Rational synthesis of silane-functionalized carbon dots with high-efficiency full-color solid-state fluorescence for light emitting diodes

Abstract

Highly efficient full-color solid-state fluorescent carbon dots (CDs) are very critical for the construction of light-emitting diodes (LEDs), especially white light-emitting diodes (WLEDs), but achieving them is still a challenging task due to the serious self-quenching of CDs in the aggregation state and their complicated photoluminescence (PL) mechanism. Herein, we reported a one-step microwave-assisted method for the large-scale synthesis of solid-state silane-functionalized CDs (SiCDs) with self-quenching resistant and tunable full-color fluorescence. By only controlling the ratio of precursors, the PL emission of these SiCDs can be tuned in the visible region ranging from 438 to 633 nm, accompanied by high quantum yields (QYs) of up to 26-57%. The multicolor emission of these SiCDs is ascribed to their differences in particle size and graphitic nitrogen content, which can be modulated by controlling the dehydration and condensation reactions among raw materials. In addition, based on their excellent optical properties, these SiCDs were directly utilized as phosphors combing with ultraviolet chips to prepare full-color LEDs and all types of WLEDs with adjustable correlated color temperature (CCT) from 3678 to 8158 K and high color rendering index (CRI) of 90–94, demonstrating the tremendous potential for practical lighting applications.