Ultra-long room-temperature phosphorescent carbon dots: pH sensing and dual-channel detection of tetracyclines
Currently, the synthesis and applications of room-temperature phosphorescent (RTP) materials are promising, but challenging. Hereby, one kind of ultra-long phosphorescent carbon dots (P-CDs) was rapidly prepared through a facile microwave-directed way. Meaningfully, the yellow-green phosphorescence of the P-CDs was observed up to 9 s, and their fluorescence and phosphorescence showed at 418 nm and 525 nm by the same excitation at 354 nm. Simultaneously, the RTP intensity of P-CDs gradually decreased with increasing pH because protonation dissociated hydrogen bonds and disturbed the phosphorescent sources, while their fluorescence exhibited the general stability over a wide pH range of 2.1-12.68. Significantly, we found both fluorescence and phosphorescence of P-CDs were quenched by introducing tetracyclines (TCs). To be specific, the P-CDs described here were rich in -COOH and -OH groups on their surfaces, which facilitated CDs to link with TCs together, thus resulting in inner filter effect process (IFE) occurred. Moreover, P-CDs showed the potential as the ideal candidate for building up the dual-channel assays towards the targets.