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Guanidinium‐Assisted Surface Matrix Engineering for Highly Efficient Perovskite Quantum Dot Photovoltaics
Author(s) -
Ling Xufeng,
Yuan Jianyu,
Zhang Xuliang,
Qian Yuli,
Zakeeruddin Shaik M.,
Larson Bryon W.,
Zhao Qian,
Shi Junwei,
Yang Jiacheng,
Ji Kang,
Zhang Yannan,
Wang Yongjie,
Zhang Chunyang,
Duhm Steffen,
Luther Joseph M.,
Grätzel Michael,
Ma Wanli
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202001906
Subject(s) - materials science , quantum dot , formamidinium , photovoltaics , perovskite (structure) , nanotechnology , chemical engineering , photovoltaic system , ecology , engineering , biology
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 CsPbI 3 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 CsPbI 3 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 CsPbBr 3 and FAPbI 3 (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.