Levine, I.; Vera, O.; Kulbak, M.; Ceratti, D.; Rehermann, C.; Márquez, J.; Levcenko, S.; Unold, T.; Hodes, G.; Balberg, I.; Cahen, D.; Dittrich, T.: Deep Defect States in Wide-Band-Gap ABX 3 Halide Perovskites. ACS Energy Letters 4 (2019), p. 1150-1157
We find 4 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°C 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 are thought to be associated with (uncontrolled) impurities.