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

Xufeng Ling, Jianyu Yuan, Xuliang Zhang, Yuli Qian, Shaik Zakeeruddin, Bryon Larson, Qian Zhao, Junwei Shi, Jiacheng Yang, Kang Ji, Yannan Zhang, Yongjie Wang, Chunyang Zhang, Steffen Duhm, Joseph Luther, Michael Gratzel, Wanli Ma

Research output: Contribution to journalArticlepeer-review

130 Scopus Citations

Abstract

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.

Original languageAmerican English
Article number2001906
Number of pages9
JournalAdvanced Materials
Volume32
Issue number26
DOIs
StatePublished - 2020

Bibliographical note

Publisher Copyright:
© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

NREL Publication Number

  • NREL/JA-5900-76409

Keywords

  • CsPbI
  • guanidinium thiocyanate
  • ligand exchange
  • perovskite quantum dots
  • solar cells

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