Boric Acid Cross-Linking Strategy for Enhancing Room Temperature Phosphorescence of Poly(Vinyl Alcohol)-Doped Films

Organic room temperature phosphorescence (RTP) has attracted increasing attention owing to its unique luminous properties and wide applications. However, the trade-off between the phosphorescence quantum yield (ΦPhos) and the phosphorescence lifetime (τPhos) highlights the necessity for developing new strategies to enhance RTP performance. While research often focuses on guest components in polymer-based host–guest RTP systems, the host materials, which provide rigid environments, are less explored. This work introduces a simple and efficient strategy to develop RTP materials with high efficiency and long lifetime by employing covalent cross-linking to modify the rigidity of the polymer matrix. By suppressing nonradiative decay and decreasing luminescence quenching under ambient conditions, not only the ΦPhos of cross-linked films is improved from 3.2% to 13.5%, but also the τPhos is extended from 482.34 to 625.23 ms. Thanks to its solution processability and water sensitivity, this RTP system was successfully applied in inkjet printing and binary anticounterfeiting.