%0 Journal Article
%T Deep Defect States in Wide-Band-Gap ABX3 Halide Perovskites
%J -
%D 2019
%R https://doi.org/10.1021/acsenergylett.9b00709
%X Lead bromide-based halide perovskites are of interest for wide-band-gap (>1.75 eV) absorbers for low-cost solar spectrum splitting to boost solar-to-electrical energy conversion efficiency/area by adding them to c-Si or Cu(In,Ga)Se2 PV cells and for photoelectrochemical solar fuel synthesis. Deep in-gap electronic states in PV absorbers serve as recombination centers and are detrimental for the cell¡¯s photovoltaic performance, especially for the open-circuit voltage (Voc). We find four different deep defect states in polycrystalline layers of mixed-cation lead tribromide from high-sensitivity modulated surface photovoltage (SPV) spectroscopy. Measurements were performed with different contact configurations, on complete solar cells and on samples before and after aging or stressing at 85 ¡ãC under illumination. Three of the four states, with energies of ¡«0.63, 0.73, and 1.35 eV below the conduction band edge, are assigned to intrinsic defects, whereas defect states in the middle of the band gap could be associated with (uncontrolled) impurities
%U https://pubs.acs.org/doi/10.1021/acsenergylett.9b00709