Visible-light-excited room-temperature phosphorescent carbon dots: preparation strategies, mechanisms, and applications

Visible-light-excited room-temperature phosphorescent carbon dots (RTP CDs) have attracted extensive attention by virtue of their deeper penetrability, less harmful nature, and stronger usability, exhibiting enormous application prospects in information encryption, graphic security, and fingerprint detection. However, achieving visible-light-excited RTP CDs under environmental conditions remains a serious challenge due to the limited excitation region. Recently, researchers have successfully obtained long lifetime and excellent stability visible-light-excited RTP CDs by adjusting the energy level structure of electronic transitions and the conjugated size of CDs to achieve a red-shift in the excitation spectrum. This review provides an overview of the recent developments in visible-light-excited RTP CDs. Firstly, the developmental history, luminescence mechanism, preparation strategy, and property regulation of visible-light-excited RTP CDs were systematically summarized. Additionally, potential applications of visible-light-excited RTP CDs in information protection, image encryption, and fingerprint recognition were also discussed. Finally, we proposed the new opportunities and important challenges of visible-light-excited RTP CDs. This review article provides a comprehensive overview of the latest developments in visible-light-excited RTP CDs, which includes the luminescence mechanisms, preparation strategies, property regulation, and potential applications.