Light-activated uvc-emitting upconversion coating for antimicrobial surfaces

Overview

This solution is a light-activated, UVC-emitting upconversion coating designed to provide continuous, chemical-free antimicrobial protection on everyday surfaces. The coating uses praseodymium-doped upconversion materials that convert ambient visible light into germicidal UVC radiation (under 300 nm), turning disinfection on automatically when surfaces are exposed to light and off when they are touched or shaded. It addresses key limitations of conventional photocatalyst-based antimicrobial coatings, including prohibitively low oxidant generation efficiency under ambient light, non-selective oxidant activity, and public and regulatory concerns about nanoparticle release. Direct visible-to-UVC conversion offers a low-cost, scalable, non-toxic, and long-lasting alternative for reducing microbial contamination on household and commercial surfaces.

Technical specifications

Core technology:

• Praseodymium (Pr)-doped upconversion materials that convert visible photons into UVC emission
• Germicidal action activates under ambient or fluorescent lighting and deactivates when light is blocked by touch or shading
• Thin-film coating estimated at under $3 per square meter for a 1-micrometer-thick layer

Planned efficiency improvements:

• Physical vapor deposition synthesis of high-quality thin films with Pr activators and dopants dispersed at optimal interatomic distances
• Glassy or amorphous host films to reduce phonon relaxation energy loss and avoid grain-boundary quenching
• Aluminum plasmonic nanoparticles integrated via scalable patterning to enhance visible light absorption and near-field intensity through surface plasmon resonances

Target applications:

• Kitchen and bathroom surfaces
• Other high-touch household and commercial surfaces requiring continuous passive disinfection

Technology readiness level

The coating concept has been experimentally validated: Pr-doped upconversion material surfaces have demonstrated biofilm inhibition and inactivation of spore-forming bacteria under fluorescent lamp illumination, confirming low cost, chemical-free operation, non-toxicity, and durability. The primary barrier to commercialization identified by the researchers is low visible-to-UVC conversion efficiency. The proposed work targets three specific strategies to overcome this limitation and achieve dramatic efficiency gains, drawing on recent advances in parallel near-infrared-to-visible upconversion photonics. Performance will be validated using surrogate microorganisms, with the goal of enabling scalable, low-cost manufacturing of antimicrobial coatings for broad household and commercial deployment.