Jaqueline Kiplinger: Difference between revisions
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One particularly important function of quantum dots is their use in lymph node mapping, which is feasible due to their unique ability to emit light in the near infrared (NIR) region. Lymph node mapping allows surgeons to track if and where cancerous cells exist<ref name="Medicine">{{cite journal|last1=Bentolila|first1=Laurent A.|last2=Ebenstein|first2=Yuval|title=Quantum Dots for In Vivo Small-Animal Imaging|journal=Journal of Nuclear Medicine|date=2009|volume=50|issue=4|page=493–496|url=http://jnm.snmjournals.org/content/50/4/493.full|accessdate=5 November 2016}}</ref>. |
One particularly important function of quantum dots is their use in lymph node mapping, which is feasible due to their unique ability to emit light in the near infrared (NIR) region. Lymph node mapping allows surgeons to track if and where cancerous cells exist<ref name="Medicine">{{cite journal|last1=Bentolila|first1=Laurent A.|last2=Ebenstein|first2=Yuval|title=Quantum Dots for In Vivo Small-Animal Imaging|journal=Journal of Nuclear Medicine|date=2009|volume=50|issue=4|page=493–496|url=http://jnm.snmjournals.org/content/50/4/493.full|accessdate=5 November 2016}}</ref>. |
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The use of quantum dots for these functions is especially beneficial because quantum dots emit brighter light, they are excited by a wide variety of wavelengths, and they are more resistant to light than other substances<ref name="chemed" />. |
The use of quantum dots for these functions is especially beneficial because quantum dots emit brighter light, they are excited by a wide variety of wavelengths, and they are more resistant to light than other substances<ref name="Medicine" /><ref name="chemed" />. |
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Quantum dots
Quantum dots are extremely small semiconductors (on the scale of nanometers)[1]. They display quantum confinement in that the electrons cannot escape the “dot”, thus allowing particle-in-a-box approximations to be applied[2]. Their behavior can be described by three-dimensional particle-in-a-box energy quantization equations[2].
The energy gap of the quantum dot is equal to the energy gap of the bulk material plus the energy equation derived from particle-in-a-box, which gives the energy of electrons and holes[2]. Hence, the energy gap of the quantum dot is inversely proportional to the square of the “length of the box,” i.e. the the radius of the quantum dot[2].
Manipulation of the energy gap between the valence band and the conduction band, known as the band gap, allows for the absorption and emission of specific wavelengths[1].
The smaller the quantum dot, the larger the band gap and thus the shorter the wavelength absorbed[1][3].
Different semiconducting materials and are used to synthesize quantum dots of different sizes and therefore emit different wavelengths of light[3]. Materials that normally emit light in the visible region are often used and their sizes are fine-tuned so that certain colors are emitted[1].
Typical substances used to synthesize quantum dots are cadmium (Cd) and selenium (Se)[1][3]. For example, two nanometer CdSe quantum dots emit blue light while four nanometer CdSe quantum dots emit red light[4][1].
Quantum dots have a variety of functions including but not limited to fluorescent dyes, transistors, LEDs, solar cells, and medical imaging via optical probes[1][2].
One particularly important function of quantum dots is their use in lymph node mapping, which is feasible due to their unique ability to emit light in the near infrared (NIR) region. Lymph node mapping allows surgeons to track if and where cancerous cells exist[5].
The use of quantum dots for these functions is especially beneficial because quantum dots emit brighter light, they are excited by a wide variety of wavelengths, and they are more resistant to light than other substances[5][1].
- ^ a b c d e f g h Rice, C.V.; Griffin, G.A. (2008). "Simple Syntheses of CdSe Quantum Dots". Journal of Chemical Education. 85 (6): 842. Retrieved 5 November 2016.
- ^ a b c d e "Quantum Dots : a True "Particle in a Box" System". PhysicsOpenLab. 20 November 2015. Retrieved 5 November 2016.
- ^ a b c Overney, René M. "Quantum Confinement" (PDF). University of Washington. Retrieved 5 November 2016.
- ^ Zahn, Dietrich R.T. "Surface and Interface Properties of Semiconductor Quantum Dots by Raman Spectroscopy" (PDF). Technische Universität Chemnitz. Retrieved 5 November 2016.
- ^ a b Bentolila, Laurent A.; Ebenstein, Yuval (2009). "Quantum Dots for In Vivo Small-Animal Imaging". Journal of Nuclear Medicine. 50 (4): 493–496. Retrieved 5 November 2016.