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 language | American English |
---|---|
Article number | 2001906 |
Number of pages | 9 |
Journal | Advanced Materials |
Volume | 32 |
Issue number | 26 |
DOIs | |
State | Published - 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