Composition Variation and Thermal Treatment of Zn x Cd 1− x S Alloy Nanoparticles to Exhibit Controlled and Efficient Luminescence

Zn x Cd 1− x S (0 ≤ x ≤ 1) alloy nanoparticles have been fabricated facilely using ethylenediamine as a solvent-coordinating molecular template in water. Zn x Cd 1− x S ( 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 Zn x Cd 1− x S alloy nanoparticles shifts largely to the blue with the composition increase of Zn to have the shortest wavelength at x = 0.9 (λ max = 480 nm for CdS, 396 nm for Zn 0.9 Cd 0.1 S, 424 nm for ZnS). The thermal treatment of as-prepared Zn x Cd 1− x S 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.