Yellow-Emitting Carbon Nanodots and Their Flexible and Transparent Films for White LEDs

ACS Appl Mater Interfaces. 2016 Dec 7;8(48):33102-33111. doi: 10.1021/acsami.6b12113. Epub 2016 Nov 29.

Abstract

We report carbon nanodots that can be utilized as effective color converting phosphors for the production of white light-emitting diodes (LEDs). Blue-excitable and yellow-emitting carbon nanodots, functionalized with 3-(imidazolidin-2-on-1-yl)propylmethyldimethoxysilane (IPMDS)-derived moieties (IS-CDs), are synthesized by a novel one-pot reaction in which the products from the initial reaction occurring between urea and 3-(2-aminoethylamino)propylmethyl-dimethoxysilane (AEPMDS) are further treated with citric acid. Distinctive from the majority of carbon nanodots reported previously, IS-CDs emit at 560 nm, under 460 nm excitation, with a quantum yield of 44%. Preliminary toxicity studies, assessed by the Artemia franciscana nauplii (brine shrimp larvae) bioassay, indicate that IS-CDs are largely nontoxic. Furthermore, the IS-CDs form flexible and transparent films without the need of encapsulating agents, and the solid films retain the optical properties of solvated IS-CDs. These features indicate an immense potential for the IS-CDs as an environmental-friendly, blue-excitable carbon nanodot-based phosphor in solid-state lighting devices.

Keywords: carbon nanodots; organosilane; photoluminescence; solid-state nanomaterials; surface characterization; surface functionalization.