CsPbBr3/Porous‐SiO2 Composite Film for Efficient Perovskite Light‐Emitting Diodes

Abstract This study aims to enhance the performance of inorganic perovskite light‐emitting diodes (PeLEDs) by incorporating porous silica (p‐SiO2) to fabricate perovskite‐composite films for electroluminescence (EL) devices. This is because, in addition to the inorganic perovskite material, composites with inherently stable materials are needed for perovskite to ensure additional external stability. The introduced p‐SiO2 particles impede the crystal growth of perovskite during the anti‐solvent assisted crystallization process, resulting in the formation of smaller CsPbBr3 crystals in the CsPbBr3/p‐SiO2 composite film. Accordingly, compared to previous CsPbBr3 films, this composite film exhibits two folds with higher photoluminescence quantum yield (PLQY) due to improved crystalline formation. Surprisingly, the CsPbBr3/p‐SiO2 composite film additionally has good water‐resistant properties because the residual cetyltrimethylammonium bromide (CTAB) molecules are extracted from the p‐SiO2 particles and are oriented at the top surface of the CsPbBr3/p‐SiO2 composite film. The EL device fabricated with this composite film exhibits outstanding luminescence efficiency, with a current efficiency (CE) of 70.06 cd A−1 and an external quantum efficiency (EQE) of 16.97%, surpassing control samples by two folds of magnitude. Furthermore, the operational stability improves approximately sevenfold compared to the control, presenting a promising strategy for advancing the field of inorganic perovskite ELs.