Reaction-Driven Self-Organization of Nanocrystals by Kinetic Control of Inhomogeneous Photopolymerization.

Reaction-driven self-organization of nanocrystals offers a promising route to functional patterns, yet the kinetic principles governing this process remain poorly understood. Here, we investigate how CsPbBr3 perovskite quantum dots (PQDs) migrate and spontaneously organize under patterned-light-induced photopolymerization. Using a custom-built digital micromirror device-based light projection system combined with in situ confocal microscopy, we directly correlate the applied light field with nanocrystal transport. We show that PQD migration is driven by the time-dependent generation of a monomer-conversion difference between high- and low-light-intensity regions, but that the final pattern is not determined by this driving force alone. Under weak irradiation, redistribution of other mobile species relaxes the conversion difference, whereas under strong irradiation, rapid polymerization is inferred to reduce PQD mobility through viscosity buildup and solidification. Intermittent and periodic irradiation reveal that nanocrystal self-organization is governed by a competition between buildup of the driving force and loss of mobility during solidification. These results establish a kinetic design principle for reaction-driven nanocrystal patterning and show that photopolymerization can serve as a programmable reaction-diffusion field for directing colloidal transport and self-organization.