Synthesis of t-Te and a-Se nanospheres using continuous wave visible light

We demonstrate a simple and cost-effective method for the synthesis of elemental Se and Te nanoparticles. The method employs irradiation of bulk Se and Te by visible light, continuous wave sources and results in uniform deposition of nanoparticles on various substrates. The process is fast and avoids the steps of pre- and post-treatment involved in solution-based approaches. The resulting Se and Te nanoparticles have an exclusively spherical morphology and diameters in the order of 50 and 100 nm, respectively. Spectroscopic and electron microscopy characterization reveals that Te nanospheres are single crystalline with trigonal structure and can develop an oxidized surface shell, while Se nanoparticles are identified as purely amorphous. At high-yield growth, Te nanospheres aggregate but preserve their particulate morphology while amorphous Se nanoparticles form fractal-like morphologies. The present work might be important for various areas such as biomedical applications owning to the high antibacterial activity of Te and Se nanostructures and the avoidance of hazardous chemicals.