Sökning: "triplet state"

Visar resultat 11 - 15 av 77 avhandlingar innehållade orden triplet state.

1. 11. Excited State Processes in Solar Energy Materials

   Författare :Tomas Österman; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar cells; Conjugated polymers; Charge transfer state; Time-resolved spectroscopy; Fluorescence; Artificial Photosynthesis; Bis-tridentate ruthenium II -complexes; Density functional theory; Quantum chemistry.;

   Sammanfattning : This dissertation covers studies of excited state processes in two types of solar energy materials: alternating polyfluorene polymers and their blends with fullerenes in the active layer of plastic solar cells, and bis-tridentate RuII-polypyridyl complexes to be used as sensitizer in systems for artificial photosynthesis. The polymer:fullerene blends were studied by transient absorption and time-resolved fluorescence measurements in order to investigate the role of the charge transfer (CT) state in charge formation. LÄS MER

3. 12. Experimental and Theoretical Studies of Cis-Trans Photoisomerizations and Conditions for Effective Catalysis

   Författare :Helene Möllerstedt; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; catalysis; triplet state; quantum chain process; cis-trans isomerization; adiabatic; potential energy surface; density functional theory; energy transfer;

   Sammanfattning : Triplet-sensitized cis-trans photoisomerizations have been investigated both experimentally and theoretically. Mapping of the reaction path for isomerization of 1,4-bis(1-propenyl)benzene (1) on the triplet state energy surface has been done by quantum yield measurements and laser flash photolysis. LÄS MER

4. 13. Photo-induced dark states influorescence spectroscopy – investigations & applications

   Författare :Andriy Chmyrov; Jerker Widengren; Johan Hofkens; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fluorescence correlation spectroscopy; triplet state; isomerisation; photobleaching; quenching; diffusion; total internal reflection; interface; Spectroscopy; Spektroskopi;

   Sammanfattning : This thesis focuses on investigations of transient dark states of fluorescentmolecules using spectroscopic techniques. The main purpose is to show andconvince the reader that transient dark states are not always a nuisance, butalso represent an additional source of information. LÄS MER

5. 14. Quantum Chemical Modeling of Dye-Sensitized Titanium Dioxide : Ruthenium Polypyridyl and Perylene Dyes, TiO2 Nanoparticles, and Their Interfaces

   Författare :Maria J. Lundqvist; Sten Lunell; Petter Persson; Lars Ojamäe; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; density functional theory; chromophore; nanocrystal; interface; photoexcitation; triplet state; surface electron transfer; electronic coupling strength; Kvantkemi; Quantum chemistry; Kvantkemi;

   Sammanfattning : Quantum chemical calculations have been used to model dye-sensitized nanostructured titanium dioxide systems that can be used in solar cells for solar energy to electricity conversion. Structural, electronic and spectral properties of isolated dyes and both bare and dye-sensitized TiO2 have been calculated with density functional theory, providing detailed information about both the separate parts and the dye-TiO2 interface. LÄS MER

7. 15. Quantum modeling of opticaland magnetic properties of the triplet state

   Författare :Oleksandr Loboda; KTH; []
   Nyckelord :;

   Sammanfattning : .... LÄS MER