Basics and Perspectives of Visible and Near‐UV Light‐Induced Defluorination of Perfluoroalkylsubstances by Semiconductor Nanocrystals

Per‐ and polyfluoroalkyl substances (PFASs) have been extensively used across a wide range of industries owing to their exceptional interfacial properties, thermal stability, and chemical resistance. However, their extreme environmental persistence and bioaccumulation have led to serious global concerns. Conventional PFAS destruction typically requires harsh conditions, such as high temperatures, strong redox reagents, or short‐wavelength light irradiation. In contrast, recent studies have demonstrated that highly stable PFASs can be decomposed under ambient conditions by exploiting nonlinear photochemical processes in semiconductor nanocrystals driven by light‐emitting diodes (LEDs). This review provides an overview of PFAS degradation by visible or near‐ultraviolet light irradiation of semiconductor nanocrystals under mild conditions. Rather than exhaustively surveying recent PFAS degradation technologies, we focus on the fundamental physicochemical properties of PFASs and the basic electronic structure, photophysics, and surface chemistry of semiconductor nanocrystals, and discuss how these factors collectively govern reactivity under visible and near‐ultraviolet light. By emphasizing mechanistic understanding, this review aims to clarify key principles underlying multiphoton‐driven PFAS decomposition and to bridge the knowledge gap between PFAS chemistry and semiconductor nanocrystal science.