Local Constraints on Junctions to Strengthen Near-Infrared Phosphorescence of Organic Dyes

A strategy involving the effect of the local constraint on junctions for doping-induced phosphorescence was proposed to increase the rigidity of hydrogen-bonded polymer to inhibit the nonradiative decay of the organic phosphorescent dyes and was verified by bromophenol blue (BPB) derivatives as the near-infrared (NIR) phosphorescent dye. It is shown that the effect of local constraints on junctions of beta-cyclodextrin in the poly(vinyl alcohol) (PVA-LCPN) matrix can effectively improve the quantum yields of NIR phosphorescence of BPB derivatives. On the basis of the verification and optimization of the system through response surface analysis, the quantum yield of TBPB@PVA-LCPN film based on NIR emission could be increased up to 77% compared with that of TBPB@PVA, reaching 5.3%, and the quantum yield in the NIR region could be improved to 3.6%. The results of response surface analysis are consistent with the phenomenon of our proposed strategy, which can inspire the production of organic materials with NIR RTP emission. Together, this could inform efficient and cheap strategies for increasing the quantum yield of the doping RTP materials.