Coordinatively improving polymeric phosphorescence lifetime and quantum yield via triplet exciton modulation

The advancement of polymeric materials with exceptional room temperature phosphorescence (RTP) performance is hindered by the competing relationship between long phosphorescence lifetime (τ_P) and high absolute phosphorescence quantum yield (Φ_P). Herein, we present an Iodine-Stretch-Boric Acid (ISB) strategy that synergistically fine-tunes the generation and quenching of triplet excitons, thus enhancing both τ_P and Φ_P. In this strategy, ISB harnesses the external heavy atom effects to facilitate spin-orbit coupling of phosphors, while simultaneously inducing an exceptionally dense cross-linked network within binaphthyl derivative-incorporated polyvinyl alcohol (BINs@PVA) films. This dual modulation engenders an optimization of the non-radiative rate constant ($k_{\mathrm{nr}}^P$) and intersystem crossing rate constant (k_ISC) of phosphorescence emission. Notably, the RTP performance of post-ISB treated DFBN@PVA films attain a notable advancement, with long τ_P of 1239.8 ms@528 nm (28.4-fold increase) and high absolute Φ_P of 33.8% (24.1-fold increase). Meanwhile, ISB strategy improves the durability of the DFBN@PVA films, preserving bright RTP emission after five days of water immersion and 12 hours in acidic, alkaline and hot water, exhibiting substantial potential for multicolor secure information, antibacterial, and water resistant RTP applications.