Publications de Bowen Yang | EPFL Graph Search

Multifunctional sulfonium-based treatment for perovskite solar cells with less than 1% efficiency loss over 4,500-h operational stability tests

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

The stabilization of grain boundaries and surfaces of the perovskite layer is critical to extend the durability of perovskite solar cells. Here we introduced a sulfonium-based molecule, dimethylphenethylsulfonium iodide (DMPESI), for the post-deposition tr ...

Nature Portfolio2024

A universal ligand for lead coordination and tailored crystal growth in perovskite solar cells

Ulf Anders Hagfeldt, Bowen Yang, Jiajia Suo

Chemical environment and precursor-coordinating molecular interactions within a perovskite precursor solution can lead to important implications in structural defects and crystallization kinetics of a perovskite film. Thus, the opto-electronic quality of s ...

Royal Soc Chemistry2024

Overcome Low Intrinsic Conductivity of NiOx Through Triazinyl Modification for Highly Efficient and Stable Inverted Perovskite Solar Cells

Ulf Anders Hagfeldt, Hui Chen, Jiabao Yang, Tong Wang, Bowen Yang

Nickel oxide (NiOx) is a promising hole transport material in inverted organic-inorganic metal halide perovskite solar cells. However, its low intrinsic conductivity hinders its further improvement in device performance. Here, we employ a trimercapto-s-tri ...

WILEY-V C H VERLAG GMBH2022

Inhibiting metal-inward diffusion-induced degradation through strong chemical coordination toward stable and efficient inverted perovskite solar cells

Ulf Anders Hagfeldt, Bowen Yang

The inward diffusion of metal electrodes is one of the main reasons for the deterioration of the long-term device stability of perovskite solar cells (PSCs). Thus, herein, we adopt a simple additive engineering strategy to modify the barrier material batho ...

ROYAL SOC CHEMISTRY2022

Interfacial engineering from material to solvent: A mechanistic understanding on stabilizing alpha-formamidinium lead triiodide perovskite photovoltaics

Michael Graetzel, Ulf Anders Hagfeldt, Bowen Yang, Jiajia Suo, Jaeki Jeong

Formamidinium lead triiodide (FAPbI3) has recently been considered as the most promising candidate to achieve highly efficient perovskite solar cells (PSCs). Excitingly, the state-of-the-art highest efficiency of FAPbI3 based PSCs have reached over 25%. Ho ...

Elsevier2022

Gradient Heating Epitaxial Growth Gives Well Lattice-Matched Mo2C-Mo2N Heterointerfaces that Boost Both Electrocatalytic Hydrogen Evolution and Water Vapor Splitting

Bowen Yang, Mei Wang, Peng Guo

An optimized approach to producing lattice-matched heterointerfaces for electrocatalytic hydrogen evolution has not yet been reported. Herein, we present the synthesis of lattice-matched Mo2C-Mo2N heterostructures using a gradient heating epitaxial growth ...

Wiley-VCH Verlag GmbH2022

Molecularly Engineered Low-Cost Organic Hole-Transporting Materials for Perovskite Solar Cells: The Substituent Effect on Non-fused Three-Dimensional Systems

Michael Graetzel, Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Brian Irving Carlsen, Bowen Yang, Jiajia Suo

In this work, we describe a new class of non-fused 3D asymmetric compounds (named 1, 2, 3, and 4) as low-cost organic hole-transporting materials (HTMs) for perovskite solar cells (PSCs). The fundamental understanding of the influence of the methylthio and ...

AMER CHEMICAL SOC2022

Perovskite Solar Cells with Carbon-Based Electrodes - Quantification of Losses and Strategies to Overcome Them

Ulf Anders Hagfeldt, Dmitry Bogachuk, Bowen Yang, Jiajia Suo

Carbon-based electrodes represent a promising approach to improve stability and up-scalability of perovskite photovoltaics. The temperature at which these contacts are processed defines the absorber grain size of the perovskite solar cell: in cells with lo ...

