Charge Carrier Dynamics at Silver Nanocluster-Molecular Acceptor Interfaces

Handle URI:
http://hdl.handle.net/10754/625307
Title:
Charge Carrier Dynamics at Silver Nanocluster-Molecular Acceptor Interfaces
Authors:
Almansaf, Abdulkhaleq ( 0000-0001-7021-6534 )
Abstract:
A fundamental understanding of interfacial charge transfer at donor-acceptor interfaces is very crucial as it is considered among the most important dynamical processes for optimizing performance in many light harvesting systems, including photovoltaics and photo-catalysis. In general, the photo-generated singlet excitons in photoactive materials exhibit very short lifetimes because of their dipole-allowed spin radiative decay and short diffusion lengths. In contrast, the radiative decay of triplet excitons is dipole forbidden; therefore, their lifetimes are considerably longer. The discussion in this thesis primarily focuses on the relevant parameters that are involved in charge separation (CS), charge transfer (CT), intersystem crossing (ISC) rate, triplet state lifetime, and carrier recombination (CR) at silver nanocluster (NCs) molecular-acceptors interfaces. A combination of steady-state and femto- and nanosecond broadband transient absorption spectroscopies were used to investigate the charge carrier dynamics in various donor-acceptor systems. Additionally, this thesis was prolonged to investigate some important factors that influence the charge carrier dynamics in Ag29 silver NCs donor-acceptor systems, such as the metal doping and chemical structure of the nanocluster and molecular acceptors. Interestingly, clear correlations between the steady-state measurements and timeresolved spectroscopy results are found. In the first study, we have investigated the interfacial charge transfer dynamics in positively charged meso units of 5, 10, 15, 20-tetra (1- methyl-4-pyridino)-porphyrin tetra (p-toluene sulfonate) (TMPyP) and neutral charged 5, 10, 15, 20-tetra (4-pyridyl)-porphyrin (TPyP), with negatively charged undoped and gold (Au)- doped silver Ag29 NCs. Moreover, this study showed the impact of Au doping on the charge carrier dynamics of the system. In the second study, we have investigated the interfacial charge transfer dynamics in [Pt2 Ag23 Cl7 (PPh3)10] silver NCs doped with platinum (Pt), with neutral charged 5, 10, 15, 20-tetra (4-pyridyl)-porphyrin (TPyP). Here, we evaluated the effects of Pt (II) doping on the interfacial charge-transfer dynamics between TPyP and silver NCs.
Advisors:
Mohammad, Omar F. ( 0000-0001-8500-1130 )
Committee Member:
Bakr, Osman M. ( 0000-0002-3428-1002 ) ; Takanabe, Kazuhiro ( 0000-0001-5374-9451 )
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Program:
Chemical Sciences
Issue Date:
Jul-2017
Type:
Thesis
Appears in Collections:
Theses

Full metadata record

DC FieldValue Language
dc.contributor.advisorMohammad, Omar F.en
dc.contributor.authorAlmansaf, Abdulkhaleqen
dc.date.accessioned2017-08-08T05:47:05Z-
dc.date.available2017-08-08T05:47:05Z-
dc.date.issued2017-07-
dc.identifier.urihttp://hdl.handle.net/10754/625307-
dc.description.abstractA fundamental understanding of interfacial charge transfer at donor-acceptor interfaces is very crucial as it is considered among the most important dynamical processes for optimizing performance in many light harvesting systems, including photovoltaics and photo-catalysis. In general, the photo-generated singlet excitons in photoactive materials exhibit very short lifetimes because of their dipole-allowed spin radiative decay and short diffusion lengths. In contrast, the radiative decay of triplet excitons is dipole forbidden; therefore, their lifetimes are considerably longer. The discussion in this thesis primarily focuses on the relevant parameters that are involved in charge separation (CS), charge transfer (CT), intersystem crossing (ISC) rate, triplet state lifetime, and carrier recombination (CR) at silver nanocluster (NCs) molecular-acceptors interfaces. A combination of steady-state and femto- and nanosecond broadband transient absorption spectroscopies were used to investigate the charge carrier dynamics in various donor-acceptor systems. Additionally, this thesis was prolonged to investigate some important factors that influence the charge carrier dynamics in Ag29 silver NCs donor-acceptor systems, such as the metal doping and chemical structure of the nanocluster and molecular acceptors. Interestingly, clear correlations between the steady-state measurements and timeresolved spectroscopy results are found. In the first study, we have investigated the interfacial charge transfer dynamics in positively charged meso units of 5, 10, 15, 20-tetra (1- methyl-4-pyridino)-porphyrin tetra (p-toluene sulfonate) (TMPyP) and neutral charged 5, 10, 15, 20-tetra (4-pyridyl)-porphyrin (TPyP), with negatively charged undoped and gold (Au)- doped silver Ag29 NCs. Moreover, this study showed the impact of Au doping on the charge carrier dynamics of the system. In the second study, we have investigated the interfacial charge transfer dynamics in [Pt2 Ag23 Cl7 (PPh3)10] silver NCs doped with platinum (Pt), with neutral charged 5, 10, 15, 20-tetra (4-pyridyl)-porphyrin (TPyP). Here, we evaluated the effects of Pt (II) doping on the interfacial charge-transfer dynamics between TPyP and silver NCs.en
dc.language.isoenen
dc.subjectMetal Nanoclusteren
dc.subjectDonor-Acceptoren
dc.subjectInterfacesen
dc.subjectCharge Transferen
dc.subjectChange Seperationen
dc.titleCharge Carrier Dynamics at Silver Nanocluster-Molecular Acceptor Interfacesen
dc.typeThesisen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen
dc.contributor.committeememberBakr, Osman M.en
dc.contributor.committeememberTakanabe, Kazuhiroen
thesis.degree.disciplineChemical Sciencesen
thesis.degree.nameMaster of Scienceen
dc.person.id143746en
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