Plasmon assisted intense blue–green emission from ZnO/ZnS nanocrystallites

Excellent luminescence properties of ZnO/ZnS nanocrystallites prepared using simple wet chemical approach at room temperature have been reported. ZnS coating on the surface of ZnO nanocrystallites enhanced the green emission (around 500 nm) by a factor of 2. The intensity of the blue emission around 450 nm of ZnO/ZnS nanocrystallites is observed to be as high as three times the emission intensity of pure ZnO nanocrystallites. A further overall increase by a factor of ∼2.5 has also been observed in the intensity of wide blue–green emission when the sample was prepared onto grating compared to that of the samples prepared onto uncoated as well as gold coated quartz. The enhanced emission is thought to be due to plasmon assisted electromagnetic field enhancement near nanocrystallites-metal interface. This is supported by power dependent photoluminescence measurements. The strong enhanced blue–green emission covering a wide spectral range of ∼375–650 nm signifies potential optoelectronic applications in near UV and VIS wavelength regimes.

► ZnO/ZnS is an important optoelectronic materials in the blue–green spectral range.
► Strong emission and broad band coverage.
► Materials growth through simple wet-chemical approach at room temperature.
► Plasmon assisted emission enhancement.
► Non saturation behavior observed from power dependent emission studies of plasmonic sample.