Red emission carbon dots for microLED application

Abstract

Fluorescent carbon dots (CDs) are one class of carbon-based nanomaterials that exhibit special photoluminescence properties. The unique properties of CDs, such as biocompatibility, tunable emission wavelength, and cost-effective, synthesis, have aroused intense interest. Conventionally, in the same particle size, the emission wavelength of CDs can be controlled by the graphitization of the monomer precursors. To date, it is still challenging to produce long-wavelength emissive CDs because it requires a higher graphitization degree of precursors. Not many results have been reported for the CDs with the emission wavelength longer than 600 nm (red). In this paper, we report a new type of red emissive CDs with the emission peak at 660 nm under ultraviolet light excitation with 30% quantum yield. Different from the conventional CDs with short Stokes shift, the new CDs exhibit 255 nm Stokes shift. This property will benefit applications of biosensors, solid-state lighting, and electronic displays. Furthermore, the carbon dots can be embedded into UV-curable polymer. With the fast photocuring technology, red emissive polymer pattern can be produced immediately by printing, stamping, or plotting. A red emission microLED was fabricated using CD-embedded polymer to generate a color coordinate at (0.56, 0.42).