Abstract
We have synthesized Bi doped SrS nanophosphors using solid state diffusion method. Since Bi3+ is expected to replace Sr2+, therefore sodium thiosulphate was used as charge compensator during synthesis process. The X-ray diffraction pattern confirms the single phase cubic structure of SrS without any secondary phases pertaining to the dopant. The average crystallite size estimation from XRD peaks confirms the formation of nanophosphors. The SrS: Bi nanophosphors show a broad photoluminescence emission spectra centred at 494 nm at an excitation wavelength of 414 nm, which has been identified as P-3(1) to S-1(0) transitions of Bi3+. The band at 414 nm in excitation spectrum, which was recorded at an emission wavelength of 494nm, has been assigned to corresponding absorption transitions. Another band at 350 nm in the excitation spectrum has also been observed which may be assigned to the overlap of transitions from the ground state to P-3(2) and P-1(1). We investigated the effect of different excitation wavelengths on the photoluminescence spectra of SrS: Bi nanophosphors. The highly efficient blue-green emission of SrS: Bi may be utilized in many practical phosphor based applications.