One-Pot and Template-Free Fabrication of ZnS·(ethylenediamine)_0.5 Hybrid Nanobelts

A template-free and one-pot solvothermal process has been developed for the facile synthesis of ZnS·(en)_0.5 (en = ethylenediamine) hybrid nanobelts having diverse length-to-width (aspect) ratios. While typical hybrid nanobelts synthesized at 180 °C for 6 h have an average width of 130 nm, a mean thickness of 55 nm, and an average length of 16 μm, their aspect ratios have been varied by adjusting solvent volume ratios of hydrazine monohydrate (hm) to en. A sufficient amount of sulfide from the reduction of sulfur by hm has been found to be essential for the efficient anisotropic one-dimensional growth of highly crystalline ZnS·(en)_0.5 hybrid nanobelts. The photoluminescence spectra of ZnS·(en)_0.5 hybrid nanostructures exhibit three bands located at 327, 415–430, and 587–654 nm, which are assigned to band-edge emission, trap sites-related emission, and anion-vacancy emission, respectively. The mean lifetime of photoluminescence having three decay components of 30, 170, and 2700 ps decreases with the volume ratio of hm to en due to the decrease of defect sites with the increase of the aspect ratios of ZnS·(en)_0.5 hybrid nanobelts. Compared with bare-ZnS nanobelts prepared by the hydrothermal treatment of ZnS·(en)_0.5 hybrid nanobelts, hybrid ones have shown enhanced optical properties that would give them potential for optoelectronic devices.