Tunable ultralong multicolor and near-infrared emission from polyacrylic acid-based room temperature phosphorescence materials by FRET

Polymer-based room temperature phosphorescence (RTP) materials have received significant attention for their potential application in various fields. However, the development of polymer-based RTP materials with persistent multicolor and near-infrared (NIR) emission still faces great challenges. Herein, 4-carboxyphenylboronic acid (CPBA) is facilely doped into polyacrylic acid (PAA) matrix to construct an ultralong RTP material PAA-CPBA, which is the better candidate of energy donor owing to the wide phosphorescence emission band. Two commercial fluorescent dyes rhodamine B (RhB) and fluorescein (FL) are selected as energy acceptors to prepared ternary systems PAA-CPBA-RhB and PAA-CPBA-FL, and tunable multicolor afterglow from blue to red and yellow is realized through phosphorescence Förster resonance energy transfer (FRET). More interestingly, the quaternary doping system PAA-CPBA-RhB-FL exhibits a nearly white afterglow emission. Significantly, a commercial NIR dye Nile blue (NiB) is used to fabricate the other quaternary doping systems PAA-CPBA-RhB-NiB, and persistent luminescence in NIR region is successfully achieved via stepwise FRET using RhB as an intermediate acceptor. Furthermore, due to the different persistent luminescence performance, the multicolor PAA-based RTP materials are successfully applied in multiple information encryption and multicolor displays.