Composition Variation and Thermal Treatment of ZnxCd1−xS Alloy Nanoparticles to Exhibit Controlled and Efficient Luminescence

Abstract

ZnxCd1−xS (0 ≤ x ≤ 1) alloy nanoparticles have been fabricated facilely using ethylenediamine as a solvent-coordinating molecular template in water. ZnxCd1−xS (x = 0.5) alloy nanoparticles of single-crystalline wurtzite structures having no staking faults have been constructed homogeneously to show that they are intermediate between ZnS and CdS in d-spacing and 2θ values. The photoluminescence of ZnxCd1−xS alloy nanoparticles shifts largely to the blue with the composition increase of Zn to have the shortest wavelength at x = 0.9 (λmax = 480 nm for CdS, 396 nm for Zn0.9Cd0.1S, 424 nm for ZnS). The thermal treatment of as-prepared ZnxCd1−xS alloy nanoparticles at 120 °C for 10 h has been found to increase photoluminescence intensity and lifetime by a factor of 5. This increase has been attributed to the decomposition of coordinated water molecules during annealing processes.