Effect of progressive oxidation on the optical properties of small silicon quantum dots: A computational study

2008 ◽  
Vol 77 (24) ◽  
Author(s):  
R. J. Eyre ◽  
J. P. Goss ◽  
P. R. Briddon
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Computational Study ◽  
Silicon Quantum Dots

scholarly journals Synthesis, Surface Modification and Purification of Silicon and Germanium Quantum Dots for Biological Applications

2021 ◽  
Author(s):  
◽  
Amane Shiohara
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Silica Nanoparticles ◽  
Microemulsion System ◽  
Biological Applications ◽  
Silicon Quantum Dots ◽  
Surface Molecules ◽  
Silicon And Germanium ◽  
Germanium Quantum Dots ◽  
Oxygen Atoms

<p>Quantum dots have applications in biomedical fields such as bio-imaging and drug delivery systems. This thesis describes research on silicon and germanium nanoparticles (quantum dots) synthesis and surface modification for biological applications. Purification methods of these quantum dots were also explored. In chapter 6 the application of silica nanoparticles into dry eye diagnosis was studied. The purpose of this research is to contribute the application of nanotechnology into biological fields. The crystalinity of the quantum dots was characterised by Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction analysis (SAED). The molecules on the surface of the quantum dots were characterised by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR).  Silicon quantum dots were synthesised with a microemulsion system and various types of molecules were attached on the surface of the silicon quantum dots. However, some of the capping molecules which have oxygen atoms tend to form bonds between oxygen and silicon. Therefore, in the later chapter (chapter 4) various chemical reactions were conducted on the molecules attached to the silicon quantum dots. The silicon quantum dots were capped with diene molecules and one of the double bonds was left on the terminal end. The terminal end double bonds were converted to the functional groups which contain oxygen atoms to form peptide bonds. In this way it was confirmed that it can reduce the risk of oxygen atoms to be attached on the surface of the silicon quantum dots. The molecules on the surface of the silicon quantum dots were characterised mainly by FTIR and ¹H NMR. Optical properties and cyto-toxicity of these silicon quantum dots were also measured and analysed depending on the surface molecules.  Two synthetic approaches were taken to produce germanium quantum dots. The first approach was the microemulsion system at room temperature. Different combinations of the surfactant and capping molecules were tested. For the second approach, high temperature bench top system was applied. In this method the bio-friendly molecules which have high boiling points were chosen as capping agents. The surface molecules were characterised by FTIR spectroscopy.  In chapter 6 the synthesis of dye molecules conjugated silica nanoparticles was described. The purpose of this research is to produce biologically safe nanoparticles which can be applied in dry eye diagnosis. Three different dyes were used to conjugate with the silica nanoparticles. Only fluorescein isothiocyanate (FITC) succeeded in conjugating with the nanoparticles. Optical properties of this sample were measured and compared with the free dye molecule. Also the sample was applied in human eyes to analyse the tear film layer.  An overall conclusion and future plans for the research were given in the last chapter.In this chapter, ideas of overcoming the problems and improving the techniques conducted in the research were described.</p>

scholarly journals Tuning the Optical Properties of Silicon Quantum Dots via Surface Functionalization with Conjugated Aromatic Fluorophores

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohammed Abdelhameed ◽  
Diego Rota Martir ◽  
Shalimar Chen ◽  
William Z. Xu ◽  
Olabode O. Oyeneye ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Surface Functionalization ◽  
Silicon Quantum Dots

Structural and optical properties of silicon quantum dots in silicon nitride grown in situ by PECVD using different gas precursors

2009 ◽  
Vol 159-160 ◽  
pp. 74-76 ◽  
Author(s):  
Lucia V. Mercaldo ◽  
Paola Delli Veneri ◽  
Emilia Esposito ◽  
Ettore Massera ◽  
Iurie Usatii ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Silicon Nitride ◽  
Structural And Optical Properties ◽  
Silicon Quantum Dots

scholarly journals Optical properties of amorphous silicon quantum dots (a-Si QDs) with various dot size using extended Hückel theory

