Guanidinium-Assisted Surface Matrix Engineering for Highly Efficient Perovskite Quantum Dot Photovoltaics

Journal Article · 25 May 2020 · Advanced Materials

DOI: https://doi.org/10.1002/adma.202001906 · OSTI ID:1660019

Ling, Xufeng ^[1]; Yuan, Jianyu ^[1]; Zhang, Xuliang ^[1]; Qian, Yuli ^[1]; Zakeeruddin, Shaik M. ^[2]; Larson, Bryon W. ^[3]; Zhao, Qian ^[3]; Shi, Junwei ^[1]; Yang, Jiacheng ^[1]; Ji, Kang ^[1]; Zhang, Yannan ^[1]; Wang, Yongjie ^[1]; Zhang, Chunyang ^[2]; Duhm, Steffen ^[1]; Luther, Joseph M. ^[3]; Grätzel, Michael ^[2]; Ma, Wanli ^[1]

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1. Soochow Univ., Suzhou (China). Inst. of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Lab. for Carbon‐Based Functional Materials and Devices, Joint International Research Lab. of Carbon‐Based Functional Materials and Devices
2. École Polytechnique Fédérale de Lausanne (EPFL) (Switzerland). Lab. of Photonics and Interfaces (LPI), Inst. of Chemical Sciences and Engineering
3. National Renewable Energy Lab. (NREL), Golden, CO (United States). Chemistry and Nanoscience Center

Metal halide perovskite quantum dots (Pe-QDs) are of great interest in new-generation photovoltaics (PVs). However, it remains challenging in the construction of conductive and intact Pe-QD films to maximize their functionality. Herein, a ligand-assisted surface matrix strategy to engineer the surface and packing states of Pe-QD solids is demonstrated by a mild thermal annealing treatment after ligand exchange processing (referred to as “LE-TA”) triggered by guanidinium thiocyanate. The “LE-TA” method induces the formation of surface matrix on CsPbI₃ QDs, which is dominated by the cationic guanidinium (GA+) rather than the SCN-, maintaining the intact cubic structure and facilitating interparticle electrical interaction of QD solids. Consequently, the GA-matrix-confined CsPbI₃ QDs exhibit remarkably enhanced charge mobility and carrier diffusion length compared to control ones, leading to a champion power conversion efficiency of 15.21% when assembled in PVs, which is one of the highest among all Pe-QD solar cells. Additionally, the “LE-TA” method shows similar effects when applied to other Pe-QD PV systems like CsPbBr₃ and FAPbI₃ (FA = formamidinium), indicating its versatility in regulating the surfaces of various Pe-QDs. This work may afford new guidelines to construct electrically conductive and structurally intact Pe-QD solids for efficient optoelectronic devices.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NSFC); National Key Research and Development Program of China
• Grant/Contract Number: AC36-08GO28308; 2016YFA0202402; 2017YFA0205002; 1761145013; 61911530158; 51803144; 61674111; DE‐AC36‐08GO28308
• OSTI ID: 1660019
• Alternate ID(s): OSTI ID: 1630671
• Report Number(s): NREL/JA-5900-76409; MainId:5989; UUID:160935d5-fc69-ea11-9c31-ac162d87dfe5; MainAdminID:13778
• Journal Information: Advanced Materials, Vol. 32, Issue 26; ISSN 0935-9648
• Publisher: WileyCopyright Statement
• Country of Publication: United States
• Language: English