Quantum dots can be defined as semiconductor nanostructures which are artificial in nature and ranges from 2-10 nm in size. These tiny nanocrystals become excited under illumination and emits colors of different wavelength. Quantum dots possess unique properties determined by their structure (hollow or solid), size, shape and composition. Fabrication of Quantum dots is achieved by several methods such as electron beam lithography, epitaxy or by means of colloidal synthesis.
Academic Editor: Muhammad Humayun, Huazhong University of Science and Technology, China.
Checked for plagiarism: Yes
Review by: Single-blind
Copyright © 2019 Nida Tabassum Khan, et al.
The authors have declared that no competing interests exist.
The word ‘Quantum’ itself is derived from a Latin word meaning ‘amount’ and can be defined as small unit of physical property like energy or matter 1. In 1900 physicist Max Planck discovered that like matter radiation existed in discrete units of energy, hence named these units as “quanta” 2. Similarly, quantum dots can be defined as semiconductor nanostructures which are artificial in nature and ranges from 2-10 nm in size 3, 4.These tiny nanocrystals become excited under illumination and emits colors of different wavelength 5. Quantum dots possess unique properties determined by their structure (hollow or solid), size, shape and composition 6.Sometimes these are also referred as artificial atoms 7. Quantum dots have different crystalline lattice structures so when pressure is applied they form very thin semiconductor films 8. As a result, the flat film later due to stress tends to separate into dots in three dimensions 9.
Physiochemical Properties of Quantum dots is mentioned in Table 1.Table 1. Physiochemical Properties of Quantum dots
|1||Size||Microscopic, 2-10nm (10-50 atoms) 10|
|2||Configuration||Confined in three-dimensions 11|
|3||Highly tunable||Variable core sizes make them give off different colors by tuning/changing the characteristic wavelength of emitted light 12.|
|4||Excitable||Can excite to higher energy level to emit light of respective wavelength 13|
|5||Shapes||Various including cubes, spheres and pyramids 14|
|6||Resistance||Resistance to photo-bleaching, photo-degradation and chemical- degradation 15, 16.|
Types of Quantum Dots
There are 3 types of Quantum dots on the basis of their composition and structure 17.
Core-Typed Quantum Dots
Core-shell Quantum Dots
Also known as Core-Shell semi-conducting nanoparticles having variable photophysical properties e.g ZnS20
Alloyed Quantum Dots
Multicomponent semiconductor nanoparticles e.g. CdS-Se/ZnS 21
Applications of Quantum Dots
Used in Solar cells and photo-voltaic e.g. Graphene quantum dots 26.
Used as fluorophores which helps in bio-sensing and bio-tagging 27.
Used as a catalyst to form hydrocarbons 28
Luminescent quantum dots (LQD) are used in high quality displays and lighting systems 29
Quantum computing uses quantum computer that store information in quantum bits 30.
Magnetic quantum particles are used in memory chips 31
Used in communication devices like lasers 32.
Have biological applications including in vivo and invitro imaging, DNA assays and microarrays,labelling tumors , diagnosis /treatment of cancer , drug delivery 33, 34, 35, 36
Quantum dots have many exceeding rewards, but they do have drawbacks like they are costly, toxic, may cause environmental pollution etc 37.
Due to their excellent intrinsic and extrinsic properties, Quantum dots continues to amaze researchers with their immense applications.
- 2.H S Mansur. (2010) Quantum dots and nanocomposites. , Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology 2(2), 113-129.
- 5.S A Empedocles, D J Norris, M G Bawendi. (1996) Photoluminescence spectroscopy of single CdSe nanocrystallite quantum dots. Physical review letters. 77(18), 3873.
- 7.Chakraborty T. (1992) Physics of the artificial atoms: Quantum dots in a magnetic field. , Comments Cond. Mat. Phys 16, 35-68.
- 8.W H Chang, W Y Chen, H S Chang, T P Hsieh, J I Chyi et al. (2006) Efficient single-photon sources based on low-density quantum dots in photonic-crystal nanocavities. Physical review letters. 96(11), 117401.
- 9.A M Smith, A M Mohs, Nie S. (2009) Tuning the optical and electronic properties of colloidal nanocrystals by lattice strain. , Nature nanotechnology 4(1), 56.
- 10.A P. (1996) Semiconductor clusters, nanocrystals, and quantum dots. , science 271(5251), 933-937.
- 11.Braskén M, Lindberg M, Sundholm D, Olsen J. (2000) Full configuration interaction calculations of electron-hole correlation effects in strain-induced quantum dots. , Physical Review B 61(11), 7652.
- 12.R J Warburton, B T Miller, C S Dürr, Bödefeld C, Karrai K et al. (1998) Coulomb interactions in small charge-tunable quantum dots: A simple model. , Physical Review B 58(24), 16221.
