Boosting Photovoltaic Performance for Lead Halide Perovskites Solar Cells with BF4 Anion Substitutions

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Article number1808833
Journal / PublicationAdvanced Functional Materials
Issue number47
Online published14 Feb 2019
Publication statusPublished - 21 Nov 2019


Composition engineering is a particularly simple and effective approach especially using mixed cations and halide anions to optimize the morphology, crystallinity, and light absorption of perovskite films. However, there are very few reports on the use of anion substitutions to develop uniform and highly crystalline perovskite films with large grain size and reduced defects. Here, the first report of employing tetrafluoroborate (BF4 ) anion substitutions to improve the properties of (FA = formamidinium, MA = methylammonium (FAPbI3)0.83(MAPbBr 3)0.17) perovskite films is demonstrated. The BF4 can be successfully incorporated into a mixed-ion perovskite crystal frame, leading to lattice relaxation and a longer photoluminescence lifetime, higher recombination resistance, and 1–2 orders magnitude lower trap density in prepared perovskite films and derived solar cells. These advantages benefit the performance of perovskite solar cells (PVSCs), resulting in an improved power conversion efficiency (PCE) of 20.16% from 17.55% due to enhanced open-circuit voltage (VOC ) and fill factor. This is the highest PCE for BF4 anion substituted lead halide PVSCs reported to date. This work provides insight for further exploration of anion substitutions in perovskites to enhance the performance of PVSCs and other optoelectronic devices.

Research Area(s)

  • compositional engineering, nonradiative recombination, perovskite solar cells, tetrafluoroborate, trap density reduce