Electrochemical crosslinking strategies using redox-active units for optoelectronic thin film applications

In this dissertation the electrochemical reactivity of different classes of redox molecules of optoelectronics interest, including thiophene and arylamine derivatives, is studied and exploited to crosslink precursor systems endowed with multiple dimerization sites to obtain functional electroactive films. The latter are characterized by a well-defined and controlled π-conjugation and redox behavior, which can be directly related to the one of the dimer of the starting redox unit. In the first section of the thesis, the electrochemical crosslinking from solution of different multimeric systems, including arylamine based push-pull molecules was exploited. In the second part of the thesis, insight of oxidative crosslinking as a post-solution deposition step to obtain electroactive films is provided. The dimerizing ability of triarylamine (TPA) and carbazole (Cbz) in the form of redox-active pendant units on a saturated polymer backbone as crosslinkers was studied upon oxidation

Bodily practices as vehicles for dehumanization in an institution for mental defectives

Open accessThis article analyzes the processes of dehumanization that occurred in the Michener Center, a total institution for the purported care and training of people deemed to be mental defectives1 that operated in Alberta, Canada. I report on qualitative interviews with 22 survivors, three ex-workers, and the institutional archival record, drawing out the ways that dehumanization was accomplished through bodily means and the construction of embodied otherness along several axes. First, inmates’ bodies were erased or debased as unruly matter out of place that disturbed the order of rational modernity, a move that meant inmates were not seen as deserving or even requiring of normal human consideration. Spatial practices within the institution included panopticism and isolation, constructing inmates as not only docile but as unworthy of contact and interaction. Dehumanization was also seen as necessary to and facilitative of patient care; to produce inmates as subhuman permitted efficiency, but also neglect and abuse. Finally, practices of hygiene and sequestering the polluting bodies of those deemed mentally defective sustained and justified dehumanization. These practices had profound effects for inmates and also for those charged with caring for them.Ye

Embodied action, embodied theory: understanding the body in society

Open access[No abstract available]Ye

Living archives on eugenics in Western Canada : interview training handbook : interviewing protocols : conducted at the University of Calgary, May 5-7, 2011

This training kit has evolved through several meetings, discussions, and workshops. It is compiled based upon several key documents including the CURA Living Archive on Eugenics (LAE) main protocol, interim workshop materials, and ethics proposals that have been submitted to the various partner universities. It has also been adapted from the Montreal Life Stories Training Workshop from the Centre for Oral History and Digital Storytelling, Concordia University, September 2010. This training aims to get interviewers thinking about how to conduct qualitative interviews, but more importantly, it seeks to engage interviewers with processes of how to be sensitive and aware of interviewees’ emotional and psychological needs during the research process. It will address questions of recruiting participants, legal and ethical considerations building up to the interview itself, conducting interviews with interviewees and community advocates, building trust and establishing rapport, working with interview technology, and more subtle questions of ethics, sensitivity and asking questions of people who have not only have been traumatized, but who may have intellectual disabilities or mental health challenges.Community-University Research Alliance (Victoria, B.C.)Social Sciences and Humanities Research Council of Canad

In Situ Electrochemical Investigations of Inherently Chiral 2,2′-Biindole Architectures with Oligothiophene Terminals

AbstractThe synthesis and characterization of three new inherently chiral N,N′‐dipropyl‐3,3′‐diheteroaryl‐2,2′‐biindole monomers, nicknamed Ind2T4, Ind2T6 and Ind2Ph2T4, which differ in the number of thiophenes as terminals, are reported. In addition to a full monomer characterization, stable electroactive oligomeric films were obtained by electro‐oxidation upon cycling to potentials which activate the thiophene terminals. Cyclic voltammetry, UV‐Vis‐NIR spectroelectrochemistry and in situ conductance measurements show that oligomeric films of Ind2T6 present the best stability and electrochromic switching performance. Enantioselective tests with a chiral ferrocene amine clearly show the potential as chiral selectors for analytical and sensing purposes

