A central theme in nanotechnology, quantum dots can tune their band gap, which enables these to control the frequency of light emission and absorbance.
Quantum dots (QDs) are semiconducting particles that are a few nanometres in size. Due to their small size, these can confine electrons’ motions. These have the ability to tune their band gap, which enables these to control the frequency of light emission and absorbance. After absorbing a photon of light, these emit a photon of longer wavelength. Wavelength of the emitted photon can be controlled by controlling the size of QDs. Hence, it is possible to control their properties (electrical and optical) according to their use.
A full range of QDs can be manufactured, each with a narrow, distinct emission spectrum by manipulating the colour of light emitted from these. QDs emit light of a particular colour after being illuminated by light. The colour depends on the size of the nanoparticle, that is, difference between conduction band (CB) and valence band (VB). The smaller the nanoparticle, the larger the difference between CB and VB, resulting in a deeper blue colour. For a larger nanoparticle, the difference between CB and VB is lower, which shifts the glow towards red.
Recently, a NASA technologist has teamed with the inventor of a new nanotechnology that could transform the way space scientists build spectrometers. It is an important device used by all scientific disciplines to measure the properties of light emanating from astronomical objects, including Earth.
Absorption spectrometers measure absorption of light as a function of frequency or wavelength due to its interaction with a sample, such as atmospheric gases. This technology allows instrument developers to generate nearly an unlimited number of different dots, and have precise control over what each dot absorbs. It helps them customise instruments to observe many different bands with high-spectral resolution. This emerging technology could give scientists a more flexible, cost-effective approach for developing spectrometers.
This story is from the November 2018 edition of Electronics For You.
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This story is from the November 2018 edition of Electronics For You.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.
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