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As a new class of fluorescent carbon nanomaterials, CQDs possess the attractive properties of high stability, good conductivity, low toxicity, environmental friendliness, simple synthetic routes as well as comparable optical properties to quantum dots. [6] Carbon quantum dots have been extensively investigated especially due to their strong and ...
where μ is the reduced mass, a is the radius of the quantum dot, m e is the free electron mass, m h is the hole mass, and ε r is the size-dependent dielectric constant. Although the above equations were derived using simplifying assumptions, they imply that the electronic transitions of the quantum dots will depend on their size.
A CNT QD is formed when electrons are confined to a small region within a carbon nanotube. This is normally accomplished by application of a voltage to a gate electrode, dragging the valence band of the CNT down in energy, thereby causing electrons to pool in a region in the vicinity of the electrode.
A single-walled carbon nanotubes (SWCNT) can be envisioned as strip of a graphene molecule (a single sheet of graphite) rolled and joined into a seamless cylinder.The structure of the nanotube can be characterized by the width of this hypothetical strip (that is, the circumference c or diameter d of the tube) and the angle α of the strip relative to the main symmetry axes of the hexagonal ...
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.
A carbon nanothread (also called diamond nanothread) is a sp 3-bonded, one-dimensional carbon crystalline nanomaterial. The tetrahedral sp 3 -bonding of its carbon is similar to that of diamond . Nanothreads are only a few atoms across, more than 300,000 times thinner than a human hair .
These silicon quantum dots can be used in numerous situations which include photochemical and biological applications such as the use of silicon layers for photovoltaic applications. [23] In an experiment using silicon quantum dots near the interface of the substrate and the quantum dots, the power conversion efficiency of the solar cell increased.
Fluorescence arises from photoexcitation in these quantum dots and is easily tuned to the visible or near infrared region of the spectrum, by choice of semiconductor material and particle size, making quantum-useful fluorophores. Quantum dots have many properties of interest in order to be used as chemical sensors, including their high ...