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Chen, Xialing (2015) OPTICAL AND ELECTRICAL PROPERTIES OF ORGANIC SEMICONDUCTORS: EXPERIMENT AND SIMULATION. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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This dissertation focuses on the charge transport of organic semiconductors, particularly in the presence of traps and defects. Rather than attempting to ultimately pure materials, intentional mixtures were made and studied. The materials were characterized by electrochemistry, UV/Vis spectroscopy and computational studies using density functional theory (DFT) and time dependent DFT (TDDFT).
In experiment, the phthalocyanine films were prepared from solution. We explored how to improve the coatings of organic semiconductors on different substrates. Moreover, the effect of how intentionally introduced traps or barriers change the charge transport was studied using the spin-coated octabutoxy phthalocyanine and naphthalocyanine mixed films. It was found that the introduced barriers decreased the mobility. And a negative differential resistance was observed in the saturated region of the Field-effect-transistor (FET) measurements in the mixed films.
In simulation, density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were performed to predict optical and electrical parameters of the semiconducting materials. In the calculations of phthalocyanine molecules with different metal or ligand substitutions, it was found that the electrical and optical properties of the phthalocyanine semiconductors could be tuned more with different organic ligands than by modifying the metal centers. For the mixed valence (MV) bipyridine bridged triarylamine systems, the simulation perfectly predicted the absorption of the spectra and the blue-shift of the spectra with different solvents reported by our collaborator in experiments.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Chen, Xialingxic18@pitt.eduXIC18
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairHutchison, Geoffrey R geoffh@pitt.eduGEOFFH
Committee MemberWaldeck, Daviddave@pitt.eduDAVE
Committee MemberStar, Alexanderastar@pitt.eduASTAR
Committee MemberYun , Minheemiy16@pitt.eduMIY16
Date: 18 June 2015
Date Type: Publication
Defense Date: 7 January 2014
Approval Date: 18 June 2015
Submission Date: 13 February 2015
Access Restriction: 1 year -- Restrict access to University of Pittsburgh for a period of 1 year.
Number of Pages: 163
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: organic semiconductor optical electrical
Date Deposited: 18 Jun 2015 14:43
Last Modified: 15 Nov 2016 14:26


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