Tailoring the Optical Properties of Selenium Nanoneedles by Pulsed Laser Ablation in Liquids: Implications for Solar Cells and Photocells

Selenium is a key chemical element used in photovoltaics and energy storage. It has been classified as an energy-critical element by the American Physical Society and the Materials Research Society. As selenium is crucial to develop energetic applications, various techniques have been used to synthesize selenium nanostructures such as wet chemistry, vapor-phase growth, and pulsed laser ablation. Here, for the first time, the nanoneedle morphology is synthesized by a technique different from e-beam lithography. To achieve this, pulsed laser ablation of a bulk selenium target was performed in various organic solvents and irradiated by a nanosecond Nd: YAG laser in the kHz regime for 5 min. The repetition rate of the pulsed laser allows one to tune the aspect ratio, sharpness, and diameter of the nanoneedle. This morphology is suitable for solar cells and photocells in optoelectronics.