Chongwen Li

Northwestern University

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Yanfa Yan

University of Toledo

Zhaoning Song

University of Toledo

Randy J. Ellingson

University of Toledo

Hao Chen

Taiyuan University of Technology

Lei Chen

Henan Normal University

Edward H. Sargent

University of Toronto

Bin Chen

Northwestern University

Nikolas J. Podraza

University of Toledo

Aidan Maxwell

University of Toronto

Zaiwei Wang

University of Toronto

Cooperative Institutions

University of Toledo

National Renewable Energy Laboratory

Chinese Academy of Sciences

University of Toronto

Northwestern University

King Abdullah University of Science and Technology

University of Colorado Boulder

École Polytechnique Fédérale de Lausanne

University of Chinese Academy of Sciences

Oak Ridge National Laboratory

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Multifunctional Regulation of Highly Orientated Tin–Lead Alloyed Perovskite Solar Cells

ACS Energy Letters (2023)

Xiafei Jiang Chongwen Li Xianzhao Wang Cheng Peng Haokun Jiang

Tin–lead (Sn–Pb) alloyed perovskites are promising candidates for next-generation photovoltaics due to their appropriate bandgaps for multijunction tandem solar cells, which can potentially overcome the Shockley-Queisser limit. However, their power conversion efficiency (PCE) and stability are still impeded by the poor absorber quality and defects caused by the oxidation of Sn2+. Here, we introduced trimethylsulfoxonium iodide (TMSI) as an additive along with SnF2 to fabricate Sn–Pb perovskite films with enlarged grains and improved film quality. TMSI restrained the oxidation of Sn2+ through molecular interactions, reducing the formation of detrimental Sn vacancies. As a result, a highly oriented Sn–Pb alloyed perovskite with a lower defect density was obtained, along with suppressed ion migration. The TMSI-treated Sn–Pb-based devices exhibited a champion PCE of 22.6% and outstanding stability, retaining 83% of their original efficiency after 6000 h of storage under a N2 atmosphere and maintaining 88% of their initial value after 1200 h of continuous one-sun illumination.

Tandem

10.1021/acsenergylett.2c02576

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Citations (41)

The dynamic adsorption affinity of ligands is a surrogate for the passivation of surface defects

Nature Communications (2024)

Jian Xu Aidan Maxwell Zhaoning Song Abdulaziz S. R. Bati Hao Chen

Surface defects in semiconducting materials, though they have been widely studied, remain a prominent source of loss in optoelectronic devices; here we sought a new angle of approach, looking into the dynamic roles played by surface defects under atmospheric stressors and their chemical passivants in the lifetime of optoelectronic materials. We find that surface defects possess properties distinct from those of bulk defects. ab initio molecular dynamics simulations reveal a previously overlooked reversible degradation mechanism mediated by hydrogen vacancies. We find that dynamic surface adsorption affinity (DAA) relative to surface treatment ligands is a surrogate for passivation efficacy, a more strongly-correlated feature than is the static binding strength emphasized in prior reports. This guides us to design targeted passivator ligands with high molecular polarity: for example, 4-aminobutylphosphonic acid exhibits strong DAA and provides defect passivation applicable to a range of perovskite compositions, including suppressed hydrogen vacancy formation, enhanced photovoltaic performances and operational stability in perovskite solar cells.

Passivation

Degradation

10.1038/s41467-024-46368-8

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Citations (5)

Rational design of Lewis base molecules for stable and efficient inverted perovskite solar cells

Science (2023)

Chongwen Li Xiaoming Wang Enbing Bi Fangyuan Jiang So Min Park

Lewis base molecules that bind undercoordinated lead atoms at interfaces and grain boundaries (GBs) are known to enhance the durability of metal halide perovskite solar cells (PSCs). Using density functional theory calculations, we found that phosphine-containing molecules have the strongest binding energy among members of a library of Lewis base molecules studied herein. Experimentally, we found that the best inverted PSC treated with 1,3-bis(diphenylphosphino)propane (DPPP), a diphosphine Lewis base that passivates, binds, and bridges interfaces and GBs, retained a power conversion efficiency (PCE) slightly higher than its initial PCE of ~23% after continuous operation under simulated AM1.5 illumination at the maximum power point and at ~40°C for >3500 hours. DPPP-treated devices showed a similar increase in PCE after being kept under open-circuit conditions at 85°C for >1500 hours.

