellent catalytic activity as the counter electrodes (CEs) are crucial for the commercialization of solar cells. Herein, we report a unique rhombic dodecahedron framework of N-doped porous carbon loaded with 0.66 wt% Fe ...

ELSEVIER SCIENCE SA2021

Flash Infrared Annealing for Perovskite Solar Cell Processing

Ulf Anders Hagfeldt, Sandy Sanchez Alonso

Organic-inorganic perovskites have an impressive potential for the design of next generation solar cells and are currently considered for upscaling and commercialization. Currently, perovskite solar cells rely on spin-coating which is neither practical for ...

JOURNAL OF VISUALIZED EXPERIMENTS2021

Co-doped magnetic N-TiO2-x/rGO heterojunction@cellulose nanofibrous flakelet for enhanced photocatalytic oxidation and facile separation: Efficient charge separation and self-floatability

Ulf Anders Hagfeldt

Visible-light-absorbing N-TiO2-x/rGO@cellulose nanohybrid photocatalyst with magnetism and self-floatability was fabricated via a facile in-situ nanocomposite strategy. The co-doping levels of nitrogen and oxygen vacancies formed bandgap states highly broa ...

ELSEVIER SCIENCE SA2021

Methylammonium Triiodide for Defect Engineering of High-Efficiency Perovskite Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Mounir Driss Mensi, Ursula Röthlisberger, Ulf Anders Hagfeldt, Thomas Paul Baumeler, Linfeng Pan, Paramvir Ahlawat, Claudia Esther Avalos, Essa Awadh R Alharbi, Pascal Alexander Schouwink, George Cameron Fish, Mathias Dankl, Bowen Yang, Felix Thomas Eickemeyer, Viktor Skorjanc, Anurag Krishna, Olivier Ouellette, Elsa John, Lukas Pfeifer

The defects present in metal halide perovskite are deleterious to both the performance and stability of photovoltaic devices. Consequently, there is an intense focus on developing defect mitigation strategies. Herein we report a facile strategy that employ ...

2021

Copolymer-Templated Nickel Oxide for High-Efficiency Mesoscopic Perovskite Solar Cells in Inverted Architecture

Michael Graetzel, Ulf Anders Hagfeldt, Wolfgang Richard Tress, Marco Alejandro Ruiz Preciado, Hong Zhang

Despite the outstanding role of mesoscopic structures on the efficiency and stability of perovskite solar cells (PSCs) in the regular (n-i-p) architecture, mesoscopic PSCs in inverted (p-i-n) architecture have rarely been reported. Herein, an efficient and ...

WILEY-V C H VERLAG GMBH2021

Nanoscale interfacial engineering enables highly stable and efficient perovskite photovoltaics

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

When photoluminescence, electroluminescence, and open-circuit voltage diverge - light soaking and halide segregation in perovskite solar cells

Ulf Anders Hagfeldt, Wolfgang Richard Tress, Bowen Yang, Yeonju Kim

Perovskite solar cells suffer from various instabilities on all time scales. Some of them are driven by light, in particular when employing compounds with mixed halides. Such light soaking effects have been observed to result in performance changes of sola ...

Royal Society of Chemistry2021

Nanoscale Phase Segregation in Supramolecular π-Templating for Hybrid Perovskite Photovoltaics from NMR Crystallography

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Marko Mladenovic, Dominik Józef Kubicki, Manuel Cordova, David Lyndon Emsley, Farzaneh Jahanbakhshi, Paramvir Ahlawat, Loï Charles Carbone, Yuhang Liu, Brian Irving Carlsen, Jovana Milic, Rashmi Runjhun, Aditya Mishra, Toru Nakamura, Michael Allan Hope, Thomas Schneeberger

The use of layered perovskites is an important strategy to improve the stability of hybrid perovskite materials and their optoelectronic devices. However, tailoring their properties requires accurate structure determination at the atomic scale, which is a ...

2021

Thiophene-fused carbazole derivative dyes for high-performance dye-sensitized solar cells

Ulf Anders Hagfeldt

Two novel dyes that are similar in chemical structure, except for different donor units, AJ301and AJ303 were synthesized, characterized and applied as sensitizers in dye-sensitized solar cells (DSSCs). Both dyes exhibited a wide absorption of visible sunli ...

