Title:
Patternable electrophosphorescent organic light-emitting diodes with solution-processed organic layers

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dc.contributor.advisor Kippelen, Bernard
dc.contributor.author Haldi, Andreas en_US
dc.contributor.committeeMember Brand Oliver
dc.contributor.committeeMember Bredas Jean-Luc
dc.contributor.committeeMember Dupuis Russell D.
dc.contributor.committeeMember Smith Glenn S.
dc.contributor.department Electrical and Computer Engineering en_US
dc.date.accessioned 2009-01-22T15:43:40Z
dc.date.available 2009-01-22T15:43:40Z
dc.date.issued 2008-08-08 en_US
dc.description.abstract Organic light-emitting diodes (OLEDs) have drawn much attention in the last two decades. In recent years, the power efficiency of OLEDs has been increased to exceed the efficiency of fluorescent light bulbs. However, such high-efficiency devices are typically based on small molecules that have to be evaporated in vacuum. A much higher fabrication throughput and therefore lowered costs are expected if high-efficiency OLEDs were processed from solution. This thesis shows how solution-processed electrophosphorescent multilayer OLEDs can be achieved by starting with an evaporated three-layer device structure and replacing layer by layer with a solution-processed layer. First, the hole-transport layer was replaced by a polymer and high efficiencies were observed when using a hole-transport polymer with a high ionization potential and a low hole mobility. Then, the emissive layer was replaced by a copolymer consisting of hole-transport groups and emissive complexes in its side-chains. OLEDs with four different colors are shown where the orange devices showed the highest efficiency. The orange copolymer was further optimized by making changes to the chemical nature of the polymer, such as different molecular weight, different concentrations of the emissive complex and different linkers between the side-chains and the polymer backbone. Finally, a three-layer solution-processed OLED was fabricated by crosslinking the hole-transport and the emissive layer, and by spin-coating an electron-transport polymer on top. Moreover, using the photocrosslinking properties of the emissive layer, solution-processed multilayer OLEDs of two different colors were patterned using photolithography to fabricate a white-light source with a tunable emission spectrum. Furthermore, with more and more organic semiconductors being integrated into the circuitry of commercial products, good electrical models are needed for a circuit design with predictive capabilities. Therefore, a model for the example of an organic single-layer diode is introduced in the last chapter of this thesis. The model has been implemented into SPICE and consists of an equivalent circuit that is mostly based on intrinsic material properties, which can be measured in independent experiments. The model has been tested on four different organic materials, and good agreement between model and experimental results is shown. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/26533
dc.publisher Georgia Institute of Technology en_US
dc.subject Equivalent circuit en_US
dc.subject Copolymer en_US
dc.subject Phosphorescence en_US
dc.subject Solution-processing en_US
dc.subject OLED en_US
dc.subject Organic light-emitting diodes en_US
dc.subject.lcsh Light emitting diodes
dc.subject.lcsh Electroluminescence
dc.subject.lcsh Organic thin films
dc.subject.lcsh Crosslinked polymers
dc.subject.lcsh Polymers
dc.title Patternable electrophosphorescent organic light-emitting diodes with solution-processed organic layers en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Kippelen, Bernard
local.contributor.corporatename School of Electrical and Computer Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 89dff3fa-f69f-48dc-a1b2-89e73be81537
relation.isOrgUnitOfPublication 5b7adef2-447c-4270-b9fc-846bd76f80f2
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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