Multi-response upconverted ultraviolet-C photons for tagging and sterilization

Abstract

Ultraviolet-C (UVC) photons have the potential to be used in a broad spectrum of fields, like sterilization and tagging. However, there is little natural UVC component on the Earth's surface due to the absorption of sunlight by the ozone layer, thus making exploitation of artificial UVC light a meaningful issue. This study introduces a strategy for generating UVC emission via an upconversion mechanism from Pr³⁺-doped SrSiO₃ upon irradiation of visible light. The excitation sources include the commonly used blue laser diode (LD) emitting at 450 nm, as well as sunlight. The dependence of UVC intensity on the power density of 450 nm LD indicates that the UVC emission stems from a two-photon upconversion process. The UVC photons from the as-prepared Pr³⁺-doped SrSiO₃ are then used for high signal-to-noise ratio and even background-free tagging in several complex scenarios and also for sterilization. In one word, our work enriches the upconversion luminescent materials emitting in the UVC wavelength range and demonstrates the potential applications of upconverted UVC photons, including tagging and sterilization.