The Regulation Strategy of Biomass-Derived Full-Color Carbon Dots and its Applications to Warm White Light-Emitting Diodes with Ultra-High CRI-96.2

Abstract

Biomass-derived carbon dots, which become a new generation of fluorescent materials, are expected to be a key component in building new optoelectronic devices. However, its insufficient photoluminescence quantum yield (PLQY) and lack of an effective emission band limit its further application. In this work, biomass-derived full-color (415–650 nm) carbon dots (CDs) were prepared by a one-step solvothermal method, defatted Sichuan pepper seed biowaste as a precursor carbon source and 1,4-dihydroxynaphthalene as a modifier to modulate the formation of its conjugated domains, and synthesized in different solvents to modify their surface structure. Meanwhile, Solutions of the optical tri-color blue CDs, green CDs, and red CDs (blue CDs: 82 %, green CDs: 62 %, and red CDs: 48 %) with high QY were selected, while solutions of white CDs (W-CDs) were prepared by modulating their ratios. They were embedded in polyvinylpyrrolidone (PVP) and starch to construct solid phosphors, which could be served as a color conversion layer for light-emitting diode (LED)，to suppress their self-quenching properties. The final package achieves optical tri-color LED as well as a warm white LED with a high color rendering index (CRI) of 96.2 and color coordinates (CIE) of (0.40, 0.39).

Keywords: biomass, Full-color CDs, High QY, warm W-LED, ultra-high CRI