Spatially resolved photoluminescence (PL) of methylammonium lead iodide (MAPbI3) films in planar heterojunction solar cells is probed by time-resolved confocal microscopy to study the interface effect on PL intensity-voltage (PL-V) hysteresis. Negligible PL-V hysteresis is observed at the interfacial area, while significant hysteresis is observed in the bulk film. PL lifetime imaging of the perovskite device reveals inhomogeneous charge extraction due to variation of the interfacial contact quality. Poor interfacial contact leads to more severe PL-V hysteresis in the bulk perovskite film. The PL-V characteristics also suggest that voltage-driven ion migration may lead to redistribution of charge traps, and consequently affect the nonradiative charge recombination and the PL intensity in MAPbI3 films.
Bibliographical noteFunding Information:
This work was supported by the Grant-in-Aid program of the University of Minnesota. Research was carried out in part at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-SC0012704. The use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This project was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Visiting Faculty Program (VFP). The authors would like to thank Dr. Mircea Cotlet, Dr. ChangYong Nam, and Dr. Seth Darling for their technical support on solar cell fabrication and characterizations.
© 2017 Author(s).