Red-light excited efficient metal-free near-infrared room-temperature phosphorescent films.

A set of red-light-excited, metal-free room-temperature phosphorescence (RTP) systems was constructed with brominated phenolsulfonephthaleine derivatives. The best metal-free RTP system has the reddest near-infrared (NIR) RTP emission (λ p = 819 nm) with the highest phosphorescence quantum yield (Φ RTP  = 3.0%) so far identified. The RTP emission can be switched ON-OFF by adding acid and alkali alternately. A logic operation with half-subtractor function and dual-channel response (visible light emission/NIR RTP emission) was also constructed based on these properties.