Co²⁺ Doped SrZn₂(PO₄)₂ Nanophosphor for White Light Emitting Applications

Co²⁺ doped strontium zinc phosphate (SZP) nanophosphor is prepared by solution combustion method. The synthesized nanophosphor is studied by structural and spectral characterizations XRD, SEM with EDS, FT-IR, Optical absorption, EPR and Photoluminescence. X-ray diffraction pattern confirmed a monoclinic crystal phase with a crystallite size of 57 nm with the help of Debye Scherrer’s formula. Morphological investigations indicate nanoflakes structure with average particle size determined in the nano range. EDS spectrum showed the existence of Strontium (Sr), Zinc (Zn), Phosphorus (P), Oxygen (O) and Cobalt (Co) in the synthesized sample. FTIR spectrum exhibited different vibrational bands corresponding to PO₄³⁻, P-O-P and other modes. Crystal field and inter-electron repulsion parameters are evaluated as Dq = 980, B = 920 and C = 3900 cm⁻¹. Comparing optical and EPR spectra confirms the inclusion of Co²⁺ ions in octahedral site geometry and covalent nature coupling with its host lattice. The evaluated photometric parameters such as CIE coordinates and Colour Correlated Temperature (CCT) values indicate that prepared Co²⁺ doped SZP nanophosphor is potentially good for white light emitting diodes and solid state lightening.