(ZnS)x(Cu0.1InS1.55) heteronanocrystals with broadband emission as a single component for potential WLEDs

Semiconductor nanocrystals as a single component for fabricating WLEDs have proven to be a simple and effective alternative. In this paper, (ZnS)x(Cu0.1InS1.55) heteronanocrystals (HNCs) were easily synthesized via a hot injection route using a mixture of ethylxanthate salts as precursors. The as-prepared heteronanocrystals were characterized by X-ray diffraction, transmission electron microscopy, UV-Vis absorption and photoluminescence spectroscopies. The effects of the Zn mole fraction on the crystal structure and optical properties were studied. The absorption of the HNCs shifts to shorter wavelengths with increasing the Zn component. The photoluminescence (PL) spectra with the two broad emissions of blue (about 435 nm) and yellow-red (590-643 nm) were observed and assigned to the corresponding transition pathways. Their peculiar luminescence with high efficiency shows a quite tunable emission from cool to warm by varying the mole ratios of Zn precursor. The single component based WLED with optical conversion was simply fabricated by coating (ZnS)0.4(Cu0.1InS1.55) HNCs onto a commercial UV-LED. The operation time under UV excitation is derived to be around 4.5 h.