Efficient resistance against solid-state quenching of carbon dots towards white light emitting diodes by physical embedding into silica

To overcome self-quenching of carbon dots (CDs) in solid state and provide a universal strategy for efficient luminescence of CDs in solid state, this paper reports a novel method of physical embedding of solid-state CDs into a silica matrix. CD/silica composites were prepared through injecting N-(3-(trimethoxysilyl) propyl) ethylenediamine into a CD aqueous solution and have exhibited a high quantum yield of 41.72%. A mechanism of photoluminscence (PL) quenching in solid-state CDs and PL resuming in CD/silica composites was proposed. These CD/silica composites possess excellent film-forming ability, thermostability and ultraviolet (UV) stability. By taking advantage of these remarkable properties, a white light-emitting diode was constructed by combining CD/silica film with a UV chip, which has exhibited warm white light emission with Commission Internationale de L'Eclairage coordinates of (0.44, 0.42) and correlated color temperature of 2951 K. It is evident that CD/silica composites have superior potential in solid-state lighting system. (C) 2017 Elsevier Ltd. All rights reserved.