Solid-State Fluorescent Selenium Quantum Dots by a Solvothermal-Assisted Sol–Gel Route for Curcumin Sensing

Abstract

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.

Tailoring the Optical Properties of Selenium Nanoneedles by Pulsed Laser Ablation in Liquids: Implications for Solar Cells and Photocells

“…At 525 nm, the PL emission shows a relatively slow decay time of ∼1.21 ns compared to a decay time of ∼0.03 ns at 700 nm. While the measured PL decay times of Se needles at 525 nm are comparable to those of solid-state Se quantum dots, which are intrinsic decay times of the photoexcited excitonic states, the decay time of the near-band-edge emission at 700 nm is much shorter. The short decay time of the near-band-edge emission is likely to be related to the bare (unpassivated) surface of Se needles, which rapidly quenches the photoexcited carriers.…”

A mini review on selenium quantum dots: synthesis and biomedical applications

“…(E) Solvothermal synthesis of SeQDs in the presence of TEOS. Reproduced, with permission, from Anupama et al (2021) . Copyright 2021, American Chemical Society.…”

Biosensors Based on Inorganic Composite Fluorescent Hydrogels

“…Destabilization via ligand removal weakens the short-range interactions that hold the NCs apart and induce aggregation due to van der Waals attraction. However, this can lead to the formation of aggregates in the gel and loss of fluorescence properties of the NCs [50,51]. The sol-gel transition is usually initiated by optical irradiation, thermal treatment, or chemical destabilization of the sol, either spontaneous or caused by chemical agents.…”