Birch leaf carbon dots: characterization and application in a light-emitting electrochemical cell

Sammanfattning: A new rising star in the carbon nanomaterial family is carbon dots. Carbon dots have received great attention due to their excellent luminescence and low toxicity. In this project, a new carbon dot derived from birch leaves is studied and characterized. The birch leaf carbon dot (BL-CD) exhibits narrow red photoluminescence (peak = 670 nm, full width at half maximum = 23 nm) with a photoluminescence quantum yield of 26% in dilute methanol solution.  The presence of the characteristic peaks of the pigment pheophytin-a in the absorption spectrum and the photoluminescence spectrum of the BL-CD and the absence of a crystal structure together with the narrow and excitation-independent photoluminescence indicate a carbon dot with a non-emissive amorphous structure with emissive molecular sites consisting of the pigment. The photoluminescence quenching of the BL-CDs in solid-state is reduced by the introduction of a hostmaterial. The use of a host enabled the employment of BL-CDs as the emitter in a light-emitting electrochemical cell (LEC). This project paves the way for further development of the environmentally friendly and sustainable BL-CD LEC.