Matrix-free room-temperature phosphorescent boron and nitrogen co-doped carbon dots for information encryption and anticounterfeiting

Abstract

The phenomenon of long afterglow of carbon dots has recently attracted great interest. It is still challenging to fabricate a matrix-free and simultaneously long-lived afterglow material, especially a room-temperature phosphorescent (RTP) material, through a simple and effective way. Herein, we propose a simple and rapid one-step hydrothermal method for synthesizing matrix-free ultralong-lifetime room-temperature phosphorescent (URTP) boron and nitrogen co-doped CDs (B, N-CDs) using ethylenediaminetetraacetic acid disodium salt and boric acid. The as-prepared material exhibited blue fluorescence emission at 408 nm with excitation at 319 nm. Furthermore, B, N-CDs displayed URTP with a lifetime of 1.261 s. B and N elements promote the n–π* transition and intersystem crossing (ISC) and can effectively reduce the energy gap, and the formation of long-chain polymers based on the carbon core surface and the existence of hydrogen-bonded skeletons also play a crucial role in the generation of URTP. The facile preparation and unique optical features of these B, N-CDs make them promising candidates for information encryption and anticounterfeiting applications.