Reinforcing effects of waterproof substrate on the photo-, thermal and pH stabilities of perovskite nanocrystals

Lead halide perovskites have generated remarkable progress in a wide variety of opto-electronic fields. However, challenging issues including water-sensitive feature, poor stability over temperature change and mechanical fragility should be circumvented to enable the practical uses of such nanocrystals. Ethylene-propylene-diene monomer (EPDM) rubber, which possesses saturated and nonpolar polymeric chain, has been extensively explored in industry due to its sealing property, low-cost, dynamic and outstanding abrasive resistance. In this study, the hybrid inorganic-organic network with covalent cross-linkages and CsPbX3 (X = Cl and Br) quantum dots has been established in EPDM rubber system via an effective and mild approach in the process of mixing reaction at room temperature. In contrast to pure perovskite dots, the peak emission intensity of CsPb(Cl0·25Br0.75)3-EPDM can be well maintained after it has been immersed into aqueous solution for 2 h. Moreover, the water-mediated treatment will control the emission color evolution from cyan (485 nm) to green (510 nm) and such process can be fully reversible during the soaking and drying cycles. In addition, the employment of such polymeric host with superior heat resistance results in significant increases in thermal stability, mechanical strength and toughness. This efficient strategy will provide a rational design of reinforcing photoluminescence for all-inorganic perovskite quantum dots in numerous applications.