Quantum dots were discovered in 1980 by Russian physicist Alexei Ekimov and independently in 1982 by American chemist Louis E. Brus. They shared the Optical Society of America's 2006 R.W. Wood Prize for their pioneering work on quantum dots. Quantum dots are semiconductor nanoparticles that can emit light of various colors depending on their size. They have applications in LEDs, solar cells, photodetectors, biological labeling, and quantum computing due to their tunable light emission and other optical properties. Future areas of research include using quantum dots for cancer treatment, biological sensing, solid state quantum computing, and developing higher capacity quantum dot batteries.

1. AMMAD NASEEM
number: 03411923776
semester: second

7. Quantum dots were discovered in solids (glass crystals)
in 1980 by Russian physicist Alexei Ekimov while
working at the Vavilov State Optical Institute. In late
1982, American chemist Louis E. Brus, then working at
Bell Laboratories (and now a professor at Columbia
University), discovered the same phenomenon in
colloidal solutions (where small particles of one
substance are dispersed throughout another; milk is a
familiar example). These two scientists shared the
Optical Society of America's 2006 R.W. Wood Prize for
their pioneering work.
HISTORY OF QUANTUM DOTS

8. WHAT IS QUANTUM DOTS

9.  Nano mean any thing dimension is equal 10-9.(nanometer
is one thousand millionth of a meter).
 To understand how small one nm is let us see few
comparisons:
1. A Red Blood Cell is approximately 7000nm wide.
2. Water molecule is almost 0.3nm across.
3. Human hair which is about 80,000nm width.

10. WHAT IS QUANTUM DOTS

11. Shell :
An energy band in which electrons orbit the nucleus
of an atom..
Ligands :
An ion or neutral molecules which are attached to
central atom or ion are called ligands..
Core:
The central part of any thing, or fleshy fruit, containing the
seeds
WHAT IS QUANTUM DOTS

12. EXAMPLES OF QUANTUM DOTS
Cdse=cadmium
selenide
Cds=cadmium
sulfide
Znse= zinc selenide
Zns = zinc sulfide
Znc = zinc oxide

13. Cdse=cadmium selenide
EXAMPLES OF QUANTUM DOTS
Silicon

14. FORMATION OF QUANTUM DOTS

15. FORMATION OF QUANTUM DOTS
QD Synthesis: Colloidal Methods
J
Example: CdSe quantum dots
 30mg of Elemental Se and 5mL of octadecene are used
to create a stock precursor(a person or thing that comes
before another of the same kind) Se solution.
 0.4mL of Trioctylphosphine oxide (TOPO) is added to
the Se precursor solution to disassociate and cap the
Se.
 Separately, 13mg of CdO, 0.6mL of oleic acid and 10mL
of octadecene were combined and heated to 225oC .
 Once the CdO solution reaches 225oC, room-
temperature Se precursor solution was added.
 Varying the amount of Se solution added to the CdO
solution will result in different sized QDs.

16. Oleic acid is a fatty acid that occurs
naturally in various animal and vegetable
fats and oils. It is an odorless, colorless oil,
although commercial samples may be
yellowish. In chemical terms, oleic acid is
classified as a monounsaturated omega-9
fatty acid, abbreviated with a lipid number
of 18:1 cis-9
Octadecene is a long-chain hydrocarbon
and an alkene with the molecular formula
C18H36. There are multiple structural
isomers of octadecene, depending on the
position of the double bond. 1-
Octadecene, an alpha-olefin, is a relatively
inexpensive solvent, with a boiling point of
315 °C. It is compatible with oleic acid
FORMATION OF QUANTUM DOTS

17. OPTICAL PROPERTIES OF QUANTUM DOTS

18. COLOR CONTROL BY QD PARTICLE SIZE

19. OPTICAL PROPERTIES OF QUANTUM DOTS
• Photostability :resistant to change under the influence of radiant
energy and especially of light.

20. QUANTUM DOT SIZE AND COLOR

21. OPTICAL PROPERTIES OF QUANTUM DOTS

23. APPLICATIONS OF QUANTUM DOTS
 Quantum dots can emit any color of light from the same material by
changing the dot size.
 They have bright, pure colors along that can emit a rainbow of colors
coupled with their high efficiencies, longer lifetimes and high extinction.
 The high extinction coefficient of a quantum dot makes it perfect for
optical uses.
 Quantum dots of very high quality can be ideal for applications in optical
encoding and multiplexing due to their narrow emission spectra and
wide excitation profiles.
 Examples of optical applications of quantum dots include light emitting
diodes (LEDs),photodetectors, photovoltaics , quantum computing.

