Anti-self-quenching tunable solid-state fluorescent carbon dots for white light emitting diodes

Solid-state luminescent materials based on carbon dots (CDs) have been widely investigated in light-emitting devices because of their excellent optical properties. Severe fluorescence quenching effects, however, induce the self-quenching resistant of CDs. In this work, anti-self-quenching fluorescent carbon dots of B-CDs and YG-CDs were obtained by one-step hydrothermal treatment of phthalic acid and ethylenediamine at different temperatures of 160 °C and 240 °C, respectively. Analytical studies of UV absorption, fluorescence lifetime and fluorescence emission revealed that the solid-state fluorescence of B-CDs and YG-CDs may be related to their lower sp2 structural domain content, while a possible factor affecting the solid-state redshift is the increase of nitrogen-related surface defects. The red-shifted fluorescence of YG-CDs from aqueous solution to solid state is attributed to resonance energy transfer (RET) or reabsorption. Crucially, solid-state emitting B-CDs and YG-CDs have been successfully employed in the assembly of monochromatic LEDs and WLEDs (0.30, 0.29) on UV chips, underscoring their significant potential for advancing solid-state lighting systems integrated with CDs. This work provides an effective strategy for developing anti-self-quenching luminescent materials integrated with CDs for advanced optoelectronic devices.