Spectroscopic study of defects in cadmium selenide quantum dots (QDS) and cadmium selenide nanorods (NRS)

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dc.contributor.author Roy, Santanu
dc.date.accessioned 2013-08-02T14:13:44Z
dc.date.available 2013-08-02T14:13:44Z
dc.date.issued 2013-08-02
dc.identifier.uri http://hdl.handle.net/2097/16118
dc.description.abstract Ever depleting sources of fossil fuel has triggered more research in the field of alternate sources of energy. Over the past few years, CdSe nanoparticles have emerged as a material with a great potential for optoelectronic applications because of its easy exciton generation and charge separation. Electronic properties of CdSe nanoparticles are highly dependent on their size, shape and electronic environment. The main focus of this research is to explore the effect of different electronic environments on various spectroscopic properties of CdSe nanoparticles and link this to solar cell performance. To attain that goal, CdSe quantum dots (QDs) and nanorods (NRs) have been synthesized and either doped with metal dopants or embedded in polymer matrices. Electronic properties of these nanocomposites have been studied using several spectroscopic techniques such as absorption, photoluminescence, time-resolved photoluminescence, confocal microscopy and wide field microscopy. Indium and tin are the two metal dopants that have been used in the past to study the effect of doping on conductivity of CdSe QDs. Based on the photoluminescence quenching experiments, photoluminescence of both indium and tin doped samples suggest that they behave as n-type semiconductors. A comparison between theoretical and experimental data suggests that energy levels of indium doped and tin doped QDs are 280 meV and 100 meV lower than that of the lowest level of conduction band respectively. CdSe nanorods embedded in two different polymer matrices have been investigated using wide field fluorescence microscopy and confocal microscopy. The data reveals significant enhancement in bandedge luminescence of NRs in the vicinity of a conjugated polymer such as P3HT. Photoactive charge transfer from polymers to the surface traps of NRs may account for the observed behavior. Further study shows anti-correlation between bandedge and trap state emission of CdSe NRs. A recombination model has been proposed to explain the results. The origin of traps is also investigated and plausible explanations are drawn from the acquired data. en_US
dc.language.iso en_US en_US
dc.publisher Kansas State University en
dc.subject Spectroscopy of defects en_US
dc.title Spectroscopic study of defects in cadmium selenide quantum dots (QDS) and cadmium selenide nanorods (NRS) en_US
dc.type Dissertation en_US
dc.description.degree Doctor of Philosophy en_US
dc.description.level Doctoral en_US
dc.description.department Department of Chemistry en_US
dc.description.advisor Viktor Chikan en_US
dc.subject.umi Chemistry (0485) en_US
dc.date.published 2013 en_US
dc.date.graduationmonth August en_US

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