Spectral and kinetic characterization of CaS:Pr3+ phosphor synthesized through chemical co-precipitation route and post annealing process

Synthesis of Pr3+ doped CaS phosphor has been reported through chemical co-precipitation route and post annealing in the presence of NaCl, KCl and NH4Cl flux. Good crystallinity and cubic CaS phase is achieved after post-precipitation calcinations of powder at 900 °C for 1 h duration. Pseudo-spherical morphostructural features of micron-size particles are observed for phosphor prepared via chemical route. Phosphor samples are also prepared via solid-state carbothermal reduction technique for comparative studies and exhibit dendrite like structures. Prominent excitation bands at 276, 320 nm are observed for the present phosphor samples. The emission spectra show a duo-band feature at 495 and 580 nm where a spectral overlap of host lattice emission due to intrinsic defects and characteristic spectral features of Pr ion due to 3P0–1H4, 3P1–1H5, 1D2–3H4 and 3P0–3F2 transitions can be observed. The carbothermal route synthesized CaS:Pr shows spectral features of Pr ion due to 3P0–1H4 and 3P0–3Fj transitions. Electron spin resonance investigations reveal the presence of unintentional Mn2+ through a sextet signature. F+ electron trapping center is detected having g = 2.0034. Thermoluminescence glow curves possess a broad duo-band feature between room temperature −100 °C and >125 °C under host UV irradiation. Kinetic characterization using glow curve deconvolution reveals quasicontinuous distribution of traps having energy between 0.56 and 1.15 eV and frequency factors between 107 and 1011/sec.