Analysis on the defect states of FA<sub>x</sub>MA<sub>1-x</sub>PbI<sub>3</sub> perovskite single crystals grown by inverse-temperature crystallization

Abstract

The FA(0.6)MA(0.4)PbI(3), FA(0.8)MA(0.2)PbI(3) and FAPbI(3) perovskite single crystals were prepared by the inverse temperature crystallization method. From the deep level transient spectroscopy (DLTS) measurement and optical conduction DLTS, the FA(0.6)MA(0.4)PbI(3) and FA(0.8)MA(0.2)PbI(3) samples had the majority carrier defects of E2 and E3 with E-a of 0.52 and 0.59 eV, which were positioned below the conduction band minimum, and the FAPbI(3) sample had the minority carrier defect of H2 with E-a of 0.60 eV above the valence band maximum. The origin of the defect states of E2, E3 and H2 are related to FA-I antisite defects, Pb interstitial defects and iodine vacancy, respectively. Among the samples, the defect density (N-t) of H2 on FAPbI(3) was lower than that of any other sample, although the normalized integrated photoluminescence intensity of the FA(0.8)MA(0.2)PbI(3) sample was higher than that of any other sample. This is due to the fact that H2 was a minority carrier defect and E2 and E3 were majority carrier defects.