Synthesis of perovskite nanocrystal films with a high luminous efficiency and an enhanced stability

Solid-state CsPbBr3-based perovskite nanocrystal (PNC) films with a high photoluminescence quantum yield (PLQY) and an enhanced stability were synthesized using a convenient centrifugal casting method combined with silica encapsulation and Na-doping techniques. The optical properties, composition features, surface morphology and stability of the PNC films were investigated in detail. By utilizing this centrifugation method, CsPbBr3@SiO2 PNC films with an extraordinarily uniform surface were obtained with a high PLQY of 58.0%. Furthermore, the PLQY of CsPbBr3@Na@SiO2 PNC films was improved to a large value of 74.7% after Na+-ion doping of PNCs encapsulated with silica. At the same time, both the CsPbBr3@SiO2 and CsPbBr3@Na@SiO2 PNC films, especially the latter, showed substantially improved material stability against heat, ultraviolet (UV) light and environmental conditions. LED devices fabricated using the obtained PNC films exhibited excellent optical and color properties, demonstrating the great application potential for solid-state PNC films prepared here in the light-emitting and display fields.