The document discusses quantum dots, engineered nanoparticles that have applications in various fields like computing, biology, and photovoltaics, due to their tunable properties. Despite their potential, quantum dots pose environmental and health risks, including cytotoxic and phytotoxic effects. The conclusion emphasizes the need for careful consideration of their toxicity and biological fate in practical applications.

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2. 4th National Conference on “Recent Advances in Engineering Technology and
Environmental issues (RAETE)”
J.C.D.M.College of Engineering,Sirsa
A WRONG TURN BY QUANTUM DOTS
RESULTED TOXICITY
AMIT SINGH B.Pharmacy(final year)
Bharat Bhushan Assistant Professor(JCDM College of Pharmacy)
Jagdish Chander Associate Professor(JCDM College of Engg.)
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Thursday, Feb23, 2012

3. Introduction
 Quantum Dots (QDs), a heterogeneous class of
engineered nanoparticles that are both semiconductors
and fluorophores, are rapidly emerging as an important
class of nanoparticles with numerous potential
applications ranging from medicine to energy.
 Basic structure of QD are nanocrystals composed of a
semiconductor core encased within a shell comprised of
a second semiconductor material.
 A typical QD has a diameter in the range of 2–10
nm, which is comparable with the size of a large protein.
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5. Applications of Quantum Dots
The ability to tune the size of quantum dots is advantageous for many applications. For instance, larger
quantum dots have a greater spectrum-shift towards red compared to smaller dots, and exhibit less
pronounced quantum properties. Conversely, the smaller particles allow one to take advantage of more subtle
quantum effects.
Computing
Biology
Photovoltaic
devices
Light emitting
devices
Photodetector
devices
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6. 
COMPUTING
Quantum dot technology is one of the most promising candidates for use
in solid-state quantum computation. By applying small voltages to the
leads, the flow of electrons through the quantum dot can be controlled
and thereby precise measurements of the spin and other properties
therein can be made. With several entangled quantum dots, or
qubits, plus a way of performing operations, quantum calculations and
the computers that would perform them might be possible.
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7. Biology
 Semiconductor quantum dots have also been employed for in vitro
imaging of pre-labelled cells. The ability to image single-cell
migration in real time is expected to be important to several research
areas such as embryogenesis, cancer metastasis,stem-cell
therapeutics, and lymphocyte immunology.
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8.  Photovoltaic effect:
• p-n Junction.
• Sunlight excites electrons
and creates electron-hole
pairs.
• Electrons concentrate on
one side of the cell and
holes on the other side.
• Connecting the 2 sides
creates electricity.
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9. Light emitting devices
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 Quantum dots are valued for displays, because they emit light in very specific
Gaussian distributions. This can result in a display that more accurately
renders the colours that the human eye can perceive. Quantum dots also
require very little power since they are not colour filtered. Additionally, since
the discovery of "white-light emitting" QD, general solid-state lighting
applications appear closer than ever. A colour liquid crystal display (LCD), for
example, is usually powered by a single fluorescent lamp (or
occasionally, conventional white LEDs) that is colour filtered to produce
red, green, and blue pixels. Displays that intrinsically produce monochromatic
light can be more efficient, since more of the light produced reaches the eye.

10. PHOTODETECTOR DEVICES
 Quantum dot photodetectors (QDPs) can be fabricated either via
solution-processing, or from conventional single-crystalline
semiconductors. Conventional single-crystalline semiconductor QDPs
are precluded from integration with flexible organic electronics due to the
incompatibility of their growth conditions with the process windows
required by organic semiconductors. On the other hand, solution-
processed QDPs can be readily integrated with an almost infinite variety
of substrates, and also post processed atop other integrated circuits.
Such colloidalQDPs have potential applications in surveillance, machine
vision, industrial inspection, spectroscopy.
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11.  Besides the above said positive features of Quantum dots, their internal structure
have several disadvantages which lead them to wrong path both inside the
human and in external environment.
Cytotoxic Effect
• Phytotoxicity
Environmental
• Marine
Toxicity Toxicity
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12. A Road to Wrong Path
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13. Conclusion
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