Synthesis process of high-efficiency carbon quantum dot materials from orange peel biomass and the materials obtained from this process.

Abstract

The invention relates to a process for synthesizing CQDs from orange peel via controlled pre-carbonization combined with hydrothermal reaction in a citric acid-containing environment and nitrogen source. The process enables the creation of blue-emitting CQDs with an emission peak in the range of 410–430 nm, a fluorescence quantum yield of approximately 21.7%, an average size of approximately 4.6 nm, and a fluorescence lifetime of approximately 7.97 ns. The luminescence spectrum of the material has emission components assigned as phonon-free lines and phonon subbands with an energy gap of approximately 0.21 eV, suggesting the involvement of electron-phonon interactions in the emission process. The process uses inexpensive biomass feedstock, has simple synthesis conditions, and has potential applications in sensors, luminescent materials, and optoelectronic devices.