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Splitting of energy levels for small quantum dots due to the quantum confinement effect. The horizontal axis is the radius, or the size, of the quantum dots and a b * is the exciton's Bohr radius. Band gap energy The band gap can become smaller in the strong confinement regime as the energy levels split up. The exciton Bohr radius can be ...
Typically, the size of the silicon quantum dots is defined by controlling material synthesis. For example, silicon quantum dot size can be controlled by the reaction temperature during thermal disproportionation of silsesquioxanes. [1] Similarly, the plasma residence time in non-thermal plasma methods is a key factor. [2]
Fabrication of the quantum dot LED involved a blue chip as a blue light source and a silicon resin containing the quantum dots on top of the chip creating the sample, with good results obtained from the experiment. [23] Silicon A third type of quantum dot that does not contain heavy metals is the silicon quantum dot.
Some authors have provided evidence of size-dependent fluorescence properties, suggesting that the emission arises from electronic transitions with the core of the dots, influenced by quantum confinement effects, [10] [11] whereas other works, including single particle measurements, [12] have rather attributed the fluorescence to recombination ...
Quantum dots are popular alternatives to organic dyes as fluorescent labels for biological imaging and sensing due to their small size, tuneable emission, and photostability. The luminescent properties of quantum dots arise from exciton decay (recombination of electron hole pairs) which can proceed through a radiative or nonradiative pathway.
Graphene quantum dots (GQDs) are graphene nanoparticles with a size less than 100 nm. [1] Due to their exceptional properties such as low toxicity, stable photoluminescence , chemical stability and pronounced quantum confinement effect, GQDs are considered as a novel material for biological, opto-electronics, energy and environmental applications.
A layer of quantum dots is sandwiched between layers of electron-transporting and hole-transporting materials. An applied electric field causes electrons and holes to move into the quantum dot layer and recombine forming an exciton that excites a QD. This scheme is commonly studied for quantum dot display. The tunability of emission wavelengths ...
Quantum dots (QDs) are nano-scale semiconductor particles on the order of 2–10 nm in diameter. They possess electrical properties between those of bulk semi-conductors and individual molecules, as well as optical characteristics that make them suitable for applications where fluorescence is desirable, such as medical imaging.