Light-Induced Photoluminescence Quenching and Degradation in Quasi 2D Perovskites Film of (C6H5C2H4NH3)2 (CH3NH3)2[Pb3I10]

Quasi-two-dimensional (2D) perovskites recently came into the focus because of their moisture stability. In addition to ambient air, light illumination could also cause degradation for the film of 2D perovskites; however, few studies have investigated their photostability. Here, we work on light-induced photoluminescence quenching, as well as the degradation of quasi-2D perovskites of PEA2MAn−1PbnI3n+1 (n = 3 nominally, PEA+ = C6H5(CH2)2NH3+, MA+ = CH3NH3+). Light-induced photoluminescence (PL) quenching generally happens with different speeds, depending on the wavelength and intensity of the laser as well as the film’s environment. With red light (635 nm) illumination, the film does not decompose into ambient air with an intensity below ~500 mW/cm2, although in general, a higher laser intensity and/or higher photon energy (447 nm) could render the decomposition process easier and faster. On the other hand, when the film is in a vacuum, both light-induced PL quenching and film degradation are significantly suppressed. Furthermore, we find that the multiphase of n = 1, 2, 3 in the PEA2MA2Pb3I10 film decomposes together and that the degradation processes begin with the collapses of the crystalline structures.