An insight into indium effect on the crystal structure and thermoluminescence of LiMgPO4: Combined experiment and ab initio calculations

In this work, indium doped LiMgPO4 is first considered as a dosimetric material. We present studies of the structural properties and thermally stimulated luminescence (TSL), as well as electronic structure of pure and indium doped LiMgPO4. We observed a nonmonotonic shift in the TSL peak with increasing indium concentration (x), which was associated with two different indium sites. We demonstrated that In3+ predominantly replaces Mg2+, but at indium concentration of less than 1%, it occupies the Li+ positions. The variation in indium substitution site affects also the depth of electron traps. Doping of LiMgPO4 with indium changes not only the TSL glow curves, but also the spectra of thermoluminescence. The spectrum of undoped LiMgPO4 consists of two broad bands located in the UV region (λ = 350 nm) and in the red region (λ = 640 nm), while there is only one line (λ = 630 nm) in the TSL spectra of LiMgPO4:In3+. The mechanism of thermoluminescence in pure and indium doped LiMgPO4 is discussed. [Display omitted] •The position of TSL peak depends on the indium concentration in LiMgPO4: In.•In3+ replaces Li + at x < 1%, but Mg2+ at a higher indium concentration.•The depth of electron traps depends on the indium site.•The TSL spectrum of LiMgPO4 consists of red and UV wide bands.•Indium eliminates oxygen vacancies in LiMgPO4 and dampens the UV part of TSL.