Organic photovoltaics: An investigation of interface layers and space-charge effects

Simple item page
dc.contributor.advisorCurran, Seamus A.
dc.contributor.committeeMemberWood, Lowell T.
dc.contributor.committeeMemberStokes, Donna W.
dc.contributor.committeeMemberBensaoula, Abdelhak
dc.contributor.committeeMemberClarke, Mark S. F.
dc.creatorZhang, Xin 1987-
dc.date.accessioned2015-01-04T06:02:01Z
dc.date.available2015-01-04T06:02:01Z
dc.date.createdDecember 2013
dc.date.issued2013-12
dc.date.updated2015-01-04T06:02:02Z
dc.description.abstractThe research described in this thesis includes interface study of organic photovoltaics, and the study of the space-charge effect on organic electronics from a photonics perspective. First, dynamic spin coating was used as a deposition technique in the fabrication of p-n bilayer organic photovoltaics, solvents used in the fabrication were carefully selected to generate different p-n interface morphologies from low level inter-digitated to flat, and it was found that the interface morphology can significantly affect the device performance. Stability optimization was carried out by using electro-polymerized PEDOT:PSS (EPEDOT:PSS) as a replacement for the spin coated PEDOT:PSS (SPEDOT:PSS) as hole transport layer (HTL). The X-ray photoelectron spectroscopy study shows a decrease of PSS to PEDOT ratio as well as a lower Indium atomic concentration in the electro-polymerized film. The device fabricated with EPEDOT:PSS showed an appreciable improvement in the stability property. The highly conductive PEDOT:PSS was designed to replace the Indium Tin Oxide (ITO)/PEDOT:PSS junction as the new anode to make the device fully flexible. The ITO-free device showed higher power conversion efficiency than the ITO-based device. However, the light-intensity study suggests that due to the less anode conductivity in the ITO-free device, more space-charge effects can be observed and in turn causes a higher bimolecular recombination rate in the flexible device. Using the flexible substrates with alternative anodes, examining their current voltage performance under different light intensity, the correlation of open circuit voltage (VOC) with anode transport property was studied. A simple model on VOC as a function of space charge density and photo-generated charge density was applied and successfully explained how space-charge affects the changing trend of VOC.
dc.description.departmentPhysics, Department of
dc.format.digitalOriginborn digital
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/10657/862
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectOrganic photovoltaics
dc.subjectInterfaces
dc.subjectElectro-polymerization
dc.subjectModified PEDOT:PSS
dc.subjectDegradation
dc.subjectLight-intensity study
dc.subjectSpace charge
dc.subject.lcshPhysics
dc.titleOrganic photovoltaics: An investigation of interface layers and space-charge effects
dc.type.dcmiText
dc.type.genreThesis
thesis.degree.collegeCollege of Natural Sciences and Mathematics
thesis.degree.departmentPhysics, Department of
thesis.degree.disciplinePhysics
thesis.degree.grantorUniversity of Houston
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

Files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
Name:
ZHANG-DISSERTATION-2013.pdf
Size:
5.48 MB
Format:
Adobe Portable Document Format
Download

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
Name:
LICENSE.txt
Size:
1.84 KB
Format:
Plain Text
Description:
Download

Collections

Published ETD Collection