One-pot Solvothermal Synthesis of Full-color Carbon Quantum Dots for Application in Light Emitting Diodes

Abstract

Full-color Carbon Quantum Dots (FCQDs) have intrinsic characteristics as components for White Light Emitting Diode (WLED) technology, but are not yet applied in the current lighting industry. In this work, FCQDs were prepared by optimizing the synthetic route in order to obtain a simple and one-step solvothermal carbonization of citric acid and urea in dimethylformamide. The synthesis at 166 °C for 11 h and 24 min (FCQD2) was selected from spectroscopy in the ultraviolet–visible (UV–Vis) region and its fluorescence indicated emission over almost the entire visible region of the electromagnetic spectrum with a 380 nm excitation source and a concentration of 0.22 mg mL −1. The morphological, structural and optical properties were evaluated and they showed that nanoparticles with dimensions between 2 and 10 nm consisted mainly of carbon atoms with functional groups on the surface. FCQD2 was incorporated in a polymeric matrix (PVA) and the coordinates of the Color Rendering Index (CRI) showed better color quality than a commercial WLED. It appears that FCQD2, with an easy synthesis and being ecofriendly, has potential for incorporation in a solid matrix, as well as application in WLEDs for the improvement of optoelectronic devices, replacing inorganic quantum dots.