School of Chemistry - Research Publications
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ItemEnhancement of efficiency in organic photovoltaic devices containing self-complementary hydrogen-bonding domains(BEILSTEIN-INSTITUT, 2013-06-06)Self-complementary hydrogen-bonding domains were incorporated as the electron deficient unit in "push-pull", p-type small molecules for organic photovoltaic active layers. Such compounds were found to enhance the fill factor, compared with similar non-self-organized compounds reported in the literature, leading to higher device efficiencies. Evidence is presented that the ability of these molecules to form one-dimensional hydrogen-bonded chains and subsequently exhibit hierarchical self-assembly into nanostructured domains can be correlated with improved device efficiency.
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ItemControlled synthesis of poly(3-hexylthiophene) in continuous flow(BEILSTEIN-INSTITUT, 2013-07-25)There is an increasing demand for organic semiconducting materials with the emergence of organic electronic devices. In particular, large-area devices such as organic thin-film photovoltaics will require significant quantities of materials for device optimization, lifetime testing and commercialization. Sourcing large quantities of materials required for the optimization of large area devices is costly and often impossible to achieve. Continuous-flow synthesis enables straight-forward scale-up of materials compared to conventional batch reactions. In this study, poly(3-hexylthiophene), P3HT, was synthesized in a bench-top continuous-flow reactor. Precise control of the molecular weight was demonstrated for the first time in flow for conjugated polymers by accurate addition of catalyst to the monomer solution. The P3HT samples synthesized in flow showed comparable performance to commercial P3HT samples in bulk heterojunction solar cell devices.
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ItemPhotophysics and aggregation effects of a triphenylamine-based dye sensitizer on metal-oxide nanoparticles suspended in an ion trap(ROYAL SOC CHEMISTRY, 2013)The photophysical behaviour of a triphenylamine-based organic dye sensitizer (Carbz-PAHTDTT) attached to alumina and titania nanoparticles (labelled Carbz-Al and Carbz-Ti, respectively) is examined in the absence and presence of the chenodeoxycholic acid (CDCA) coadsorber. The experiments are conducted in vacuo by suspending the target dye-sensitized nanoparticles within a quadrupole ion trap, where they are probed with laser radiation to obtain emission spectra and time-resolved excited state decay curves. For Carbz-Al, the dye's emission band is blue-shifted and the excited state lifetime is increased upon the coabsorption of CDCA, effects attributed to reduced dye aggregation. Compared to Carbz-Al, the Carbz-Ti excited state lifetimes are significantly shorter due to excited dye molecules injecting electrons into the titania conduction band. For Carbz-Ti, the electron injection quantum yields for the surfaces with CDCA (CDCA : dye = 25 : 1) and without CDCA are estimated to be 0.87 and 0.71, respectively. The gas-phase results demonstrate that Carbz-PAHTDTT dye aggregates are detrimental to the performance of a dye-sensitized solar cell.
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ItemBenzotriazole-based donor-acceptor conjugated polymers with a broad absorption in the visible range(ROYAL SOC CHEMISTRY, 2014-02-21)
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ItemThiazolyl substituted benzodithiophene copolymers: synthesis, properties and photovoltaic applications(Royal Society of Chemistry, 2014)Three new conjugated polymers based on 5-decylthiazol-2-yl substituted benzodithiophene have been synthesized by Stille cross-coupling polymerization. 1,3-Dibromo-5-octylthieno[3,4-c]pyrrole-4,6-dione (M1), 2,5-diethylhexyl-3,6-bis(5-bromothiophen-2-yl)pyrrolo[3,4-c]-pyrrole-1,4-dione (M2) and 4,6-dibromo-thieno[3,4-b]thiophene-2-dodecyl carboxylate (M3) were used as acceptor building blocks for the synthesis of conjugated donor-acceptor polymers. The thermal, optical, electrochemical, and photovoltaic properties of the synthesized polymers were studied.
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ItemSingle Isomer of Indene-C70 Bisadduct-Isolation and Performance in Bulk Heterojunction Solar Cells(AMER CHEMICAL SOC, 2014-02-25)
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ItemOrganic Solar Cells Using a High-Molecular-Weight Benzodithiophene-Benzothiadiazole Copolymer with an Efficiency of 9.4%(WILEY-V C H VERLAG GMBH, 2015-01-27)A high molecular weight donor-acceptor conjugated polymer is synthesized using the Suzuki polycondensation method. Using this polymer, a single-junction bulk-heterojunction solar cell is fabricated giving a power conversion efficiency of 9.4% using a fullerene-modified ZnO interlayer at the cathode contact.
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ItemOrganic Photovoltaic MaterialsDesign, Synthesis and Scale-Up(WILEY-V C H VERLAG GMBH, 2015-12)This account describes the work of our group in the area of organic photovoltaics in the past six years. The emphasis is on our experiences in the development of the organic materials, their characterization, scale-up and application in devices. We share our insight into the relationship between synthetic methods, molecular properties, bulk material properties and device performance.
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ItemDevelopment of a High-Performance Donor Acceptor Conjugated Polymer: Synergy in Materials and Device Optimization(AMER CHEMICAL SOC, 2016-05-24)