Water driven photoluminescence enhancement and recovery of CH3NH3PbBr3/Silicon oil/PDMS-urea composite

Lead halide perovskites (LHPs) are very promising for new optoelectronic devices due to their excellent optical and electronic properties. However, the poor stability against water, heat and UV light greatly restricts their practical applications. In this work, a CH 3 NH 3 PbBr 3 /silicon oil/PDMS-urea composite is prepared by encapsulating CH 3 NH 3 PbBr 3 nanocrystals and silicon oil into the PDMS-urea polymer matrix . This composite shows characteristics of water-enhanced photoluminescence (PL) and water-driven PL recovery. After immersed in water, the photoluminescence quantum yield of the composite increases from initial 26.0%–52.2%, which is ascribed to the passivation of surface defects by the capping of polymer chains, H 3 O + and OH − . The composite possesses superior stability against UV light illumination in water. Furthermore, the composite film exhibits a capability of water-driven PL recovery after UV light irradiation. By applying alternate water/UV treatments, the PL can be reversibly switched “on and off”. The “on/off” ratio value of the PL intensity reached more than 4. These advantages make this composite highly promising in applications utilising luminescent switching and for under water lighting.