Defect and interface engineering of visible-light-active semiconductor nanomaterials for sustainable photocatalytic pathogen inactivation.

Antimicrobial resistance and the presence of potent microbial entities in water and biological matrices have been major challenges to traditional chemical and thermal disinfection techniques. Although semiconductor-based photocatalysis is a promising and non-invasive oxidative technology, the use of pure photocatalysts is often restricted by their large optical bandgaps and high rates of charge-carrier recombination. The use of photocatalysis for environmental remediation is widely reviewed in the current literature, but the specific design criteria for such materials to effectively counteract complex biological entities are not well represented. In this review, we discuss the importance of band engineering as a critical mechanism to ensure that the redox potentials of semiconductor materials are aligned to the specific reactive oxygen species required to effectively counteract potent microbial entities such as biofilms and viruses. We critically discuss specific strategies to modulate the electronic density of states to improve the optical properties of semiconductor materials while maintaining their high redox potentials for ensuring biosafety. This review is a critical amalgamation of solid-state physics and microbiology to define the thermodynamics and kinetics required to develop targeted and highly potent photocatalytic materials for water purification, self-sterilizing surfaces and wearable devices.