Tunable multicolor room-temperature phosphorescence including white-light emission from amorphous copolymers

Research on amorphous pure organic room-temperature phosphorescent (RTP) materials has been receiving great attentions in recent years, while smart materials with color-tunable RTP emission are still rare, especially those with white-light emission and white afterglow. A series of pure organic amorphous copolymers with dual-emissive RTP have been synthesized by copolymerizing benzoic acid, 4-bromo-1,8-naphthalic anhydride and acrylamide with different feeding ratios. The two phosphor moieties display different absorption spectra, different RTP emission spectra and lifetimes, which can induce tunable multicolor RTP with different feeding ratios and different excitation wavelengths, including white-light emission (CIE coordinates (0.32, 0.33)). Moreover, time-dependent multicolor afterglow can also be observed because of the different decay lifetimes of these two phosphors, including nearly white afterglow. Since the acrylamide polymers are water-soluble, their RTP emission can be quenched with the existence of water by breaking the rigid structure, which makes their emission color tunable under different humidity conditions.