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Non-Coherent Photon...
Non-Coherent Photon Upconversion on Dye-Sensitized Nanostructured ZrO2 Films for Efficient Solar Light Harvesting
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- Lissau, Jonas Sandby, 1984- (författare)
- Uppsala universitet,Fysikalisk kemi
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- Morandeira, Ana, Dr. (preses)
- Uppsala universitet,Fysikalisk kemi
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- Gardner, James M., Dr. (preses)
- KTH
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- Hammarström, Leif, Prof. (preses)
- Uppsala universitet,Fysikalisk kemi
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- Michl, Josef, Professor (opponent)
- University of Colorado Boulder, USA/Academy of Sciences of the Czech Republic, Czech Republic
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(creator_code:org_t)
- ISBN 9789155490003
- Uppsala : Acta Universitatis Upsaliensis, 2014
- Engelska 125 s.
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Serie: Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 ; 1164
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Abstract
Ämnesord
Stäng
- Photon upconversion by sensitized triplet–triplet annihilation (UC-STTA) is a photophysical process that facilitates the conversion of two low-energy photons into a single high-energy photon. A low-energy photon is absorbed by a sensitizer molecule that produces a triplet excited state which is transferred to an emitter molecule. When two emitter triplet states encounter each other, TTA can take place to produce a singlet excited state which decays by emission of a high-energy (upconverted) photon. While traditional single-threshold dye-sensitized solar cells (DSSCs) have a maximum efficiency limit of ca. 30%, it has been predicted theoretically that implementation of UC-STTA in DSSCs could increase that efficiency to more than 40%.A possible way to implement UC-STTA into DSSCs, would be to replace the standard sensi- tized nanostructured TiO2 photoanodes by upconverting ones loaded with emitter molecules. Following TTA, the excited emitter molecule would be quenched by injection of a high-energy electron into the conduction band of the TiO2. To explore the practical aspects of this strategy for a highly efficient DSSC, in this thesis UC-STTA is studied in model systems based on nanostructured ZrO2 films. These ZrO2 films are a good proxy for the TiO2 films used in DSSCs, and allow for relatively easy optimization and study of UC-STTA by allowing measurements of the upconverted photons without the complications of electron injection into the film.Herein it is experimentally proven that UC-STTA is viable on nanostructured metal oxide films under non-coherent irradiation with intensities comparable to sunlight. Two different system architectures are studied, differing in the position of the molecular components involved in the UC-STTA mechanism. Both architectures have the emitter molecules adsorbed onto the ZrO2 surface, but the sensitizers are positioned either in solution around the nanostructure, or co-adsorbed with the emitters onto the ZrO2 surface. A set of challenges in the study and optimization of the UC-STTA process is identified for each type of system. Proposals are also given for how to further improve the understanding and UC-STTA optimization of these systems toward application in DSSCs to overcome the present solar energy conversion efficiency limit.
Ämnesord
- NATURVETENSKAP -- Kemi -- Fysikalisk kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Physical Chemistry (hsv//eng)
Nyckelord
- photon upconversion
- triplet-triplet annihilation
- DSSC
- dye-sensitized
- delayed fluorescence
- photophysics
- solar energy conversion
- nanostructured surface
- energy migration
- Kemi med inriktning mot kemisk fysik
- Chemistry with specialization in Chemical Physics
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- vet (ämneskategori)
- dok (ämneskategori)
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