Mercury-Free Lamp-Phosphor Coupling for UVC Surface Decontamination

Microbiological contamination of surfaces is a significant issue across various sectors, posing a serious risk of pathogen transmission between individuals and impacting public health. Among the available decontamination methods, ultraviolet-C (UVC) radiation has seen a surge in popularity in recent years, particularly following the COVID-19 pandemic. However, concerns have been raised regarding the environmental impact and the risk for users of mercury-containing UVC devices. Despite their well-documented biocidal efficacy against a broad spectrum of microorganisms, UVC radiation can be significantly hindered by the presence of organic matter, biofilms, or surface irregularities that create shadowed areas. In this study, we present an innovative approach that combines a krypton-chlorine (KrCl) excimer lamp with a UVC phosphor. Optical characterization techniques - including optical emission spectroscopy, camera imaging, and irradiance measurements - were used to analyze the KrCl lamp and two lamp-phosphor combinations, revealing the complementary nature of these two UVC sources. This synergy was further investigated and validated against two bacterial species (Escherichia coli and Staphylococcus aureus) and the HAdV5 adenovirus. The promising results highlight new opportunities for enhancing UVC-based surface decontamination strategies by combining UVC radiation sources.