Polyvinyl alcohol-based room-temperature phosphorescent materials: from functional group engineering to advanced...

Room-temperature phosphorescence (RTP) has attracted considerable attention in optical security, information protection, and environmental sensing. However, achieving efficient RTP remains challenging due to the spin-forbidden nature of triplet transitions and the high susceptibility of triplet excitons to environmental quenchers. In polymer matrices, these issues are often aggravated by phase separation and molecular aggregation, making constructing high-performance RTP systems more demanding. Polyvinyl alcohol (PVA) offers an ideal rigid microenvironment for doped phosphors, as its dense hydrogen-bonding network suppresses non-radiative transitions and protects triplet states from oxygen and moisture. In this review, we classify PVA-based doped RTP materials according to the substituents attached to the dopant chromophores. From the perspective of molecular design and structure-property relationships, we discuss how different substituent types modulate phosphorescence lifetime, quantum yield, and emission color. We further highlight the applications of these materials in time-resolved anti-counterfeiting, multi-level encryption, explosive vapor detection, and latent fingerprint imaging, and provide future perspectives. This review establishes a substituent-centered framework for PVA-based doped RTP systems, summarizing recent advances in molecular design and modulation strategies to elucidate the fundamental operating principles of the PVA host.