Preparation of Rod- and Urchin-Like Selenium Nanostructures by Hot-Injection and Application to Simple Flexible Coated Photosensors

This study presents a synthetic approach for obtaining highly crystalline selenium (Se) nanorods (NRs) and urchin-like nanostructures. By modulating the postinjection cooling rate, the morphology of Se nanostructures can be precisely tuned, promoting anisotropic growth in the presence of supersaturated Se monomers. This method enables a rapid phase transformation from amorphous to trigonal Se under ambient pressure and low-temperature conditions. Furthermore, a simple, flexible light detector was fabricated via dip-coating Se nanorods onto PET, yielding an ON/OFF ratio of ≈10 and stable operation after more than 3000 bending cycles. This work demonstrates a rapid, scalable route for morphology-controlled Se nanostructures compatible with low-cost and flexible optoelectronic applications. The proposed method offers a promising strategy for producing high-quality one-dimensional (1D) nanomaterials.