Investigation on the Cu-Dopant-Induced Modulation Effect on the Optoelectronic Efficiency and the Stability of CsPbBr3 Perovskites

Abstract

This study explores the use of Cu dopant to improve the optoelectronic properties and stability of CsPbX3 perovskites for blue-light-emitting diode material. The addition of Cu causes the metal octahedron of orthorhombic CsPbBr3 to shrink, which relaxes the lattice strain from the distortion and twisting of the [PbX6] octahedron and reduces energy from Jahn–Teller effects. A crystal orbital Hamilton population (COHP) analysis reveals that the Cu-Br bond in the [CuX6] octahedron has a higher integrated projected COHP (IpCOHP), and the strong hybridization between the Cu-3d and Br-4p bond enhances the bond interaction and the whole crystalline lattice. The addition of Cu dopants in CsPbBr3 perovskites results in a stronger framework that suppresses intrinsic defects like Br vacancies, leading to enhanced photoluminescence (PL) performance. Additionally, the Cu-3d orbitals contribute to the valence band and increase the band gap, resulting in a blue shift of the luminescence from Cu-doped CsPbBr3. These findings indicate that Cu dopants significantly improve the luminescence efficiency and the stability of CsPbBr3 perovskites, making them suitable for blue light LED applications.