2013 ◽  
Author(s):  
Setianto ◽  
Liu Kin Men ◽  
Ferry Faizal ◽  
Bambang Mukti Wibawa ◽  
Doy Hardoyo Hardjo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Amorphous Silicon ◽  
Silicon Quantum Dots

scholarly journals Synthesis, Surface Modification and Purification of Silicon and Germanium Quantum Dots for Biological Applications

2021 ◽  
Author(s):  
◽  
Amane Shiohara
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Silica Nanoparticles ◽  
Microemulsion System ◽  
Biological Applications ◽  
Silicon Quantum Dots ◽  
Surface Molecules ◽  
Silicon And Germanium ◽  
Germanium Quantum Dots ◽  
Oxygen Atoms

<p>Quantum dots have applications in biomedical fields such as bio-imaging and drug delivery systems. This thesis describes research on silicon and germanium nanoparticles (quantum dots) synthesis and surface modification for biological applications. Purification methods of these quantum dots were also explored. In chapter 6 the application of silica nanoparticles into dry eye diagnosis was studied. The purpose of this research is to contribute the application of nanotechnology into biological fields. The crystalinity of the quantum dots was characterised by Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction analysis (SAED). The molecules on the surface of the quantum dots were characterised by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR).  Silicon quantum dots were synthesised with a microemulsion system and various types of molecules were attached on the surface of the silicon quantum dots. However, some of the capping molecules which have oxygen atoms tend to form bonds between oxygen and silicon. Therefore, in the later chapter (chapter 4) various chemical reactions were conducted on the molecules attached to the silicon quantum dots. The silicon quantum dots were capped with diene molecules and one of the double bonds was left on the terminal end. The terminal end double bonds were converted to the functional groups which contain oxygen atoms to form peptide bonds. In this way it was confirmed that it can reduce the risk of oxygen atoms to be attached on the surface of the silicon quantum dots. The molecules on the surface of the silicon quantum dots were characterised mainly by FTIR and ¹H NMR. Optical properties and cyto-toxicity of these silicon quantum dots were also measured and analysed depending on the surface molecules.  Two synthetic approaches were taken to produce germanium quantum dots. The first approach was the microemulsion system at room temperature. Different combinations of the surfactant and capping molecules were tested. For the second approach, high temperature bench top system was applied. In this method the bio-friendly molecules which have high boiling points were chosen as capping agents. The surface molecules were characterised by FTIR spectroscopy.  In chapter 6 the synthesis of dye molecules conjugated silica nanoparticles was described. The purpose of this research is to produce biologically safe nanoparticles which can be applied in dry eye diagnosis. Three different dyes were used to conjugate with the silica nanoparticles. Only fluorescein isothiocyanate (FITC) succeeded in conjugating with the nanoparticles. Optical properties of this sample were measured and compared with the free dye molecule. Also the sample was applied in human eyes to analyse the tear film layer.  An overall conclusion and future plans for the research were given in the last chapter.In this chapter, ideas of overcoming the problems and improving the techniques conducted in the research were described.</p>

Optical Properties of Doped Silicon Quantum Dots with Crystalline and Amorphous Structures

2011 ◽  
Vol 115 (40) ◽  
pp. 19529-19537 ◽  
Author(s):  
Michael G. Mavros ◽  
David A. Micha ◽  
Dmitri S. Kilin
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Silicon Quantum Dots ◽  
Doped Silicon ◽  
Amorphous Structures

scholarly journals Energy/Electron Transfer Switch for Controlling Optical Properties of Silicon Quantum Dots

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohammed Abdelhameed ◽  
Shawkat Aly ◽  
Jeremy T. Lant ◽  
Xiaoran Zhang ◽  
Paul Charpentier
Keyword(s):  
Quantum Dots ◽  
Electron Transfer ◽  
Optical Properties ◽  
Energy Electron ◽  
Silicon Quantum Dots
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