Nanocarbon fluorescence materials are promising color converters for multicolor emission via phosphor-coated light emitting devices (LEDs). Herein, a facile time-controlled solvothermal route was developed to prepare solid-state multicolor nanocarbon emitters comprising dot/sheet nanohybrids. The nanocarbons demonstrate an aggregation-induced color switching behavior, leading to tunable light emission from blue to yellow by modulating the solvothermal reaction time. Particularly, these emitters show outstanding film-forming ability directly and a high production yield (∼40%). Moreover, the nanocarbon-coated ultraviolet LEDs exhibit high quality multicolor light emission and excellent color stability at high voltages, impelling the development of emerging carbon phosphors in fundamental research studies and practical applications.