Optothermal-Enabled Reconfigurable Colloidal Photonic Crystals for Color and Spectrum Manipulation

Colloidal photonic crystals (CPCs) are extensively utilized in nanoscale light manipulation due to their periodic dielectric structure. However, achieving spatial reconfigurability in CPCs remains a significant challenge, despite its importance for broader photonic applications in colloidal science. In this study, an optically induced thermoelectric field is generated by adding ionic surfactants to the solution, leading to the efficient formation of tightly assembled nanoparticles that exhibit the characteristics of CPC, which is termed optothermo-CPC. Specifically, this CPC exhibits excellent spatial reconfigurability through the tuning of the optically induced thermoelectric field. This allows for the remote control of its position and shape, in a real-time and high-precision manner. Additionally, by changing the particle size, it is possible to tune the transmission spectrum and color. Additionally, optothermo-CPC can navigate obstacles and possess a robust self-healing ability. These highly adaptable and reconfigurable properties endow CPCs with significant potential for various photonic applications within complex fluidic environments.