Spectral and surface investigations of Mn2+ doped SrZnO2 nanocrystalline phosphors

A yellow light-emitting SrZnO2:Mn2+ nanophosphor was synthesized through a combustion process using metal nitrates as precursors and urea as fuel. The nanocrystals have sizes ranging from 25 to 30 nm. X-ray diffraction, transmission electron microscopy, photoluminescence (PL) and cathodoluminescence spectra were utilized to characterize the present samples. Crystallographically the occupancy of cations in SrZnO2 has been explained. Under the UV and the electron-beam excitation, the SrZnO2:Mn2+ nanoparticle shows a yellow emission due to the characteristic transition of the Mn2+ (4T1 → 6A1). To study oxygen-related defects and the surface chemical composition, the X-ray photoelectron spectroscopy technique was used. Surface chemical study suggests that oxygen vacancies may be generated by surface shrinkage due to the size reduction. For post-combustion annealing at 900 °C, the PL intensity of the nanopowders was increased due to better crystallinity and improved activity of the recombination centers.