Journal Article carbon dots energy transfer 059QF0KO0R 3FPU23BG52 7440-44-0 Carbon Luminescent Agents Research Support, Non-U.S. Gov't TADF Toluene Water advanced encryption blue phosphorescent carbon carbon dot carbon nanodots finger printing lighting luminescence multicolor afterglow nanodots optical information storage phosphorescence phosphorescent materials physical unclonable function smart materials spin-orbit coupling thermally enhanced luminescence time delay