Construction of Carbon Dots with Color-Tunable Electrochemiluminescence and Enhanced Efficiency Enabled by Shadow Trapping States and Intramolecular Charge Transfer

Tuning electrochemiluminescence (ECL) color of carbon dots (CDs) with enhanced efficiency is essential for multiplexed biosensing, bioimaging, and energy applications but remains challenging. Herein, we reported a facile route to finely modulate the ECL color of CDs from violet to red, the widest range ever reported, along with a more than 5-fold enhancement of ECL efficiency via phosphorous (P) incorporation. The molecular mechanism was explored experimentally and theoretically, which revealed the unusual dual roles of P dopants in the form of P-C and P-O bonding, i.e., importing shadow trapping states and promoting an effective intra-molecular charge transfer. This work would allow unlocking the key factors of ECL kinetics for heteroatom doped-CDs appearing out of reach, and open a new avenue for the rational design of nanocarbon for desirable applications.