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dc.contributor.advisorBasu, Jaydeep Kumar
dc.contributor.authorMullapudi, Praveena
dc.date.accessioned2017-11-28T16:10:33Z
dc.date.accessioned2018-07-31T06:18:48Z
dc.date.available2017-11-28T16:10:33Z
dc.date.available2018-07-31T06:18:48Z
dc.date.issued2017-11-28
dc.date.submitted2016
dc.identifier.urihttps://etd.iisc.ac.in/handle/2005/2825
dc.identifier.abstracthttp://etd.iisc.ac.in/static/etd/abstracts/3675/G27878-Abs.pdfen_US
dc.description.abstractOver the last few decades, a vast research is going on, to study the optical properties of the nano particles i.e., metal and semiconductors thoroughly. Till date most of the optical studies are based on single particle measurement of a quantum dot (QD) or a chromophore under the influence of an external plasmonic field stimulus. In this the-sis, we tried to address the energy transfer at non local level on a layer of compact, monolayer QD assemblies over micro meter range. The energy transfer occurs in the presence of external field of metal particles or nanorods leads to the enhancement or quenching the emission from a layer of QDs. Chapter 1 is introduction to the basic theoretical aspects of excitons in semiconductor (QDs) and its optical properties under strong confinement regime. The discussion is followed with the optical properties of gold nanoparticles and rods, describing size and shape dependent variation of absorption properties, based on Mie and Mie-Gans theory. Theoretical background of collective effects in QD assemblies based on exciton-plasmonic interactions at single particle level as well as polarization based plasmo-nenhanced fluorescence has been subjected. Experimental techniques are explained in chapter 2 which contains the details of the synthesis of polymer capped nanoparticles with the respective characterization. A discussion on the synthesis methods for cadmium selenide QDs, gold nano particles and the rods with different polymer cap-ping legends and the related capping exchange methods. The thin film preparation of QD monolayers as well as hybrid nano assemblies using several techniques, i.e., Langmuir-Blodgett (LB), dip coat methods are provided. Further the details of surface morphology of the prepared thin films has been studied by different microscopic techniques i.e., atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The details of the PL emission measurements of these hybrid arrays using confocal, Raman and polarization based near field scanning optical microscope (NSOM) modes followed with the life time measurements. In third chapter, the substantial strong coupling and collective emission regime is engineered in the QD monolayer films embedded with tiny gold nano particles keeping the QD density same. Tuning the photoluminescence (PL) of semiconducting QD assemblies using small Au NPs in different ratio, different packing density and extent of spectral overlap between QD photoluminescence and the metal nanoparticle absorbance has been discussed. We provided possible experimental and theoretical evidence for the plasmon-mediated emergence of collective emission and enhanced quantum efficiency in these QD films with the consolidation of multiple emitters and multiple NPs. The quantum efficiency of these hybrid assemblies is further explored with different material as well as the size effect of metal nano particles. Chapter 4 comprises the experiment results of the self-assembled compact and partially aligned gold nano rod (GNR) arrays on QD monolayer films. We experimentally demonstrated the quantum efficiency of these QD hybrid assemblies is gaining max-imum when the longitudinal surface plasmon resonance (LSPR) absorption maxima of GNR arrays is resonant with the QD monolayer PL maxima and is always non-existent for the off resonant case. Further, we reported the variability in the size and morphology of these GNR domains leads to the maximum achieved enhancement as well as anisotropy value in comparison with isolated rods and the explored conditions to further enhance the efficiency in these QD hybrid assemblies.en_US
dc.language.isoen_USen_US
dc.relation.ispartofseriesG27878en_US
dc.subjectNanotechnologyen_US
dc.subjectMetal Nanoparticlesen_US
dc.subjectNanoassembliesen_US
dc.subjectSemiconductor Quantum Dotsen_US
dc.subjectExcitonsen_US
dc.subjectMetal Nanorodsen_US
dc.subjectGold Nano Rodsen_US
dc.subjectPolymer Capped Nanoparticlesen_US
dc.subjectCadmium Selenide Quantum Dotsen_US
dc.subjectPlasmonsen_US
dc.subjectQuantum Dot Arraysen_US
dc.subjectHybrid Nanoassembliesen_US
dc.subjectQuantum Dot Filmsen_US
dc.subjectQuantum Dot Monolayersen_US
dc.subjectQuantum Dot Assembliesen_US
dc.subjectQuantum Dotsen_US
dc.subject.classificationPhysicsen_US
dc.titleStudy of Optical Properties of Semiconductor Quantum Dot Based Hybrid Nano Assembliesen_US
dc.typeThesisen_US
dc.degree.namePhDen_US
dc.degree.levelDoctoralen_US
dc.degree.disciplineFaculty of Scienceen_US


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