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Title: Elucidating the Role of a Tetrafluoroborate-Based Ionic Liquid at the n-Type Oxide/Perovskite Interface

Journal Article · · Advanced Energy Materials

Halide perovskites are currently one of the most heavily researched emerging photovoltaic materials. Despite achieving remarkable power conversion efficiencies, perovskite solar cells have not yet achieved their full potential, with the interfaces between the perovskite and the charge-selective layers being where most recombination losses occur. In this study, a fluorinated ionic liquid (IL) is employed to modify the perovskite/SnO2 interface. Using Kelvin probe and photoelectron spectroscopy measurements, it is shown that depositing the perovskite onto an IL-treated substrate results in the crystallization of a perovskite film which has a more n-type character, evidenced by a decrease of the work function and a shift of the Fermi level toward the conduction band. Photoluminescence spectroscopy and time-resolved microwave conductivity are used to investigate the optoelectronic properties of the perovskite grown on neat and IL-modified surfaces and it is found that the modified substrate yields a perovskite film which exhibits an order of magnitude lower trap density than the control. When incorporated into solar cells, we report this interface modification results in a reduction in the current-voltage hysteresis and an improvement in device performance, with the best performing devices achieving steady-state PCEs exceeding 20%.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
Engineering and Physical Sciences Research Council (EPSRC); European Commission (EC); USDOE; National Science Foundation (NSF)
Grant/Contract Number:
AC36-08GO28308; 06552-APPEL; DMR-1420541; AC36‐08GO28308
OSTI ID:
1593690
Alternate ID(s):
OSTI ID: 1579264
Report Number(s):
NREL/JA-5900-74791
Journal Information:
Advanced Energy Materials, Vol. 10, Issue 4; ISSN 1614-6832
Publisher:
WileyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 73 works
Citation information provided by
Web of Science

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