Bright and Stable Luminescence of CsPbX3 Nanocrystals in ZrO2 Skeletons for White Light Emitting Diodes

Abstract

Inorganic perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) have been recognized as ideal luminescent materials for display fields owing to their superior optical and electronic properties. However, the poor stability of NCs seriously restricts practical applications. In this paper, CsPbX3 NCs with different emitting colors from blue to red were encapsulated in ZrO2 skeletons in situ using a hot injection method to overcome poor stability. The CsPbX3 NCs were well dispersed in ZrO2 skeletons, in which the photoluminescence (PL) properties were improved. On the one hand, the NCs with brighter PL, higher stability, and narrower PL spectrum were obtained by in situ growth. On the other hand, these perovskite NCs were embedded in white powder ZrO2, effectively preventing its deterioration in wet and light conditions. The fluorescence of the composites was regulated by controlling the proportion of halogen ions in the CsPbX3@ZrO2 composite. A flexible thin film with bright luminescence and high stability was prepared. Furthermore, CsPbX3@ZrO2 composites were applied to make simple light emitting diodes (LEDs). White LEDs were fabricated by using blue-emitting CsPb(Cl/Br)3@ZrO2, green-emitting CsPbBr3@ZrO2, and red-emitting CsPb(Br/I)3@ZrO2 composites. The Commission Internationale de I’Eclairage color coordinates of the white LEDs were (0.31, 0.33) and are within the white light range. This work provides an effective strategy for binding perovskite NCs to inorganic substrates for luminescent display fields.