Dynamical stability and multifunctional properties of Ni2+/Pr3+ co-doped CsPbCl3 perovskite: insights from first-principles lattice dynamics and carrier transport

TL;DR

This study uses first-principles calculations to show that Ni2+/Pr3+ co-doping stabilizes CsPbCl3 perovskite, enhances its optoelectronic properties, and reduces defect levels, making it more suitable for applications.

Contribution

It provides detailed insights into how Ni2+/Pr3+ co-doping improves stability and optoelectronic performance of CsPbCl3 perovskite through lattice stabilization and defect passivation.

Findings

Co-doping stabilizes the lattice and raises vacancy formation energies.

Phonon dispersion confirms dynamic stability of co-doped CsPbCl3.

Co-doping reduces defect levels and improves carrier mobility.

Abstract

All inorganic halide perovskites offer promising optoelectronic properties at low cost, but their structural softness and thermal instability limit applications. Density functional theory using the FP-LAPW method (WIEN2k) was used to study Ni2+/Pr3+ co-doping in CsPbCl3. Results show Ni2+ substitutes for Pb2+ at the B-site and Pr3+ for Cs at the A-site, keeping charge balance. Co-doping stabilizes the lattice, raises formation energies of halogen and metal vacancies, and reduces deep defect levels in the band gap. Phonon dispersion confirms that both pristine and co-doped CsPbCl3 are dynamically stable. Ni2+/Pr3+ co-doping suppresses low-energy vibrations and causes mode splitting in the 3 to 5 THz range, increasing phonon scattering and lowering lattice thermal conductivity. Mechanical analysis reveals higher elastic constants and bulk modulus, while ductility remains unchanged. Electronic structure calculations reveal Ni-3d and Pr-4f states at the band edges, reducing effective carrier mass and passivating vacancy states. Optical absorption is red-shifted, and the high-frequency ({\epsilon} = 2.4) and low-frequency ({\epsilon} = 7.4) dielectric constants are distinct. Transport analysis finds higher carrier mobility due to lighter effective masses. Altogether, Ni2+/Pr3+ co-doping reduces defect concentrations and improves the optoelectronic properties of CsPbCl3.