Light patterning semiconductor nanoparticles by modulating surface charges
Xiaoli He, Hongri Gu, Yanmei Ma, Yuhang Cai, Huaide Jiang, Yi Zhang, Hanhan Xie, Ming Yang, Xinjian Fan, Guo Liang, Zhan Yang, Chengzhi Hu
Abstract
Optical patterning of colloidal particles is a scalable and cost-effective approach for creating multiscale functional structures. Existing methods often use high-intensity light sources and customized optical setups, making them less feasible for large-scale microfabrication processes. Here, we report an optical patterning method for semiconductor nanoparticles by light-triggered modulation of their surface charge. Rather than using light as the primary energy source, this method utilizes UV-induced cleavage of surface ligands to modify surface charges, thereby facilitating the self-assembly of nanoparticles on a charged substrate via electrostatic interactions. By using citrate-treated ZnO nanoparticles, uniform ZnO patterns with variable thicknesses can be achieved. These multilayered ZnO patterns are fabricated into a UV detector with an on/off ratio exceeding 104. Our results demonstrate a simple yet effective way to pattern semiconductor nanoparticles, facilitating the large-scale integration of functional nanomaterials into emerging flexible and robotic microdevices. The integration of colloidal nanoparticles into microdevices is essential for several advanced technologies. Here, the authors have developed a scalable method of UV-triggered surface charge modulation for the rapid surface patterning with semiconductor nanoparticles.