Mechanisms for light induced degradation in MAPbI3 perovskite thin films and solar cells
- Atomic Energy Authority (AEA), Nasr City, Cairo (Egypt). Dept. of Radiation Physics, National Center for Radiation Research and Technology (NCRRT); Univ. of California, Santa Cruz, CA (United States). Dept. of Chemistry and Biochemistry
- Univ. of California, Santa Cruz, CA (United States). Dept. of Physics
- Univ. of California, Santa Cruz, CA (United States). Dept. of Chemistry and Biochemistry; Chongqing Univ., Chongqing (China). College of Chemistry and Chemical Engineering
- Univ. of California, Santa Cruz, CA (United States). Dept. of Chemistry and Biochemistry
Organometal halide perovskites are highly promising materials for photovoltaic applications, yet their rapid degradation remains a significant challenge. Here, the light-induced structural degradation mechanism of methylammonium lead iodide (MAPbI3) perovskite films and devices is studied in low humidity environment using X-Ray Diffraction, Ultraviolet-Visible (UV-Vis) absorption spectroscopy, Extended X-ray Absorption Fine Structure spectroscopy, Fourier Transform Infrared spectroscopy, and device measurements. Under dry conditions, the perovskite film degrades only in the presence of both light and oxygen, which together induce the formation of halide anions through donation of electrons to the surrounding oxygen. The halide anions generate free radicals that deprotonate the methylammonium cation and form the highly volatile CH3NH2 molecules that escape and leave pure PbI2 behind. The device findings show that changes in the local structure at the TiO2 mesoporous layer occur with light, even in the absence of oxygen, and yet such changes can be prevented by the application of UV blocking layer on the cells. Our results indicate that the stability of mp-TiO2-MAPbI3 photovoltaics can be dramatically improved with effective encapsulation that protects the device from UV light, oxygen, and moisture.
- Research Organization:
- Stanford Univ., CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
- Grant/Contract Number:
- EE0004946
- OSTI ID:
- 1465793
- Alternate ID(s):
- OSTI ID: 1334828
- Journal Information:
- Applied Physics Letters, Vol. 109, Issue 23; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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