Abstract
Single-phased bright-red emitter Ca9Bi1–x(PO4)7:xEu3+ nanophosphor series was obtained by time-saving combustion-synthesis technique. The structural prototype for Ca9Bi(PO4)7 and Ca9Bi0.40(PO4)7:0.60Eu3+ were obtained by using the Rietveld refinement method, revealing a trigonal crystal system of R3c(161) space group symmetry. The values of the band-gap for maximum-fluorescent-concentration and pure host were determined to be 4.23 and 4.30 eV, respectively. The critical distance for energy migration (12.35 Å) and Dexter’s exchange-profiling held the dipole/dipole (d–d) interactions responsible for the quenching process observed after optimum composition. The refractive index of the pure host (2.22) and the photoluminescent (PL) emission spectra of Eu3+-doped samples were used to work out Judd-Ofelt intensity parameters. The detailed photo-luminescent analysis provided the value of quantum efficiency, non-radiative and total radiative transition-rate for Ca9Bi0.40(PO4)7:0.60Eu3+ phosphor. Furthermore, various optical results, including the very high value of stimulated emission-cross-section (10.64), claim Ca9Bi0.40(PO4)7:0.60Eu3+ system as a very much promising candidate for the laser and solid-state lighting (SSL) devices.