- 13.Goulding D, S P Hegarty, Rasskazov O, Melnik S, Hartnett M et al. (2007) Excitability in a quantum dot semiconductor laser with optical injection. Physical review letters. 98(15), 153903.
- 14.A F Sadreev, E N Bulgakov, Rotter I. (2006) Bound states in the continuum in open quantum billiards with a variable shape. Physical Review B. 73(23), 235342.
- 15.Sapsford K, Pons T, Medintz I, Mattoussi H. (2006) Biosensing with luminescent semiconductor quantum dots. , Sensors 6(8), 925-953.
- 16.S F Lee, M A Osborne. (2009) Brightening, blinking, bluing and bleaching in the life of a quantum dot: friend or foe?. , ChemPhysChem 10(13), 2174-2191.
- 17.Gleiter H. (2000) Nanostructured materials: basic concepts and microstructure. , Acta materialia 48(1), 1-29.
- 18.Kim S, Fisher B, H J Eisler, Bawendi M. (2003) Type-II quantum dots: CdTe/CdSe (core/shell) and CdSe/ZnTe (core/shell) heterostructures. , Journal of the American Chemical Society 125(38), 11466-11467.
- 19.M R Gao, Y F Xu, Jiang J, S H Yu. (2013) Nanostructured metal chalcogenides: synthesis, modification, and applications in energy conversion and storage devices. , Chemical Society Reviews 42(7), 2986-3017.
- 20.Zhou H, Alves H, D M Hofmann, Kriegseis W, B K Meyer et al. (2002) Behind the weak excitonic emission of ZnO quantum dots: ZnO/Zn (OH) 2 core-shell structure. , Applied Physics Letters 80(2), 210-212.
- 21.R E Bailey, Nie S. (2003) Alloyed semiconductor quantum dots: tuning the optical properties without changing the particle size. , Journal of the American Chemical Society 125(23), 7100-7106.
- 22.M H Werts, Lambert M, J P Bourgoin, Brust M. (2002) Nanometer scale patterning of Langmuir− Blodgett films of gold nanoparticles by electron beam lithography. , Nano Letters 2(1), 43-47.
- 23.Yin Y, A P. (2004) Colloidal nanocrystal synthesis and the organic–inorganic interface. , Nature 437(7059), 664.
- 24.R M Penner. (2000) Hybrid electrochemical/chemical synthesis of quantum dots. , Accounts of chemical research 33(2), 78-86.
- 25.Fontcuberta i Morral, Spirkoska A, Arbiol D, Heigoldt J, Morante M et al. (2008) Prismatic Quantum Heterostructures Synthesized on Molecular‐Beam Epitaxy GaAs Nanowires. , small 4(7), 899-903.
- 26.A J Nozik, M C Beard, J M Luther, Law M, R J Ellingson et al. (2010) Semiconductor quantum dots and quantum dot arrays and applications of multiple exciton generation to third-generation photovoltaic solar cells. , Chemical reviews 110(11), 6873-6890.
- 27.A R Clapp, I L Medintz, Mattoussi H. (2006) Förster resonance energy transfer investigations using quantum‐dot fluorophores. , ChemPhysChem 7(1), 47-57.
- 29.J M Costa-Fernández, Pereiro R, Sanz-Medel A. (2006) The use of luminescent quantum dots for optical sensing. , TrAC Trends in Analytical Chemistry 25(3), 207-218.
- 31.P A Maksym, Chakraborty T. (1990) Quantum dots in a magnetic field: Role of electron-electron interactions. , Physical Review Letters 65(1), 108.
- 32.Hakimi F, M G Bawendi, Tumminelli R, J R Haavisto. (1993) . U.S. Patent No. 5,260,957. Washington, DC: U.S. Patent and Trademark Office .
- 33.M P Bruchez, C Z Hotz. (2007) . Quantum dots: applications in biology,Springer Science and Business Media.(374) .
- 34.Chomoucka J, Drbohlavova J, Ryvolova M, Sobrova P, Janu L et al. (2012) Quantum dots: biological and biomedical application. Quantum dots: applications, synthesis and characterization. , New York
- 35.B H, V, F B Bayramov, Vasidev M, Dutta M et al. (2008) Semiconductors and Biomedical Structures for Nanobiometric Applications. In 14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics , Berlin, Heidelberg 594-597.
- 36.Chaudhary S, Umar A, K, Singh S. (2017) Applications of carbon dots in nanomedicine. , Journal of Biomedical Nanotechnology 13(6), 591-637.
Cited by (1)
- 1.Kausar Ayesha, 2021, Polymer dots and derived hybrid nanomaterials: A review, Journal of Plastic Film & Sheeting, 37(4), 510, 10.1177/87560879211010313