Surface-Modified Carbon Dots with Improved Photoluminescence Quantum Yield for Color Conversion in White-Light-Emitting Diodes

Surface modification of p-phenylenediamine-derived carbon dots using 4-morpholinoaniline with an electron-donating and rigid structure followed by purification using silica gel column chromatography increased the photoluminescence quantum yield from 28.3 to 41.8% in chloroform. The improved photoluminescence quantum yield was observed for the surface modification by postaddition of the surface modifier after the formation of the π-conjugated structure of the carbon dot core but was not observed for the carbon dots prepared from a mixture of p-phenylenediamine and 4-morpholinoaniline. The finding of this work gives us an idea to design carbon dots with high photoluminescence quantum yield for application of color conversion in white-light-emitting diodes.