Cd-Rich Shell-Engineered ZnCdS Nanocrystals for Ultrahigh-Performance Adjustable Shielding of Ultraviolet–Blue Light

Excessive exposure to ultraviolet (UV)-blue light (250-500 nm) has detrimental effects on human health, polymeric materials, and natural substances. The development of stable, efficient, and multifunctional materials capable of selectively absorbing harmful UV-blue light while preserving high transparency at longer wavelengths remains highly desirable yet challenging. Herein, we report a Cd-rich shell-engineering strategy to precisely tailor the band-edge states of ZnCdS nanocrystals (NCs), thereby achieving markedly enhanced the colloidal solution's absorption (optical path: 1 cm) in the UV-blue region, with nearly complete blocking of hazardous radiation (<1% transmittance at 500 nm), while maintaining outstanding optical transparency (>90% transmittance above 528 nm). Moreover, incorporation of ZnCdS@Cd-rich NCs into ethyl cellulose polymer matrix enables the fabrication of transparent composite films with excellent UV-blue light shielding ability, effectively protecting organic substrates such as wood against photodegradation. Even under laser diodes radiation, the NC-based transparent film still can possess outstanding shielding performance. The introduction of Cd-rich shell engineering as a versatile strategy to enhance short-wavelength absorption in semiconductor NCs, enabling the fabrication of optical films that effectively block harmful UV-blue light while maintaining high visible transparency, offering promising applications in optical filters and protective coatings.