Large shift in the photoluminescent properties of Mn2+ -doped nanosized CdS–ZnS solid solutions

Crystal field dependence of Mn2+ (4T1→6A1) emission shows a large shift (∼100 nm) in the Photoluminescent features, sensitive to either Zn or Cd rich, solid solutions of CdS–ZnS prepared via a novel microwave-assisted synthesis. Cd2+ excess composition viz., Cd0.54Zn0.45Mn0.01S shows a structured emission between 380 and 500 nm, while a Zn2+ excess composition such as Cd0.48Zn0.51Mn0.01S shows a red-shifted featureless broad emission at 505 nm (with FWHM ∼80 nm). The emission features of the Cd2+ excess composition occur from trap levels and quantized midgap states arising from ZnS–CdS bandgap. For a marginal increase in Mn concentration from 1% to 2%, a substantial broadening in emission leading to white light is observed in relatively Zn deficient solid solution.