Base (topology)

Rational design

10.1126/science.ade3970

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Citations (353)

All-Perovskite Tandem Photoelectrodes for Unassisted Solar Hydrogen Production

ACS Energy Letters (2023)

Zhaoning Song Chongwen Li Lei Chen Kshitiz Dolia Sheng Fu

Unassisted solar water splitting by multijunction tandem photoelectrodes is a sustainable approach to generating green hydrogen fuels. Here, we report on the fabrication of monolithically integrated all-perovskite tandem photocathodes for efficient unassisted solar water splitting. All-perovskite tandem photocathodes wired to an iridium oxide anode deliver a high photovoltage of more than 2 V with an operating photocurrent density of 12.5 mA cm–2 at zero applied bias under simulated AM1.5G 1 sun illumination, yielding a solar-to-hydrogen (STH) conversion efficiency of 15%. The tandem photoelectrode demonstrates continuous operation in water for more than 120 h under simulated 1 sun illumination with less than 5% efficiency loss. A technoeconomic analysis shows the projected production cost of all-perovskite tandem photoelectrodes is $30 m–2, promising a levelized cost of hydrogen of less than $1/kg if sufficient device longevity is realized. This work provides a path toward achieving cost-effective unassisted solar hydrogen fuel production.

Tandem

Photocurrent

Photocathode

Solar fuel

10.1021/acsenergylett.3c00654

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Citations (19)

Publisher Correction: Regulating surface potential maximizes voltage in all-perovskite tandems

Nature (2023)

Hao Chen Aidan Maxwell Chongwen Li Sam Teale Bin Chen

10.1038/s41586-023-06450-5

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Citations (4)

Diamine chelates for increased stability in mixed Sn–Pb and all-perovskite tandem solar cells

Nature Energy (2024)

Chongwen Li Lei Chen Fangyuan Jiang Zhaoning Song Xiaoming Wang

Passivation

Tandem

Stoichiometry

10.1038/s41560-024-01613-8

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Citations (17)

Probing the origins of photodegradation in organic–inorganic metal halide perovskites with time-resolved mass spectrometry

Sustainable Energy & Fuels (2018)

Zhaoning Song Changlei Wang Adam B. Phillips Corey R. Grice Dewei Zhao

Our mass spectrometry measurements indicate that the hot-carrier-induced deprotonation of MA⁺cations is the fundamental origin of photodegradation.

Photodegradation

Metal halides

10.1039/c8se00358k

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Citations (97)

Binary hole transport materials blending to linearly tune HOMO level for high efficiency and stable perovskite solar cells

Nano Energy (2018)

Xinxing Yin Changlei Wang Dewei Zhao Niraj Shrestha Corey R. Grice

10.1016/j.nanoen.2018.07.027

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Citations (64)

Reducing Saturation‐Current Density to Realize High‐Efficiency Low‐Bandgap Mixed Tin–Lead Halide Perovskite Solar Cells

Advanced Energy Materials (2018)

Chongwen Li Zhaoning Song Dewei Zhao Chuanxiao Xiao Biwas Subedi

Abstract The unsatisfactory performance of low‐bandgap mixed tin (Sn)–lead (Pb) halide perovskite subcells has been one of the major obstacles hindering the progress of the power conversion efficiencies (PCEs) of all‐perovskite tandem solar cells. By analyzing dark‐current density and distribution, it is identified that charge recombination at grain boundaries is a key factor limiting the performance of low‐bandgap mixed Sn–Pb halide perovskite subcells. It is further found that bromine (Br) incorporation can effectively passivate grain boundaries and lower the dark current density by two–three orders of magnitude. By optimizing the Br concentration, low‐bandgap (1.272 eV) mixed Sn–Pb halide perovskite solar cells are fabricated with open‐circuit voltage deficits as low as 0.384 V and fill factors as high as 75%. The best‐performing device demonstrates a PCE of >19%. The results suggest an important direction for improving the performance of low‐bandgap mixed Sn–Pb halide perovskite solar cells.

Saturation current

Passivation

Saturation (graph theory)

Tandem

10.1002/aenm.201803135

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Citations (326)

Low-bandgap mixed tin–lead iodide perovskites with reduced methylammonium for simultaneous enhancement of solar cell efficiency and stability

Nature Energy (2020)

Chongwen Li Zhaoning Song Cong Chen Chuanxiao Xiao Biwas Subedi

Formamidinium

Tandem

Perovskite solar cell

Passivation

10.1038/s41560-020-00692-7

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Citations (211)