Infrared to visible conversion in strontium sulphate through defect-based IR stimulated visible emission phenomenon.

Strontium sulphate (SrSO 4 ) is a defect-based photoluminescence material, generally used in thermoluminescence application, has been studied for IR stimulated visible emission. The SrSO 4 particles were synthesized by precipitation method. The orthorhombic phase of SrSO 4 is confirmed from XRD pattern and formation of micron-sized particles is authenticated from Field Emission Scanning electron micrographs (FESEM). The elemental composition of oxygen and strontium is determined using Energy Dispersive X-ray analysis (EDAX) measurement which confirms the presence of V O • • and V Sr ' ' intrinsic defects in the material. Photoluminescence investigations show the presence of various defect bands in the band gap giving rise to intrinsic luminescence in SrSO 4 . The emission in visible region attributes to the defect band arising due to V O • • . PL lifetime measurement confirms the presence of stable defect states having lifetime in microseconds. SrSO 4 sample was tested using IR lasers and a red-orange emission spot was observed from the powder sample when excited with IR lasers. The underlying principle for IR to visible conversion in the material is a defect mediated phenomenon which has been described through the energy level diagram of the material.