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dc.contributor.authorKang, Ji-Hwanen_US
dc.date.accessioned2013-01-17T21:46:38Z
dc.date.available2013-01-17T21:46:38Z
dc.date.issued2012-10-02en_US
dc.identifier.urihttp://hdl.handle.net/1853/45846
dc.description.abstractPhoton energy upconversion (UC), a process that can convert two or more photons with low energy to a single photon of higher energy, has the potential for overcoming the thermodynamic efficiency limits of sunlight-powered devices and processes. An attractive route to lowering the incident power density for UC lies in harnessing energy transfer through triplet-triplet annihilation (TTA). To maximize energy migration in multicomponent TTA-assisted UC systems, triplet exciton diffusivity of the chromophores within an inert medium is of paramount importance, especially in a solid-state matrix for practical device integration. In this thesis, low-threshold sensitized UC systems were fabricated and demonstrated by a photo-induced interfacial polymerization within a coaxial-flow microfluidic channel and in combination with nanostructured optical semiconductors. Dual-phase structured uniform UC capsules allow for the highly efficient bimolecular interactions required for TTA-based upconversion, as well as mechanical strength for integrity and stability. Through controlled interfacial photopolymerization, diffusive energy transfer-driven photoluminescence in a bi-molecular UC system was explored with concomitant tuning of the capsule properties. We believe that this core-shell structure has significance not only for enabling promising applications in photovoltaic devices and photochromic displays, but also for providing a useful platform for photocatalytic and photosensor units. Furthermore, for improving photon upconverted emission, a photonic crystal was integrated as an optical structure consisting of monodisperse inorganic colloidal nanoparticles and polymer resin. The constructively enhanced reflected light allows for the reuse of solar photons over a broad spectrum, resulting in an increase in the power conversion efficiency of a dye-sensitized solar cell as much as 15-20 %.en_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectUpconversionen_US
dc.subjectTriplet-triplet annihilationen_US
dc.subjectPhotochemistryen_US
dc.subjectEncapsulationen_US
dc.subjectLuminescenceen_US
dc.subject.lcshSolar energy
dc.subject.lcshPhotopolymerization
dc.titleEnergy transfer enhancement of photon upconversion systems for solar energy harvestingen_US
dc.typeThesisen_US
dc.description.degreeMSen_US
dc.contributor.departmentChemical Engineeringen_US
dc.description.advisorCommittee Chair: Reichmanis, Elsa; Committee Member: Hess, Dennis W.; Committee Member: Koros, William J.en_US


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