Aqueous/Alcohol‐Soluble Carbon Dot Light‐Emitting Diodes

ABSTRACT

Fluorescent carbon dots (CDs), benefiting from their environmental friendliness, solution processability, tunable emission spectra, and high photoluminescence efficiency, have shown great promise for next‐generation solid‐state lighting and flat panel displays. CDs are typically synthesized via hydrothermal methods, exhibiting excellent solubility in water and alcohols. However, due to the absence of suitable alcohol‐soluble host materials, aqueous/alcohol‐soluble CDs have so far failed to achieve electroluminescence. Herein, a bipolar host material named 2PCT is specifically designed for aqueous/alcohol‐soluble CD‐based electroluminescent light‐emitting diodes (LEDs). Specifically, the introduction of donor‐acceptor units and diethyl phosphite groups enables 2PCT to have excellent bipolar transport properties and film‐forming capability. Moreover, the high solubility of 2PCT in ethanol and low production cost position it as a promising candidate for large‐scale green manufacturing of CD‐based LEDs. Using 2PCT as the host material, we have successfully fabricated multicolor (green, yellow, and red) CD‐LEDs with record‐breaking performance benchmarks among ethanol‐processed CD‐based optoelectronic devices. Benefiting from the alcohol‐compatible processing, we have further achieved air‐stable fabrication of CD‐LEDs with an extended emission area of 16 cm ² , which holds significant potential for large‐area optoelectronic applications.