Toward the need for solid-state fluorescent quantum dots, resistant to self-quenching, we describe a solvothermal-assisted sol–gel method to synthesize Se quantum dots. Morphological and crystalline characterizations reveal that Se quantum dots (average size 3–8 nm) have a trigonal crystal structure. The presence of planar defects (dislocations, stacking faults, twins, and grain boundaries) suggests formation of Se nanocrystallites through aggregation-based crystal growth mechanisms. Under ultraviolet excitation, the quantum dots exhibit an excitation wavelength-dependent solid-state blue emission with an average lifetime of 1.96 ns. Depending on fluorescence quenching by curcumin, selenium quantum dots act as ideal candidates for inner filter effect-based curcumin sensing.

No abstract

We have developed a green, facile and economical route to synthesise luminescent carbon quantum dots from pulp free juice of Citrus limon in ethylene glycol. The obtained graphitic carbon dots with an average size of 3 nm exhibits strong UV absorption. Dependence of excitation wavelength on blue emitting carbon dots is investigated. This spectral behaviour remains unchanged with sulphur doping in carbon dots. They show good biocompatibility while inhibiting the growth of DLA cancerous cells. Moreover optical properties of S-doped carbon quantum dots are utilised to detect hydrogen peroxide with a detection limit of 0.49 mM. GRAPHICAL ABSTRACT

No abstract