24. APPLICATIONS OF QUANTUM DOTS

25. OPTICAL APPLICATIONS OF QUANTUM DOTS
Light Emitting Diodes
 The advantage of QLED TV that
are use quantum dot color filter
and are capable of significantly
higher brightness than normal
LED.
 QD-LED displays can
render(give) colors very
accurately and use much less
power than traditional displays.

28. OPTICAL APPLICATIONS OF QUANTUM DOTS
Photodetectors

29. OPTICAL APPLICATIONS OF QUANTUM DOTS
Photodetectors

30. OPTICAL APPLICATIONS OF QUANTUM DOT
Solar cell
Traditional solar cell are made of semi-
conductors and expensive to produce .
Theoretical upper limit is 33% efficiency for
conversion 0f sunlight to electricity for
these cell.
Utilizing quantum dots allows realization of
third-generation solar cells at ~60%
efficiency in electricity production while
$100 or less per square meter of paneling
necessary.
Effective due to quantum dots ‘ ability to
preferentially absorb and emit radiation
that result in optimal generation of electric
current and voltage.

31. Quantum dots could make solar panels more efficient

32. OPTICAL APPLICATIONS OF QUANTUM DOTS
 Quantum dots have made up the way for
powerful ‘supercomputers’ known as
quantum computers.
 Quantum computers operate and store
information using quantum bits or
‘qubits(unit of quantum information)’, which
can exist in two states – both on and off
simultaneously.
 This remarkable phenomenon enables
information processing speeds and memory
capacity to both be greatly improved when
compared to conventional computers.
Quantum Computing

33. OPTICAL APPLICATIONS OF QUANTUM DOTS
Quantum Computing

35. OPTICAL APPLICATIONS OF QUANTUM DOTS
Biological Applications
 Quantum dots are also finding important medical
applications, including potential cancer treatments.
 Dots can be designed so they accumulate in particular parts
of the body and then deliver anti-cancer drugs bound to
them.
 Their big advantage is that they can be targeted at single
organs, such as the liver, much more precisely than
conventional drugs, so reducing the unpleasant side effects .
 Quantum dots are also being used in place of organic dyes
in biological research; for example, they can be used like
nanoscopic light bulbs to light up and color specific cells that
need to be studied under a microscope.
 They're also being tested as sensors for chemical and
biological warfare agents such as anthrax.
 Unlike organic dyes, which operate over a limited range of
colors and degrade relatively quickly, quantum dyes are very
bright, can be made to produce any color of visible light, and
theoretically last indefinitely (they are said to be photostable)
organic dyes
Anthrax
Nanoscopic light bulbs

36. Biological Applications

37. FUTURE WORK OF QUANTUM DOTS

38. THE FUTURE OF QUANTUM DOTS
 The excellent optical and transport properties, which are currently being studied for potential uses in
amplifiers, biological sensors and diode lasers.
 The broad range of real-time applications of quantum dots in the field of biology is expected to be very
useful in many research disciplines such as cancer metastasis.
 In the future researchers also believe that quantum dots can be used as the inorganic fluorophore in
intra-operative tumor detection when performed using fluorescence spectroscopy.
 In September previous year, Osaka University fabricated the first nanoelectric device that detects single
electron events in a target quantum dot, using a second dot as a sensor. The device was made using
two indium arsenide (InAs) quantum dots that were connected to electrodes narrowed to minimize any
undesirable screening effects. The discovery is important due to the ability to achieve electrical readout
of single electron states and combining the, with photonics for quantum communications.
 When compared to the organic luminescent materials used in organic light emitting diodes (OLEDs),
quantum dot based materials have a longer lifetime, purer colors, longer power consumption and a
lower manufacturing cost.
 A company called Store Dot is also using quantum dot technology to assemble a new battery. The new
battery can charge a phone from flat to full battery in less than one minute. The quantum dots used are
peptides modified to contain optical properties that can generate charge. The battery uses a quantum
dot nanocrystal instead of the traditionally used electrolytes.

39. FUTURE WORK OF QUANTUM DOTS

40. FUTURE WORK OF QUANTUM DOTS