Sökning: "exciton migration"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden exciton migration.

1. 1. Collective Excitation Dynamics in Molecular Aggregates

   Författare :Mats Dahlbom; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Fysik; Physics; computational methods; photosynthesis; femtosecond spectroscopy; Exciton; Polaron;

   Sammanfattning : The aim of this thesis is to study collective excitation dynamics in molecular aggregates. Half of the work presented here is method development and the remainder is application of these methods to several di.erent molecular aggregates. LÄS MER

3. 2. Ultrafast Photoinduced Processes in Core and Core–Shell Quantum Dots for Solar Cell Applications “Tiny Crystals for Big Applications”

   Författare :Mohamed Qenawy; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum dots; core–shell; electron injection; hole injection; hole trapping; exciton migration; solar cells; ultrafast dynamics; time-resolved spectroscopy.;

   Sammanfattning : The balance between our demands of energy and the energy we are consuming is not in equilibrium anymore. Therefore, the search for other energy resources is indispensable. Sustainable energy sources offer the alternative to the fossil fuels. LÄS MER

4. 3. Energy migration and charge formation in conjugated polymers

   Författare :Yuri Zaushitsyn; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; magnetic resonance; relaxation; spectroscopy; Kondenserade materiens egenskaper:elektronstruktur; egenskaper elektriska; magnetiska och optiska ; supraledare; magnetisk resonans; spektroskopi; supraconductors; magnetic and optical properties; electrical; energy transfer; Physics; Fysik; Condensed matter:electronic structure; transient absorption spectroscopy; conjugated polymer; charge photogeneration;

   Sammanfattning : The main part of the thesis is concerned with charge photogeneration in conjugated polymers. MeLPPP and POMeOPT films were investigated by transient absorption spectroscopy using different excitation photon energies and light intensities with and without an external electric field. LÄS MER

5. 4. Optical spectroscopy of InGaAs quantum dots

   Författare :Arvid Larsson; Per Olof Holtz; Artur Zrenner; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; quantum dot; semiconductor; optical properties; spin; transport; wetting layer; polarization; kvantprick; halvledare; optiska egenskaper; spin; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik; Materials science; Teknisk materialvetenskap; Condensed matter physics; Kondenserade materiens fysik; Semiconductor physics; Halvledarfysik;

   Sammanfattning : The work presented in this thesis deals with optical studies of semiconductor quantum dots (QDs) in the InGaAs material system. It is shown that for self-assembled InAs QDs, the interaction with the surrounding GaAs barrier and the InAs wetting layer (WL) in particular, has a very large impact on their optical properties. LÄS MER

7. 5. Structure-Property Relationships in Chromophore-Organogel Assemblies: Consequences for Triplet-Triplet Annihilation and Singlet Fission

   Författare :Deise Fernanda Barbosa de Mattos; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; photophysics; singlet fission; triplet-triplet annihilation upconversion; self-assembly; organogel.;

   Sammanfattning : Better utilization of the solar spectrum by absorbing photons that are currently wasted by solar cells, due to the bandgap mismatch with the semiconductor, will help to improve the device efficiency. Two low energy photons can be upconverted to one high energy photon through triplet-triplet annihilation (TTA-UC); one high energy photon can be down converted to form two charge carriers through singlet fission (SF). LÄS MER