PERGAMON-ELSEVIER SCIENCE LTD2021

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, Dominik Józef Kubicki, David Lyndon Emsley, Hui-Seon Kim, Zaiwei Wang, 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

Formation of High-Performance Multi-Cation Halide Perovskites Photovoltaics by delta-CsPbI3/delta-RbPbI3 Seed-Assisted Heterogeneous Nucleation

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mounir Driss Mensi, Ulf Anders Hagfeldt, Thomas Paul Baumeler, Linfeng Pan, Essa Awadh R Alharbi, Zaiwei Wang, Masaud Hassan S Almalki, Bowen Yang, Felix Thomas Eickemeyer, Anurag Krishna, Olivier Ouellette

The performance of perovskite solar cells is highly dependent on the fabrication method; thus, controlling the growth mechanism of perovskite crystals is a promising way towards increasing their efficiency and stability. Herein, a multi-cation halide compo ...

2021

Toward highly efficient and stable Sn2+ and mixed Pb2+/Sn2+ based halide perovskite solar cells through device engineering

Ulf Anders Hagfeldt

Lead halide perovskite (LHP) has gained tremendous attention from both academia and industry due to its excellent optical and electrical properties. To date, the power conversion efficiency (PCE) of a small area LHP solar cell has reached 25.5%. However, l ...

ROYAL SOC CHEMISTRY2021

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

Microbial bioelectrochemical cells for hydrogen generation based on irradiated semiconductor photoelectrodes

Nikolaos Vlachopoulos, Fabian Fischer, Ulf Anders Hagfeldt, Michele Morgante

In recent years, one of the most important challenges of the 21st century is to satisfy the ever-increasing world's energy demand. Many efforts are being undertaken to find alternative renewable energy sources, which ideally should outcompete fossil fuel u ...

IOP PUBLISHING LTD2021

The Rise of Dye-Sensitized Solar Cells: From Molecular Photovoltaics to Emerging Solid-State Photovoltaic Technologies

Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Marko Stojanovic, Natalie Flores Diaz, Yuhang Liu, Jovana Milic, Yameng Ren, Zhongjin Shen, Lukas Pfeifer

Over the past three decades, dye-sensitized solar cells (i. e. Gratzel cells) have evolved from a pioneering concept of molecular photovoltaics to large-scale industrial deployment. In this review article, we provide a historical overview of the developmen ...

WILEY-V C H VERLAG GMBH2021

A combined molecular dynamics and experimental study of two-step process enabling low-temperature formation of phase-pure α-FAPbI3

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Paramvir Ahlawat, Essa Awadh R Alharbi, Haizhou Lu

It is well established that the lack of understanding the crystallization process in a two-step sequential deposition has a direct impact on efficiency, stability, and reproducibility of perovskite solar cells. Here, we try to understand the solid-solid ph ...

2021

Formation and Stabilization of Inorganic Halide Perovskites for Photovoltaics

Ulf Anders Hagfeldt, Zaiwei Wang, Wanchun Xiang, Jiahuan Zhang

In the last decade, halide perovskites have emerged as new semiconductors that revolutionize the photovoltaic field. Among this family of materials, all-inorganic halide perovskites are becoming a research paradigm because of their outstanding photophysica ...

ELSEVIER2021

Photoelectrochemical Water-Splitting Using CuO-Based Electrodes for Hydrogen Production: A Review

Ulf Anders Hagfeldt

The cost-effective, robust, and efficient electrocatalysts for photoelectrochemical (PEC) water-splitting has been extensively studied over the past decade to address a solution for the energy crisis. The interesting physicochemical properties of CuO have ...

Wiley-V C H Verlag Gmbh2021

Interfacial Passivation Engineering of Perovskite Solar Cells with Fill Factor over 82% and Outstanding Operational Stability on n-i-p Architecture

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Bowen Yang, Yeonju Kim, Jiajia Suo

Tremendous efforts have been dedicated toward minimizing the open-circuit voltage deficits on perovskite solar cells (PSCs), and the fill factors are still relatively low. This hinders their further application in large scalable modules. Herein, we employ ...

AMER CHEMICAL SOC2021

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