Spectral and surface investigations on SrZnO2:Tb3+ nanophosphors

Abstract

SrZnO₂: Tb³⁺ nanophosphor was synthesized through a combustion process using metal nitrates as precursors and urea as fuel. The nanocrystals have sizes ranging from 25 nm to 30 nm. X-Ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) and cathodoluminescence (CL) spectra were utilized to characterize the present samples. Under UV excitation, it shows several bands centered at 487, 544, 588 and 624 nm, which result from ⁵D₄→⁷F_J (J = 6, 5, 4 and 3) transitions of Tb³⁺, and the green emission band (⁵D₄→⁷F₅) located at 544 nm is dominant. X-ray Photoelectron Spectroscopy (XPS) technique was used to study oxygen related defects and the surface chemical composition. Surface chemical study suggests that oxygen vacancies may be generated by surface shrinkage due to the size reduction. A surface sensitive analytical technique namely time of flight-secondary ion mass spectroscopy (TOF-SIMS), respectively was used for imaging which shows an uniform distribution of  Tb³⁺ in the SrZnO₂.