Enhanced Green Photoluminescence of QDs in Color-Conversion Metasurfaces via Nanoimprinted High-Index Ultrathin Layers

Quantum dots (QDs) serve as efficient color-conversion materials in display technologies owing to their high quantum yield and narrow emission spectra. However, planar QD films often exhibit limited light extraction efficiency and weak light-matter interactions, thereby restricting their overall color-conversion performance. In this paper, we propose a strategy based on nanoimprinting lithography (NIL) for fabricating color-conversion thin films of CdSe/ZnS QDs incorporating ultrathin metasurface structures. The QDs are embedded in a high-refractive-index (1.98@442 nm) dielectric resin cured by ultraviolet light, forming nanostructures that simultaneously function as emitters and resonators. By carefully engineering the metasurface geometry, the structures are designed to support photonic modes overlapping with the QD absorption band, thereby enabling a strong photoluminescence (PL) enhancement via resonant coupling. Compared with planar QD films, the imprinted structures achieve a pronounced 3.8-fold increase in emission intensity, accompanied by an enhanced Purcell factor from 1.173 to 1.955. This study demonstrates that NIL provides a versatile and scalable route for integration QDs into high-refractive-index nanophotonic architectures, enabling efficient light-matter interactions. The approach offers a promising pathway toward large-scale, high-performance color-conversion devices for next-generation display applications.