Structure, photoluminescence, and electrical transport properties of pure and Eu2O3 activated Zn2SnO4 host matrix

Abstract In this work, crystalline Eu2O3 activated Zn2SnO4 nanoparticles were synthesized with a simple mechanosynthesis method followed by a post-heat-treatment process. Pure Zn2SnO4 (ZTO) and Eu: ZTO samples were synthesized following the same method for a comparative study. The structure and microstructure of these compounds have been characterized in detail by the Rietveld refinement method using powder XRD data and analyzing FESEM and HRTEM images. The formation of a nanocrystalline cubic Eu2Sn2O7 secondary phase is noticed in the Eu-activated compound. The influence of Eu3+ cations in the ZTO host matrix is revealed from the photoluminescence and electrical transport studies. The Eu3+ ions generate oxygen vacancy by substituting octahedral Sn4+/Zn2+ ions of the ZTO inverse spinel lattice rather than tetrahedral Zn2+ ions. It initiates optical luminescence with several intense emissions between 576 nm and 711 nm with narrowband electric dipole emissions of Eu3+ ions. The influence of oxygen vacancies on the atomic structures of the Eu:ZTO compound was revealed by the electrical transport studies and compared to pure ZTO. It is revealed that the electrical conductivity increases due to the oxygen vacancy originated by Eu3+ incorporation into the ZTO lattice. Due to superior optical property, enhanced electrical conductivity, and low dielectric constant value, the Eu:ZTO compound is appropriate for superior optoelectronic applications.