WILEY-V C H VERLAG GMBH2022

Strain effects on halide perovskite solar cells

Mohammad Khaja Nazeeruddin, Ulf Anders Hagfeldt, Hobeom Kim, Bowen Yang, Jiajia Suo

Halide perovskite solar cells (PSCs) have achieved power conversion efficiencies (PCEs) approaching 26%, however, the stability issue hinders their commercialization. Due to the soft ionic nature of perovskite materials, the strain effect on perovskite fil ...

Royal Society of Chemistry2022

Urea Derivative-Promoted CsPbl(2)Br Perovskite Solar Cells with High Open-Circuit Voltage

Xin Guo, Bowen Yang, Yang Liu, Chen Li

Inorganic perovskite solar cells (PSCs) have witnessed extraordinary advances owing to their prominent stability against thermal aging. However, they suffer from a phase transition from black phase to yellow phase under ambient conditions and serious energ ...

WILEY-V C H VERLAG GMBH2022

Ion-modulated radical doping of spiro-OMeTAD for more efficient and stable perovskite solar cells

Ulf Anders Hagfeldt, Bowen Yang, Jiajia Suo

Record power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have been obtained with the organic hole transporter 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene (spiro-OMeTAD). Conventional doping of spiro-OMeTAD with ...

American Association for the Advancement of Science2022

Hysteresis-Free Planar Perovskite Solar Module with 19.1% Efficiency by Interfacial Defects Passivation

Ulf Anders Hagfeldt, Bowen Yang, Jiajia Suo

In few years, perovskite solar devices have reached high efficiency on lab scale cells. Upscaling to module size, effective perovskite recipe and posttreatment are of paramount importance to the breakthrough of the technology. Herein this work, the develop ...

WILEY-V C H VERLAG GMBH2022

Additives-free indolo[3,2-b]carbazole-based hole-transporting materials for perovskite solar cells with three yeses: Stability, efficiency, simplicity

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

Indolo[3,2-b]carbazole-based hole transporting materials (HTM1-3) are developed for dopant-free pemvskite solar cells (PSCs). The newly synthesized compounds are studied as alternatives of conventional hole-transporting materials which typically require ad ...

Elsevier2022

An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

Ulf Anders Hagfeldt, Barbara Alexandra Primera Darwich, Bowen Yang

Making large datasets findable, accessible, interoperable and reusable could accelerate technology development. Now, Jacobsson et al. present an approach to build an open-access database and analysis tool for perovskite solar cells. ...

NATURE PORTFOLIO2022

N-Type Conductive Small Molecule Assisted 23.5% Efficient Inverted Perovskite Solar Cells

Ulf Anders Hagfeldt, Hui Chen, Jiabao Yang, Hadi Salari, Xiong Li, Tong Wang, Bowen Yang

Because of the compatibility with tandem devices and the ability to be manufactured at low temperatures, inverted perovskite solar cells have generated far-ranging interest for potential commercial applications. However, their efficiency remains inadequate ...

WILEY-V C H VERLAG GMBH2022

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

Ulf Anders Hagfeldt, Hui Chen, Jiabao Yang, Tong Wang, Bowen Yang

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

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

Surface Reconstruction Engineering with Synergistic Effect of Mixed‐Salt Passivation Treatment toward Efficient and Stable Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Filippo de Angelis, Hui-Seon Kim, Bowen Yang, Yeonju Kim, Jiajia Suo

Surface passivation treatment is a widely used strategy to resolve trap-mediated nonradiative recombination toward high-efficiency metal-halide perovskite photovoltaics. However, a lack of passivation with mixture treatment has been investigated, as well a ...

2021

Dion-Jacobson and Ruddlesden-Popper double-phase 2D perovskites for solar cells

Sajjad Ahmad, Xin Guo, Bowen Yang, Yang Liu, Chen Li

Dion-Jacobson (DJ) phase and Ruddlesden-Popper phase 2D perovskites have been, individually, demonstrated to be more stable than 3D counterparts for perovskite solar cells (PSCs). In order to further improve the efficiency and stability of 2D PSCs, we here ...

Elsevier2021

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