Modifying the optical emission of two-dimensional Ruddlesden-Popper perovskites by laser irradiation

Abstract

Two-dimensional (2D) organic–inorganic hybrid perovskites, especially Ruddlesden-Popper (RP) perovskites, have attracted great interest in recent years due to their potential applications in the fields of optoelectronics and photovoltaics. In this work, the effects of laser irradiation on the optical emission of a PEA2MA2Pb3I10 thin film (PTF) were systematically investigated by using 488-nm continuous wave laser light and 400-nm femtosecond laser light as the excitation sources. It was found that the photoluminescence (PL) intensity of a PTF increases rapidly with irradiation time and becomes saturated after some time, which is ascribed to the passivation of the defects near the surface of the PTF through the interaction with oxygen. A large redshift of the PL wavelength from ∼ 625 to ∼ 750 nm was realized by simply increasing the laser power. It was suggested that the decomposition of PEA2MA2Pb3I10 into MAPbI3 is responsible for this behavior. The excitation efficiency was improved while the threshold laser power for the decomposition was lowered by constructing a particle-on-film system with a silica microsphere. In this way, the blueshift of the PL wavelength from ∼ 750 to ∼ 520 nm, which is attributed to the further decomposition of MAPbI3 into PbI2, was achieved. Our findings provide a simple and effective way for modifying the optical emission of 2D perovskites and pave the way for realizing photonic devices based on 2D perovskites.