Search results
Results from the WOW.Com Content Network
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 ...
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.
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 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 ...
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.
However, unmodified quantum dots tend to be hydrophobic, which precludes their use in stable, water-based colloids. Furthermore, because the ratio of surface area to volume in a quantum dot is much higher than for larger particles, the thermodynamic free energy associated with dangling bonds on the surface is sufficient to impede the quantum ...
Researchers from Rice University and State University of New York – Stony Brook have shown that the addition of low weight % of carbon nanotubes can lead to significant improvements in the mechanical properties of biodegradable polymeric nanocomposites for applications in tissue engineering including bone, [6] [7] [8] cartilage, [9] muscle [10] and nerve tissue.
However the first macroscopic production of carbon nanotubes was made in 1992 by two researchers at NEC's Fundamental Research Laboratory. [3] The method used was the same as in 1991. During this process, the carbon contained in the negative electrode sublimates because of the high-discharge temperatures.