Quantum dot-dye hybrid systems for energy transfer applications [Elektronische Ressource] / Ting Ren
171
pages
English
Documents
2010
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171
pages
English
Ebook
2010
Obtenez un accès à la bibliothèque pour le consulter en ligne En savoir plus
Publié par
Publié le
01 janvier 2010
Nombre de lectures
11
Langue
English
Poids de l'ouvrage
45 Mo
Publié par
Publié le
01 janvier 2010
Nombre de lectures
11
Langue
English
Poids de l'ouvrage
45 Mo
Quantum Dot-Dye Hybrid Systems
for Energy Transfer Applications
Dissertation
zur Erlangung des Grades
„Doktor der Naturwissenschaften“
In Promotionsfach Chemie
am Fachbereich Chemie, Pharamazie und Geowissenschaften
der Johannes Gutenberg-Universität Mainz
Ting Ren
geb. in Shanghai, P.R. China
Mainz, 2010
Table of Contents
1 Introduction............................................................................................................. 1
2 Theoretical background ......................................................................................... 6
2.1 Quantum dot properties .................................................................................... 6
2.1.1 Bulk semiconductors................................................................................. 6
2.1.2 Quantum dots............................................................................................ 7
2.1.3 Core-shell quantum dots ......................................................................... 11
2.2 Fluorescence resonance energy transfer ......................................................... 17
2.2.1 Characteristics of FRET.......................................................................... 17
2.2.2 Principles of FRET ................................................................................. 18
2.2.3 Measurement of FRET............................................................................ 20
2.3 Energy transfer with quantum dots................................................................. 23
2.3.1 Energy transfer between quantum dots................................................... 23
2.3.1.1 Energy transfer in thin solid film containing quantum dots ................23
2.3.1.2 Energy transfer in layered assemblies of quantum dots ......................24
2.3.1.3 Energy transfer in solution-based complexes containing quantum
dots.......................................................................................................26
2.3.2 Energy transfer from quantum dots to organic dye molecules ............... 27
2.3.2.1 Energy transfer in quantum dot-dye mixtures .....................................27
2.3.2.2 Energy transfer in polymer-mediated quantum dot-dye complexes....29
2.3.2.3 Energy transfer in biomolecule-mediated quantum dot-dye
complexes ............................................................................................30
2.3.3 Energy transfer from quantum dots to metal nanoparticles.................... 32
3 Materials and methods ......................................................................................... 34
3.1 Materials ......................................................................................................... 34
3.2 Synthesis methods........................................................................................... 38
3.2.1 CdSe/CdS/ZnS core-shell quantum dots................................................. 38
3.2.2 Quantum dot hybrid systems .................................................................. 40
3.2.2.1 Quantum dot - silica hybrids................................................................40
3.2.2.2 Quantum dot - silica - dye hybrids.......................................................... 42
3.2.2.3 Quantum dot - dye hybrids ..................................................................... 42
iii3.3 Characterization techniques ............................................................................44
3.3.1 Absorption spectroscopy.........................................................................44
3.3.2 Steady-state fluorescence spectroscopy ..................................................44
3.3.3 Transmission electron microscopy..........................................................45
3.3.4 Fluorescence lifetime spectroscopy ........................................................46
3.3.5 Dynamic light scattering .........................................................................46
Results and Discussion
4 Quantum dot - silica hybrid system.....................................................................48
4.1 Introduction .....................................................................................................48
4.2 Silica - quantum dot - silica architecture.........................................................50
4.2.1 Experimental procedure ..........................................................................50
4.2.2 Results and discussion.............................................................................51
4.2.2.1 TEM characterization.......................................................................... 51
4.2.2.2 Optical properties ................................................................................ 54
4.2.2.3 Influence of silica core size................................................................. 55
4.2.2.4 Thickness control ................................................................................ 57
4.3 Quantum dot - silica architecture: silica coated quantum dots........................59
4.3.1 Experimental procedure ..........................................................................59
4.3.2 Results and discussion.............................................................................60
4.3.2.1 TEM characterization.......................................................................... 60
4.3.2.2 Optical properties ................................................................................ 60
4.3.2.3 Growth process of QD-silica spheres.................................................. 61
4.3.2.4 Control of silica shell thickness .......................................................... 64
4.4 Conclusion.......................................................................................................72
5 Quantum dot - silica - dye hybrid system ...........................................................73
5.1 Introduction .....................................................................................................73
5.2 Experimental procedure ..................................................................................74
5.3 Results and discussion.....................................................................................77
5.3.1 TEM characterization..............................................................................77
5.3.1.1 CdSe/CdS/ZnS QDs ............................................................................ 78
5.3.1.2 Silica cores .......................................................................................... 78
5.3.1.3 Silica-dye (silica-core - dye-shell) nanospheres.................................. 78
5.3.1.4 QD-silica-dye hybrid nanoparticles .................................................... 78
iv 5.3.2 Fluorescence of silica-dye particles........................................................ 79
5.3.3 Fluorescence of QD-silica-dye particles................................................. 81
5.3.3.1 Optical properties of QD-silica-dye particles ......................................81
5.3.3.2 Monte-Carlo Simulations.....................................................................84
5.3.3.3 Experimental determination of the amount of QDs adsorbed onto
pure silica and onto silica-dye particles...............................................87
5.3.3.4 Attraction between QD and Texas Red molecules ..............................89
5.4 Conclusion ...................................................................................................... 91
6 Quantum dot - dye hybrid system....................................................................... 92
6.1 Introduction..................................................................................................... 92
6.2 Quantum dot - dye hybrids in non-aqueous solution...................................... 94
6.2.1 Experimental procedure.......................................................................... 94
6.2.2 Results and discussion ............................................................................ 95
6.2.2.1 Characterization of QD-dye complexes...............................................95
6.2.2.2 Study of binding mechanism and reaction conditions.........................98
6.2.2.3 Stability of QD-dye complexes..........................................................106
6.2.2.4 Energy transfer in QD-dye complexes...............................................108
6.2.2.5 Distance dependence of energy transfer in QD-dye complexes ........113
6.3 Quantum dot - dye hybrids in aqueous solution ........................................... 123
6.3.1 Experimental procedure........................................................................ 123
6.3.2 Results and discussion .......................................................................... 124
6.3.2.1 Phase transfer method........................................................................124
6.3.2.2 “Refluxing” method...........................................................................126
6.4 Quantum dot assemblies ............................................................................... 135
6.4.1 Experimental procedure......................................................
