Perovskite nanocrystals (PeNCs) have been regarded as one of the most promising candidate materials for next-generation display technology due to their remarkable optical performance. However, addressing the limitations of inherent instability and low luminescence efficiency of PeNC films is still a huge obstacle in its commercialization process. Herein, the low-cost and large-area perovskite nanocrystal composite films (NCFs) based on hexagonally distributed TiO 2 -based metasurface (inspired by the surface structure of butterfly wings) in combination with PeNCs encapsulated in PMMA matrix were fabricated. The photoluminescence intensity of perovskite NCFs can be enhanced by a maximum of 3.89 times based on the Purcell effect by tailoring to match the emission peaks of their PeNCs in various bands using the flexibility of metasurface design. The encapsulation of PMMA polymer and TiO 2 nanocavities also effectively enhanced the stability of PeNCs. Benefiting from these favorable characteristics, perovskite NCFs are applied to liquid crystal displays (LCDs) as color conversion layers, with color gamut reaching 122% of the NTSC standard and 180% of the commercial LCD screen, respectively, demonstrating that perovskite NCFs possess enormous potential in the high-end display fields. Furthermore, this metasurface fabrication process avoids complicated, time-consuming, and expensive process flow, laying the foundation for further commercialization beyond the laboratory.
The main contribution of semiconductor nanomaterials to surface-enhanced Raman scattering (SERS) comes from charge transfer (CT) between the absorbing molecules and the semiconductor. However, it is still challenging to realize the combined effects of the electromagnetic mechanism (EM) and the chemical mechanism (CM) for semiconductor-based SERS substrates. Herein, we demonstrate and design double-shelled ZnO (ZnO-DS) hollow microspheres by a modified hydrothermal/solvothermal process. SERS experiments and theoretical simulations proved that the excellent SERS activity is mainly attributed to the combined effect of Mie resonances generated by the nanocavities in the unique hollow double-shell nanoparticles and the CT effect excited by special structure ZnO. Particularly, the produced ZnO-DS SERS substrates exhibited a low limit of detection (LOD, 1 × 10–7 M for 4-MPY), outstanding sensitivity (EF = 1.2 × 104), and high stability (RSD = 10.4%, over 30 days of storage at room temperature). Furthermore, benefiting from the matching of energy levels of the ZnO-DS substrate and probe molecules, the sulfhydryl molecules with similar structures could be selectively distinguished in complex environments. We visualize that this work will resolve the current dilemma between sensitivity and selective detection of SERS substrates and expect to enable the monitoring of target molecules in the environment containing complex mixtures such as food safety and environmental protection.
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