Synthesis and Interfacial Properties of Optically‐Active Photonic Nanocomposites with Single Nanoparticle Dispersion at High Solids Loading

The integration of inorganic rare earth doped nanoparticles in polymer matrices to obtain transparent polymer composites has attracted much attention in optical applications as the polymer‐based systems harness the benefits of both inorganic and polymer materials. To obtain highly emissive nanocomposites, it is highly desirable to maximize the loading of nanoparticles in the polymer matrices while minimizing scattering losses. This work develops a nanocomposite with brightly infrared‐emitting NaYF₄:Yb,Er nanoparticles dispersed in hydrolyzed polyhedral oligomeric silsesquioxane‐graft‐poly (methyl methacrylate) (H‐POSS‐PMMA) matrix, which is prepared by spin coating. In this process, H‐POSS‐PMMA acts as both surfactant and polymer matrix. The resulting nanocomposite exhibits mostly single nanoparticle dispersion at a high solid loading of 10 vol%, excellent thermal stability, and superior optical properties. Moreover, the H‐POSS‐PMMA modifies the particle interfacial behavior to improve colloidal stability in anisole for approximately two months. Our modification method can also be extended to other optical inorganic nanoparticles and polymer matrices, leading to significant advancements in various commercial applications such as flexible optoelectronic devices, photovoltaics, and photodetectors.