Zinc Oxide Quantum Dots: Applications and Properties

This assignment delves into the fascinating world of zinc oxide quantum dots, focusing on their characterization, synthesis techniques, mechanical properties, and a wide range of applications. It examines their roles in bioimaging, gene therapy, drug delivery, and cancer therapy, highlighting the advantages and limitations of these nanoparticles.

Running head: NANOTECHNOLOGY 0
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Introduction
Several arenas of science and engineering have embraced the employment of
nanotechnology. It will hence suggest that the dimensions of the material should be significantly
reduced, and this impacts the physical properties of chemical and mechanical (Chalsea, 2012).
This study paper will mostly be concentrated on nanoparticle technology of zinc oxide. As will
be discussed below, this report focuses on the history of zinc oxide quantum dots. Its synthesis,
advantages, and disadvantages.
History of zinc oxide quantum dots
Zinc Oxide Quantum Dots incorporate of zinc oxide particles that are covered with
groups of -COOH and –OH groups. They are hydrophilic Nano crystals which have a radiation
wavelength estimated at 555nm (Chopra, 2014). The quantum dots do not encompass any
pollutant, their elements are accessible in great volumes, for example, Cobalt and Lanthanum-
doped ZnO. In addition, the zinc oxide quantum dots are categorized by their nature of X-ray
powder diffraction, energy dispersive X-ray analysis, and the high-resolution transmission
electron microscopy. These doped elements exhibit an electromagnetic behavior at room
temperature. In addition, these quantum dots have the possibility of making the BGC 803 cells
effectively within a very short duration with no elements of toxicity or adversarial effects on the
growth of cell even at high concentrations (Ebessen, 2013).
Structure and synthesis of zinc oxide quantum dots
The structure occurs in dissimilar structures of zinc oxide nanoparticles and they are synthesized
using different techniques. These techniques can either group as either physical, biological or
chemical synthesis however, the structures can be grouped depending on the dimension of the
nanoparticles (Etching, 2014). They can either be a one-dimensional nanoparticle, two-
dimensional nanoparticle or even three-dimensional nanoparticle. The diagram below shows the
structure two-dimensional nanoparticle orientation of the nanotechnology (Francisa, 2013).

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Fig: Showing the two dimension of zinc oxide nanotechnology. ( chopra K , 2014)
Analysis of Chemical aspect
These type of synthesis is chemically achieved and can further be divided into either liquid or
gas synthesis.
Gas phase synthesis
This is as well-known as vacuum synthesis techniques are either achieved through gas
condensation method or through pyrolysis (Humain, 2014). Pyrolysis is whereby the flame
heating is used to generate aerosol droplets from the zinc salt and then dispersed into gas thereby
reducing their size. After which it is exposed to condensation and sintering.
Liquid phase synthesis
Liquid phase synthesis comprises methods such as synthesis, colloidal aspects, hydrothermal
synthesis, and co- synthesis among others. In this practice, a liquid agent is always reacted with
the zinc oxide nanoparticles. This will result to a particle which can be soluble or insoluble is
washed and heated at different temperatures to come up with the differently desired
nanoparticles (Jiyang, 2015).
Analysis of Physical phase synthesis
There are also different techniques entailed in this aspect including physical vapour deposition,
squatter deposition, ion implantation, ball milling among other methods. The production rates of
the zinc nanoparticles are always increased thereby appropriate for industrial applications. The

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ball milling process has been proved to be simple and effective and efficient since they only
involve the placing of a powdered material inside a ball mill and then passing balls containing
the high energy of collisions (james, 2014).
Analysis of Biological synthesis phase
Better known as the green synthesis of the nanoparticles produces the least amount of pollutants.
This technique is cheap and efficient enough and uses a variety of microorganisms during the
synthesis i.e. Fungi, virus and algae are used in the synthesis process. The methods used in the
biological synthesis includes (Nyangau, 2014).
Plant-mediated synthesis – this technology encompasses the usage of plant extracts to either act
as reducing or capping agents. It is very simple and applies the vivo and vitro mechanisms, but
they are only limited to some materials.
Microorganism mediated synthesis – usually in this techniques, the eco-friendly microbes are
employed and can either be extracellular or intracellular synthesis. It is one of the
recommendation techniques due to its non-pollutant nature and thus is widely applied in the
fields of bioleaching, Biomineralization and also bioremediation.
Characterization of zinc oxide quantum dots
Zinc oxide nanoparticles can either be characterized as a solar cell, photoluminescence or
absorption. The photoluminescence characterization involves the application of an excitation
with a certain dimension of the light wavelength to determine the luminesce characteristics. The
absorption characterization involves the use of a spectrometer device to determine the absorption
extent of the nanoparticles (James, 2013).
Mechanical properties of zinc oxide quantum dots
Some of the mechanical properties of the zinc oxide quantum dots includes the following
 The addition of zinc oxide particles also increases the storage modulus due to increased
aggregation.
 They have a high ultraviolet light absorption properties due to the wide band gap
 Zinc oxide particles have a good dispersion stability.
 The zinc oxide nanoparticles also have a high ultraviolet light resistance.

