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Title: Effects of intrinsic and atmospherically induced defects in narrow bandgap (FASnI3)x(MAPbI3 )1-x perovskite films and solar cells

Journal Article · · Journal of Chemical Physics
DOI: https://doi.org/10.1063/1.5126867 · OSTI ID:1599337

Narrow band gap mixed tin (Sn) + lead (Pb) perovskites are vital as the bottom sub-cell absorber in high efficiency all-perovskite polycrystalline tandem solar cells. Here, we report on the impact of mixed cation composition and atmospheric exposure of perovskite films on sub-gap absorption in films and performance of solar cells based on narrow band gap mixed formamidinium (FA) + methylammonium (MA) and Sn+Pb halide perovskites, (FASnI3)x(MAPbI3)1-x. Structural and optical properties of 0.3 ≤ x ≤ 0.8 (FASnI3)x(MAPbI3)1-x perovskite thin film absorbers with band gaps ranging from 1.25 (x = 0.6) to 1.34 eV (x = 0.3) are probed with and without atmospheric exposure. Urbach energy, which quantifies the amount of sub-gap absorption, is tracked for pristine perovskite films as a function of composition, with x = 0.6 and 0.3 demonstrating the lowest and highest Urbach energies of 23 and 36 meV, respectively. Films with x = 0.5 and 0.6 compositions show less degradation upon atmospheric exposure than higher or lower Sn-content films having greater sub-gap absorption. The corresponding solar cells based on the x = 0.6 absorber show the highest device performance. Despite having a low Urbach energy, higher Sn-content solar cells show reduced device performances as the amount of degradation via oxidation is the most substantial.

Research Organization:
Univ. of Toledo, OH (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
Grant/Contract Number:
EE0008753; FOA-0000990
OSTI ID:
1599337
Alternate ID(s):
OSTI ID: 1598732
Journal Information:
Journal of Chemical Physics, Vol. 152, Issue 6; ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 21 works
Citation information provided by
Web of Science

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