Ambient Temperature Synthesis of Ultraviolet Emissive Carbon Quantum Dots from Kakadu Plum
Abstract
We proposed for the first time an efficient, environmentally friendly and energy-saving method for synthesizing carbon quantum dots at room temperature (RT.C-QDs). The Kakadu plum powder was used as a sole precursor without the use of external energy sources and chemical oxidants. The systematic analysis of as-synthesized RT.C-QDs reveals that they are composed of highly crystalline carbon quantum dots with an average diameter of 3.9 nm and exhibit an excitation-dependent emission characteristic with a quantum yield of 8.5%. The emission peak of RT.C-QDs was in a UV region at wavelength of 325 nm with high-color purity of narrow full width at half maximum (FWHM) at 50 nm, which is considered among the narrowest FWHMs reported to date. The obtained RT.C-QDs showed remarkable properties, including a unique graphitic carbon core encapsulated in an oxygen-rich amorphous shell, excellent water solubility, photostability, and environmental (pH) stability. This achievement could have significant implications for sterilization and photocuring applications and provide a promising direction for the development of practical and industrial ambient-temperature fabrication of carbon quantum dots.