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 Tensile strength – zinc oxide particles have better tensile strength properties at a
relatively lower concentration, but at higher concentration the tensile strength reduces.
Advantages of this technology
These zinc oxide nanoparticles have many advantages in terms of health aspects to human.
Below are some of the advantages
 The zinc oxide nanoparticles have a property of green luminescence thus significant
agents during bioimaging.
 Because of its sunscreen efficiency, these nanoparticles are useful during situations of
knee or ligament injury as they will be able to adequately scatter light and encourage the
desired whitening (Chalsea, 2012).
 The zinc oxide dots also have a good texture and desirable spreadability thus they are
advantageous in promoting cosmetics
Disadvantages of this technology
 When the zinc oxide nanoparticles are used at a higher concentration, it can be toxic to
the human body.
 During the chemical synthesis of the nanoparticles, there are environmental pollutants
that are always produced which are harmful to the plant and human health.
 During the synthesis of zinc oxide, some of the reducing agents if not properly taken
care of may cause serious skin burns or any other form of injury an examples hydrazine.
Environmental impacts
Some of the environmental impacts of this technology is discussed below;
Stabilizers, surfactants and Capping agents- studies show that chemical synthesis involves the
wide application of these agents. Prior to their selection, there are factors that should be keenly
considered. These factors include the choice of the solvent, nontoxicity and the use of an
environmentally friendly agent
On Sonication –this process generally uses sound energy or ultrasonic means for the production
of nanoparticles. Usually, they employ up to 20 kHz frequency and this may cause permanent
hearing impairment if not properly taken off (Nyangau, 2014).

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Temperature – most of the synthesis techniques that involve the use of a high amount of heat
may seriously cause an imbalance of the earth’s overall temperature. Besides, these high
temperatures may result in heat stroke, heat rashes or even heat syncope.
Applications of zinc oxide nanoparticles
Zinc oxide nanotechnology has several applications in several fields as discussed below;
Bioimaging; as a result of the efficient epitomic blue and near ultraviolet emission from the zinc
nanoparticles, they are appropriate for the bioimaging application. Moreover, the intrinsic
fluorescence and the desired optical properties of the nanoparticles makes it possible for the
penetration of the human skin (james, 2014).
Drug delivery -The versatile nature, phototoxic effect and the large surface area of the zinc oxide
quantum particles allow for east delivery of the drug.
Biosensors -The biosensors including piezoelectric, calorimetric and others have been broadly
applied in the food industry, environmental monitoring and also health care. The development of
biosensors that are effective, efficient and have high performance is thus significant in these
applications (Etching, 2014). Research shows that the involvement of these zinc oxide
nanoparticles significantly helps to bring some desirable characteristics that help in achieving the
above requirement
Cancer therapy –apart from other applications, the zinc oxide nanoparticles due to their optical
properties and other characteristics find their application in the cancer therapy (James, 2013).
Conclusion
In conclusion one of the nanomaterial in terms of some aspects such as the characterization,
synthesis techniques, mechanical properties, history and then the various fields of applications
and its advantages and the limitations. Zinc oxide quantum dots was chosen as the topic of
research and the various applications have been described above. There are very many areas in
the nanotechnology sector where the zinc oxide particles are used. For instance bioimaging, gene
therapy, drug delivery and cancer therapy.

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References
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Chopra, K. (2014). Thin Film Devices . Washington : Springer science .
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Ebessen, W. (2013). Carbon Nanotubes. London : CRC press.
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Etching, P. (2014). Plasma sources for thin film Deposition . Manchester : Elsevier .
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