Doping disorder and the reduction–doping process in LiSrPO4

Abstract

A systematic theoretical study was performed on trivalent and divalent rare-earth (RE) dopant ions in the LiSrPO₄ structure, using atomistic simulations based on lattice energy minimization. It was found that RE³⁺ and RE²⁺ ions are most energetically favorable for incorporation at the Sr site. For RE³⁺ ion incorporation, charge compensation by vacancies or anti-site defects are both probable. In order to investigate the reduction–doping process (Europium reduction), two schemes (open atmosphere and H₂ reducing atmosphere) were considered. A H₂ reduction atmosphere was found to be the most effective agent for Eu reduction. Results reveal that the most probable charge compensation mechanism and the host site preference for rare-earth doping ions play important roles in the investigation of the mechanism of the luminescence properties of LiSrPO₄.