Search results
Results from the WOW.Com Content Network
A 40-F supercapacitor with a maximum voltage of 3.5 V that employed forest-grown SWNTs that are binder- and additive-free achieved an energy density of 15.6 Wh kg −1 and a power density of 37 kW kg −1. [138] CNTs can be bound to the charge plates of capacitors to dramatically increase the surface area and therefore energy density. [2]
Carbon quantum dots also commonly called carbon nano dots or simply carbon dots (abbreviated as CQDs, C-dots or CDs) are carbon nanoparticles which are less than 10 nm in size and have some form of surface passivation.
Their diameters (2 - 10 nm) are on the order of the exciton Bohr radius, resulting in quantum confinement effects analogous to the "particle-in-a-box" model. As a result, optical and electronic properties of quantum dots vary with their size: nanocrystals of larger sizes will emit lower energy light upon fluorescence excitation. [23]
Another application of this technique involves using Zinc Sulfide quantum dots to treat industrial waste water. [18] Indium An alternative to the heavy metal quantum dots are quantum dots that contain Indium. One example is the use of CuInS2 quantum dots as fluorescent labels that emit light in the near infrared region of the visible spectrum. [19]
For environmental applications, quantum dot surfaces can be modified with antibodies that bind specifically to microorganisms or other pollutants. Spectroscopy can then be used to observe and quantify this spectrum shift, enabling precise detection, potentially on the order of molecules. [38]
When a quantum dot is illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conduction band .
[30] [31] Nanoparticles have been used as quantum dots and as chemical catalysts such as nanomaterial-based catalysts. Recently, a range of nanoparticles are extensively investigated for biomedical applications including tissue engineering, drug delivery, biosensor. [32] [33]
Silicon quantum dots are metal-free biologically compatible quantum dots with photoluminescence emission maxima that are tunable through the visible to near-infrared spectral regions. These quantum dots have unique properties arising from their indirect band gap , including long-lived luminescent excited-states and large Stokes shifts .