Advances in Light-Driven Nanocrystal Assembly: From Two-Dimensional Patterning to Three-Dimensional Manufacturing.

Colloidal nanocrystals serve as a versatile platform for solution-processed electronics, optoelectronics, and photonics. While early efforts centered on two-dimensional (2D) patterned films for planar devices, increasing demands for integration density and multifunctionality are driving a transition toward three-dimensional (3D) nanocrystal architectures. Light-driven assembly has emerged as a powerful, noninvasive approach, enabling remote activation, high spatial selectivity, and broad compatibility across nanocrystal compositions and surface chemistries. Recent advances in photolithography and laser-based fabrication have bridged planar patterning and volumetric construction. Here, we present a unified framework for light-driven nanocrystal assembly based on fundamental energy-transduction pathways, including photopolymerization, photoreduction, and photoinduced interparticle coupling. We discuss how these mechanisms govern high-fidelity 2D patterning and enable emerging strategies for 3D structuring and manufacturing. Finally, we highlight key challenges and opportunities in achieving structural precision, functional integrity, multimaterial integration, and device-level implementation, and outline future directions toward programmable nanocrystal-based manufacturing.