Energy transfer mechanisms in CdSe/CdS nanorod heterostructures.
A series of time-resolved transient absorption spectroscopy experiments were performed on ensembles of CdSe/CdS dot/rod nano-hetero-structures dispersed in toluene. The resulting decay dynamics were quantified via data fitting of the differential transmission of probe laser pulses to multi-exponenti...
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sg-ntu-dr.10356-428062023-02-28T23:16:32Z Energy transfer mechanisms in CdSe/CdS nanorod heterostructures. Ngiam, Song Wee. Sum Tze Chien School of Physical and Mathematical Sciences Xing Gui Chuan DRNTU::Science::Physics A series of time-resolved transient absorption spectroscopy experiments were performed on ensembles of CdSe/CdS dot/rod nano-hetero-structures dispersed in toluene. The resulting decay dynamics were quantified via data fitting of the differential transmission of probe laser pulses to multi-exponential decay functions. The lifetimes extracted from the data fit indicates the timescales over which the recombination processes within the system of study occur. A plausible model was proposed in order to account for the various trends in lifetimes with increasing laser pump fluences. The model also identified the specific state transitions for which current literature enfolds as ”Auger processes”, and alludes the observed suppression of such non-radiative recombinations with increasing rod lengths, to that of a decrease in the effective overlap, in the wavefunction of a donor electron in the sulphur vacancy states, with that of the empty states above the conduction band-edge. A proof-of-concept which showed that the suppressed Auger processes can lead to lasing in such ensembles of nanocrystallites upon alignment and concentration, was also demonstrated through the realization of amplified spontaneous emission. Bachelor of Science in Physics 2011-01-11T07:14:16Z 2011-01-11T07:14:16Z 2010 2010 Final Year Project (FYP) http://hdl.handle.net/10356/42806 en 130 p. application/pdf |
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DRNTU::Science::Physics Ngiam, Song Wee. Energy transfer mechanisms in CdSe/CdS nanorod heterostructures. |
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A series of time-resolved transient absorption spectroscopy experiments were performed on ensembles of CdSe/CdS dot/rod nano-hetero-structures dispersed in toluene. The resulting decay dynamics were quantified via data fitting of the differential transmission of probe laser pulses to multi-exponential decay functions. The lifetimes extracted from the data fit indicates the timescales over which the recombination processes within the system of study occur.
A plausible model was proposed in order to account for the various trends in lifetimes with increasing laser pump fluences. The model also identified the specific state transitions for which current literature enfolds as ”Auger processes”, and alludes the observed suppression of such non-radiative recombinations with increasing rod lengths, to that of a decrease in the effective overlap, in the wavefunction of a donor electron in the sulphur vacancy states, with that of the empty states above the conduction band-edge.
A proof-of-concept which showed that the suppressed Auger processes can lead to lasing in such ensembles of nanocrystallites upon alignment and concentration, was also demonstrated through the realization of amplified spontaneous emission. |
author2 |
Sum Tze Chien |
author_facet |
Sum Tze Chien Ngiam, Song Wee. |
format |
Final Year Project |
author |
Ngiam, Song Wee. |
author_sort |
Ngiam, Song Wee. |
title |
Energy transfer mechanisms in CdSe/CdS nanorod heterostructures. |
title_short |
Energy transfer mechanisms in CdSe/CdS nanorod heterostructures. |
title_full |
Energy transfer mechanisms in CdSe/CdS nanorod heterostructures. |
title_fullStr |
Energy transfer mechanisms in CdSe/CdS nanorod heterostructures. |
title_full_unstemmed |
Energy transfer mechanisms in CdSe/CdS nanorod heterostructures. |
title_sort |
energy transfer mechanisms in cdse/cds nanorod heterostructures. |
publishDate |
2011 |
url |
http://hdl.handle.net/10356/42806 |
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1759856529306025984 |