Chemical Doping of Conjugated Polymers with the Strong Oxidant Magic Blue

Molecular doping of organic semiconductors is a powerful tool for the optimization of organic electronic devices and organic thermoelectric materials. However, there are few redox dopants that have a sufficiently high electron affinity to allow the doping of conjugated polymers with an ionization energy of more than 5.3\ua0eV. Here, p-doping of a broad palette of conjugated polymers with high ionization energies is achieved by using the strong oxidant tris(4-bromophenyl)ammoniumyl hexachloroantimonate (Magic Blue). In particular diketopyrrolopyrrole (DPP)-based copolymers reach a conductivity of up to 100 S cm−1 and a thermoelectric power factor of 10 \ub5W m−1 K−2. Further, both electron paramagnetic resonance (EPR) as well as a combination of spectroelectrochemistry and chronoamperometry is used to estimate the charge-carrier density of the polymer PDPP-3T doped with Magic Blue. A molar attenuation coefficient of 6.0\ua0\ub1\ua00.2 7 103 m2 mol−1 is obtained for the first polaronic sub-bandgap absorption of electrochemically oxidized PDPP-3T. Comparison with chemically doped PDPP-3T suggests a charge-carrier density on the order of 1026 m−3, which yields a charge-carrier mobility of up to 0.5 cm2 V−1 s−1 for the most heavily doped material

In situ electrochemical investigations of inherently chiral 2,2′‐biindole architectures with oligothiophene terminals

The synthesis and characterization of three new inherently chiral N,N′‐dipropyl‐3,3′‐diheteroaryl‐2,2′‐biindole monomers, nicknamed Ind2T4, Ind2T6 and Ind2Ph2T4, which differ in the number of thiophenes as terminals, are reported. In addition to a full monomer characterization, stable electroactive oligomeric films were obtained by electro‐oxidation upon cycling to potentials which activate the thiophene terminals. Cyclic voltammetry, UV‐Vis‐NIR spectroelectrochemistry and in situ conductance measurements show that oligomeric films of Ind2T6 present the best stability and electrochromic switching performance. Enantioselective tests with a chiral ferrocene amine clearly show the potential as chiral selectors for analytical and sensing purposes.Integrated Quantum Science and TechnologyCarl-Zeiss-FoundationMinistero dell’Istruzione, Università e RicercaProjekt DEA

Conductance and spectroscopic mapping of EDOT polymer films upon electrochemical doping

Abstract This paper deals with the electrochemical doping of different poly(ethylenedioxythiophene) (PEDOT)-based active layers performed in an organic electrochemical transistor configuration through the mapping of in situ conductance trends during electrochemical doping and dedoping. The experiments are complemented by UV/Vis/NIR in situ spectroelectrochemistry in the wavelength range from 400 to 1600 nm, which allow monitoring of the development of the neutral and charged redox species. Both electropolymerized EDOT-based layers and solution-processed chemically synthesized PEDOT films are characterized. In addition to pure electropolymerized PEDOT (e-PEDOT), tris(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)phenyl) (TPA-EDOT3) is electrodeposited to generate highly branched networks of P(TPA-EDOT3). The solution-deposited PEDOT films contain poly(ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with ratios of 1:2.5 and 1:6. Overall, we find that e-PEDOT and PEDOT:PSS(1:2.5) behave like classical conjugated polymers with a plateau-like conductance over a wide potential region. In contrast, PEDOT:PSS(1:6) and P(TPA-EDOT3) show rather bell-shaped conductance profiles. The mixed-valence conductivity model is used to interpret the experimental results in terms of the number of accessible redox states. We suggest that the bell-shaped conductance in the case of PEDOT:PSS(1:6) is caused by a high amount of PSS insulator that limits the inter-chain interaction between PEDOT moieties and in the case of P(TPA-EDOT3) by its distorted molecular architecture

Theoretical insights into the Electronic and Structural Properties of New, Low-band Gap Inherently Chiral Ethylendioxythiophene-based Oligothiophene

In the last years, conjugated oligothiophene macrocycles have attracted increasing scientific interest due to some peculiar properties related to their cyclic structure [1-3]. T. Benincori et al. synthesized the 2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bithianaphthene nicknamed BT2T4 (Figure 1) that represents the first member of a new class of chiral oligothiophenes in which chirality results from a tailored torsion produced in the polyconjugated backbone and not from the presence of stereogenic centres, external to it. Interestingly, the FeCl3 oxidation of the enantiopure BT2T4 produce a mixture of chiral macrocycles, like dimers and trimers. [4] Recently, also thanks to DFT and TD-DFT calculations, we have studied the new monomer BT2E4 in order to investigate the role of the insertion of 3,4-ethylenedioxythiophene (EDOT) units on the electronic and molecular properties of neutral and charged monomer and oligomer species. Furthermore, the electroactive films were evaluated by cyclic voltammetry (CV), UV/vis spectroelectrochemistry and CV coupled with in-situ conductance measurements. [5]Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec