<p>The incorporation of up-conversion nanoparticles (UCNPs) into up-conversion ionogels (UCIs) can significantly influence their mechanical, flame-retardant, and photoelectric properties. To prevent the aggregation of UCNPs after cessation of physical conditions such as stirring or ultrasonication, pre-chemical modification is effective, but it is often time-consuming and cumbersome. There is still a great challenge in maintaining a well-dispersed state of UCNPs without physical mixing or pre-chemical modification. Herein, in a precursor solution of hydroxyethyl acrylate (HEA)/ionic liquid/UCNPs, photopolymerization was applied to achieve uniform dispersion of UCNPs in the ionogel by fragmenting nanoparticle clusters. The mechanism of in situ photopolymerization-induced nanoparticle dispersion was elucidated with the aid of molecular dynamics simulations of the reaction process. Furthermore, the performance of photo-cured UCIs as a coating layer for solar panels revealed that UCNPs exhibited superior up-conversion efficiency, compared to that of the physically dispersed system without photopolymerization. Notably, solar panels with a UCI layer displayed a 33% enhancement in photoelectric conversion efficiency at a nanoparticle loading of only 0.5&#xa0;wt%.</p> Graphical abstract <p>Photopolymerization is utilized to induce the dispersion of up-conversion nanoparticles (UCNPs) in up-conversion ionogel (UCI) that efficiently improves the photoconversion efficiency (PCE) of the solar panel.</p>