title: Processing and N-Doping of Polymer and Carbon Nanotube Field-Effect-Transistors
creator: Schneider, Severin
subject: ddc-500
subject: 500 Natural sciences and mathematics
subject: ddc-540
subject: 540 Chemistry and allied sciences
description: Semiconducting, single-walled carbon nanotubes (SWCNTs) have mechanical and electronic  properties that render them a promising material for solution-processable, stretchable  and flexible electronics. However, their strong tendency to form aggregates in dispersion  constitutes a large obstacle to realize the film uniformity necessary for the transition  of devices from laboratory to commercial scale. The resulting inhomogeneities in film  morphology lead to an undesired spread in device performance.  Based on the tailored formulation of colloidal inks via suitable solvents and additives the  first part of this thesis presents a simple yet effective method to slow down aggregation  of polymer-wrapped SWCNTs in organic solvents. This effect on aggregation by 1,10-  phenanthroline as a stabilizing additive can be monitored with time-dependent absorption  spectroscopy. The improved homogeneity of the SWCNT networks deposited from stabilized  dispersions after several days of ink storage lead to higher charge carrier mobilities with  strongly reduced device-to-device variations compared to inks without additive.  The intrinsic ambipolarity of SWCNTs is a great disadvantage for their use in electronic  circuits as it leads to large power dissipation. While pure hole conduction can be achieved  relatively easily by doping with, for example, ambient oxygen, facilitating exclusive electron  conduction represents a large challenge. A solution-processable n-dopant from the family of  guanidino-functionalized aromatics (GFAs) is introduced to overcome this limitation. The  resulting SWCNT network field-effect transistors (FETs) exhibit pure electron transport  with high mobility while hole transport is fully suppressed, excellent switching behavior  and good operational stability. Their application potential (combined with a doped p-type  FET) is highlighted by complementary inverters with very low power dissipation.  This modification of the charge transport behavior is applied to another promising solution-processable semiconductor, i.e., donor-acceptor-polymers. Doping of these polymers with  two GFA compounds under various processing conditions improves electron injection  and transport while hole transport is suppressed. Again, these transistors display good  environmental stability under operating conditions. The extended applicability of the  newly introduced GFA dopants to different semiconductors emphasizes their potential for  transistors based on solution-processable semiconductor
date: 2021
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/30703/1/Dissertation_Severin_Schneider_Ver%C3%B6ffentl.pdf
identifier: DOI:10.11588/heidok.00030703
identifier: urn:nbn:de:bsz:16-heidok-307033
identifier:   Schneider, Severin  (2021) Processing and N-Doping of Polymer and Carbon Nanotube Field-Effect-Transistors.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/30703/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng