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W Bras - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, thermal processing, and Thin Film Morphology of poly(3-hexylthiophene)-poly(styrenesulfonate) block copolymers
Macromolecules, 2015Co-Authors: Harikrishna Erothu, Joanna Kolomanska, Dargie Deribew, Christine Dagron-lartigau, Priscilla Johnston, Alberto Gregori, Daniel T. W. Toolan, Giuseppe Portale, Stefan Schumann, W BrasAbstract:A series of novel block copolymers, processable from single organic solvents and subsequently rendered amphiphilic by thermolysis, have been synthesized using Grignard metathesis (GRIM) and reversible addition–fragmentation chain transfer (RAFT) polymerizations and azide–alkyne click chemistry. This chemistry is simple and allows the fabrication of well-defined block copolymers with controllable block lengths. The block copolymers, designed for use as interfacial adhesive layers in organic photovoltaics to enhance contact between the photoactive and hole transport layers, comprise printable poly(3-hexylthiophene)-block-poly(neopentyl p-styrenesulfonate), P3HT-b-PNSS. Subsequently, they are converted to P3HT-b-poly(p-styrenesulfonate), P3HT-b-PSS, following deposition and thermal treatment at 150 °C. Grazing incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS) revealed that Thin Films of the amphiphilic block copolymers comprise lamellar nanodomains of P3HT crystallites that can be pushed further apart by increasing the PSS block lengths. The approach of using a thermally modifiable block allows deposition of this copolymer from a single organic solvent and subsequent conversion to an amphiphilic layer by nonchemical means, particularly attractive to large scale roll-to-roll industrial printing processes.
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Synthesis, thermal processing, and Thin Film Morphology of poly(3-hexylthiophene)-poly(styrenesulfonate) block copolymers
Macromolecules, 2015Co-Authors: Harikrishna Erothu, Joanna Kolomanska, Dargie Deribew, Priscilla Johnston, Alberto Gregori, Daniel T. W. Toolan, Giuseppe Portale, Stefan Schumann, Christine Lartigau-dagron, W BrasAbstract:A series of novel block copolymers, processable from single organic solvents and subsequently rendered amphiphilic by thermolysis, have been synthesized using Grignard metathesis (GRIM) and reversible addition-fragmentation chain transfer (RAFT) polymerizations and azide-alkyne click chemistry. This chemistry is simple and allows the fabrication of well-defined block copolymers with controllable block lengths. The block copolymers, designed for use as interfacial adhesive layers in organic photovoltaics to enhance contact between the photoactive and hole transport layers, comprise printable poly(3-hexylthiophene)-block-poly(neopentyl p-styrenesulfonate), P3HT-b-PNSS. Subsequently, they are converted to P3HT-b-poly(p-styrenesulfonate), P3HT-b-PSS, following deposition and thermal treatment at 150 °C. Grazing incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS) revealed that Thin Films of the amphiphilic block copolymers comprise lamellar nanodomains of P3HT crystallites that can be pushed further apart by increasing the PSS block lengths. The approach of using a thermally modifiable block allows deposition of this copolymer from a single organic solvent and subsequent conversion to an amphiphilic layer by nonchemical means, particularly attractive to large scale roll-to-roll industrial printing processes. © 2015 American Chemical Society.
Ji-seon Kim - One of the best experts on this subject based on the ideXlab platform.
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In situ formation of organic–inorganic hybrid nanostructures for photovoltaic applications
Faraday discussions, 2014Co-Authors: Sebastian Wood, C. Tsoi, Oliver Garnett, Nurlan Tokmoldin, Saif A. Haque, Ji-seon KimAbstract:The performance of hybrid (organic–inorganic) photovoltaic devices is critically dependent on the Thin Film Morphology. This work studies the Film formation process using the in situ thermal decomposition of a soluble precursor to form a well-distributed network of CdS nanoparticles wiThin a poly(3-hexylthiophene) (P3HT) polymer matrix. Resonant Raman spectroscopy is used to probe the formation of the inorganic nanoparticles and the corresponding changes in the molecular order of the polymer. We find that the CdS precursor decomposes rapidly upon heating to 160 °C, but that this has a disruptive effect on the P3HT. The extent of this disruption can be controlled by adjusting the annealing temperature, and nanowire aggregates of P3HT are found to have increased susceptibility. Atomic force microscopy reveals that at high temperatures (>200 °C), cracks form in the Film, resulting in a ‘plateau’-like microstructure. In order to retain the preferable ‘granular’ microstructure and to control the molecular disruption, low decomposition temperatures are needed. This work identifies a particular problem for optimising the hybrid Thin Film Morphology and shows how it can be partially overcome.
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In-situ monitoring of molecular vibrations of two organic semiconductors in photovoltaic blends and their impact on Thin Film Morphology
Applied Physics Letters, 2013Co-Authors: C. Tsoi, Weimin Zhang, Joseph Razzell Hollis, Minwon Suh, Martin Heeney, Iain Mcculloch, Ji-seon KimAbstract:We report in-situ simultaneous monitoring of molecular vibrations of two components in organic photovoltaic blends using resonant Raman spectroscopy. Blend Films were composed of a low bandgap copolymer thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTTT) and (6,6)-phenyl-C71-butyric acid ester (PC70BM). Changes in Raman spectra associated with crystallization processes of each component and their impact on Thin Film Morphology were studied during thermal annealing and cooling processes. Transition temperatures to crystalline phases in blends were measured at ∼150 °C and ∼170 °C for DPPTTT and PC70BM, respectively. Such phase changes lead to modifications in local chemical composition reducing relative Raman peak intensities (IPC70BM/IDPPTTT) from ∼0.4 in PC70BM-rich domains to ∼0.15 in homogeneous areas.
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Probing Thin-Film Morphology of conjugated polymers by Raman spectroscopy
Journal of Applied Physics, 2010Co-Authors: Jessica M. Winfield, Carrie L. Donley, Richard H. Friend, Ji-seon KimAbstract:We use Raman spectroscopy to investigate the Thin-Film Morphology of conjugated polymers [poly(9,9-di-n-octylfluorene-alt-benzothiadiazole (F8BT)] in terms of the polymer chain conformation at interfaces with quartz, a crosslinked benzocyclobutene derivative, polyvinylphenol, and poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate). The polymer chains near the substrate interface adopt a more planar conformation (lower torsion angle between fluorene and benzothiadiazole units) than chains in the bulk of the Film for all substrates studied. On annealing, polymer chains both near the interface and in the bulk of the Film adopt more planar conformations than in their pristine states but to a different degree. The influence of F8BT molecular weight on polymer chain conformation near the substrate interface is also examined. These results are confirmed by additional absorption and photoluminescence measurements.
Iain Mcculloch - One of the best experts on this subject based on the ideXlab platform.
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In-situ monitoring of molecular vibrations of two organic semiconductors in photovoltaic blends and their impact on Thin Film Morphology
Applied Physics Letters, 2013Co-Authors: C. Tsoi, Weimin Zhang, Joseph Razzell Hollis, Minwon Suh, Martin Heeney, Iain Mcculloch, Ji-seon KimAbstract:We report in-situ simultaneous monitoring of molecular vibrations of two components in organic photovoltaic blends using resonant Raman spectroscopy. Blend Films were composed of a low bandgap copolymer thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTTT) and (6,6)-phenyl-C71-butyric acid ester (PC70BM). Changes in Raman spectra associated with crystallization processes of each component and their impact on Thin Film Morphology were studied during thermal annealing and cooling processes. Transition temperatures to crystalline phases in blends were measured at ∼150 °C and ∼170 °C for DPPTTT and PC70BM, respectively. Such phase changes lead to modifications in local chemical composition reducing relative Raman peak intensities (IPC70BM/IDPPTTT) from ∼0.4 in PC70BM-rich domains to ∼0.15 in homogeneous areas.
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Thin Film Morphology of inkjet printed single droplet organic transistors using polarized raman spectroscopy effect of blending tips pentacene with insulating polymer
ACS Nano, 2011Co-Authors: David James, Iain Mcculloch, B Charlotte K Kjellander, Wiljan T T Smaal, Gerwin H Gelinck, Craig Combe, Richard Wilson, Jeremy H Burroughes, D D C BradleyAbstract:We report Thin-Film Morphology studies of inkjet-printed single-droplet organic Thin-Film transistors (OTFTs) using angle-dependent polarized Raman spectroscopy. We show this to be an effective technique to determine the degree of molecular order as well as to spatially resolve the orientation of the conjugated backbones of the 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pentacene) molecules. The addition of an insulating polymer, polystyrene (PS), does not disrupt the p-p stacking of the TIPS-Pentacene molecules. Blending in fact improves the uniformity of the molecular Morphology and the active layer coverage wiThin the device and reduces the variation in molecular orientation between polycrystalline domains. For OTFT performance, blending enhances the saturation mobility from 0.22 ± 0.05 cm2/ (V·s) (TIPS-Pentacene) to 0.72 ± 0.17 cm2/(V·s) (TIPS-Pentacene:PS) in addition to improving the quality of the interface between TIPS-Pentacene and the gate dielectric in the channel, resulting in threshold voltages of ~0 V and steep subthreshold slopes. © 2011 American Chemical Society.
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influence of blend microstructure on bulk heterojunction organic photovoltaic performance
Chemical Society Reviews, 2011Co-Authors: Christoph J Brabec, Martin Heeney, Iain Mcculloch, Jenny NelsonAbstract:The performance of organic photovoltaic devices based upon bulk heterojunction blends of donor and acceptor materials has been shown to be highly dependent on the Thin Film microstructure. In this tutorial review, we discuss the factors responsible for influencing blend microstructure and how these affect device performance. In particular we discuss how various molecular design approaches can affect the Thin Film Morphology of both the donor and acceptor components, as well as their blend microstructure. We further examine the influence of polymer molecular weight and blend composition upon device performance, and discuss how a variety of processing techniques can be used to control the blend microstructure, leading to improvements in solar cell efficiencies.
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the effect of interfacial roughness on the Thin Film Morphology and charge transport of high performance polythiophenes
Advanced Functional Materials, 2008Co-Authors: Youngsuk Jung, Martin Heeney, Iain Mcculloch, Daniel A. Fischer, Joseph R Kline, Eric K Lin, Dean M. DelongchampAbstract:We control and vary the roughness of a dielectric upon which a high-performance polymer semiconductor, poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (pBTTT) is cast, to determine the effects of roughness on Thin-Film microstructure and the performance of organic field-effect transistors (OFETs). pBTTT forms large, well-oriented terraced domains with high carrier mobility after it is cast upon flat, low-surface-energy substrates and heated to a mesophase. Upon dielectrics with root-mean square (RMS) roughness greater than 0.5 nm, we find significant morphological changes in the pBTTT active layer and significant reductions in its charge carrier mobility. The pBTTT Films on rough dielectrics exhibit significantly less order than those on smooth dielectrics through characterization with atomic force microscopy and X-ray diffraction. This critical RMS roughness implies that there exists a condition at which the pBTTT domains no longer conform to the local nanometer-scale curvature of the substrate.
Harikrishna Erothu - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, thermal processing, and Thin Film Morphology of poly(3-hexylthiophene)-poly(styrenesulfonate) block copolymers
Macromolecules, 2015Co-Authors: Harikrishna Erothu, Joanna Kolomanska, Dargie Deribew, Christine Dagron-lartigau, Priscilla Johnston, Alberto Gregori, Daniel T. W. Toolan, Giuseppe Portale, Stefan Schumann, W BrasAbstract:A series of novel block copolymers, processable from single organic solvents and subsequently rendered amphiphilic by thermolysis, have been synthesized using Grignard metathesis (GRIM) and reversible addition–fragmentation chain transfer (RAFT) polymerizations and azide–alkyne click chemistry. This chemistry is simple and allows the fabrication of well-defined block copolymers with controllable block lengths. The block copolymers, designed for use as interfacial adhesive layers in organic photovoltaics to enhance contact between the photoactive and hole transport layers, comprise printable poly(3-hexylthiophene)-block-poly(neopentyl p-styrenesulfonate), P3HT-b-PNSS. Subsequently, they are converted to P3HT-b-poly(p-styrenesulfonate), P3HT-b-PSS, following deposition and thermal treatment at 150 °C. Grazing incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS) revealed that Thin Films of the amphiphilic block copolymers comprise lamellar nanodomains of P3HT crystallites that can be pushed further apart by increasing the PSS block lengths. The approach of using a thermally modifiable block allows deposition of this copolymer from a single organic solvent and subsequent conversion to an amphiphilic layer by nonchemical means, particularly attractive to large scale roll-to-roll industrial printing processes.
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Synthesis, thermal processing, and Thin Film Morphology of poly(3-hexylthiophene)-poly(styrenesulfonate) block copolymers
Macromolecules, 2015Co-Authors: Harikrishna Erothu, Joanna Kolomanska, Dargie Deribew, Priscilla Johnston, Alberto Gregori, Daniel T. W. Toolan, Giuseppe Portale, Stefan Schumann, Christine Lartigau-dagron, W BrasAbstract:A series of novel block copolymers, processable from single organic solvents and subsequently rendered amphiphilic by thermolysis, have been synthesized using Grignard metathesis (GRIM) and reversible addition-fragmentation chain transfer (RAFT) polymerizations and azide-alkyne click chemistry. This chemistry is simple and allows the fabrication of well-defined block copolymers with controllable block lengths. The block copolymers, designed for use as interfacial adhesive layers in organic photovoltaics to enhance contact between the photoactive and hole transport layers, comprise printable poly(3-hexylthiophene)-block-poly(neopentyl p-styrenesulfonate), P3HT-b-PNSS. Subsequently, they are converted to P3HT-b-poly(p-styrenesulfonate), P3HT-b-PSS, following deposition and thermal treatment at 150 °C. Grazing incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS) revealed that Thin Films of the amphiphilic block copolymers comprise lamellar nanodomains of P3HT crystallites that can be pushed further apart by increasing the PSS block lengths. The approach of using a thermally modifiable block allows deposition of this copolymer from a single organic solvent and subsequent conversion to an amphiphilic layer by nonchemical means, particularly attractive to large scale roll-to-roll industrial printing processes. © 2015 American Chemical Society.
Dean M. Delongchamp - One of the best experts on this subject based on the ideXlab platform.
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Effect of Solution Shearing Method on Packing and Disorder of Organic Semiconductor Polymers
Chemistry of Materials, 2015Co-Authors: Gaurav Giri, Dean M. Delongchamp, Julia Reinspach, Daniel A. Fischer, Lee J. Richter, Stephanie J. Benight, Alexander L. Ayzner, Lei FangAbstract:The solution shearing method has previously been used to tune the molecular packing and crystal Thin Film Morphology of small molecular organic semiconductors (OSCs). Here, we study how the solution shearing method impacts the Thin Film Morphology and causes structural rearrangements of two polymeric OSCs with interdigitated side chain packing, namely P2TDC17FT4 and PBTTT-C16. The conjugated backbone tilt angle and the Thin Film Morphology of the P2TDC17FT4 polymer were changed by the solution shearing conditions, and an accompanying change in the charge carrier mobility was observed. For PBTTT-C16, the out-of-plane lamellar spacing was increased by solution shearing, due to increased disorder of side chains. The ability to induce structural rearrangement of polymers through solution shearing allows for an easy and alternative method to modify OSC charge transport properties.
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the effect of interfacial roughness on the Thin Film Morphology and charge transport of high performance polythiophenes
Advanced Functional Materials, 2008Co-Authors: Youngsuk Jung, Martin Heeney, Iain Mcculloch, Daniel A. Fischer, Joseph R Kline, Eric K Lin, Dean M. DelongchampAbstract:We control and vary the roughness of a dielectric upon which a high-performance polymer semiconductor, poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (pBTTT) is cast, to determine the effects of roughness on Thin-Film microstructure and the performance of organic field-effect transistors (OFETs). pBTTT forms large, well-oriented terraced domains with high carrier mobility after it is cast upon flat, low-surface-energy substrates and heated to a mesophase. Upon dielectrics with root-mean square (RMS) roughness greater than 0.5 nm, we find significant morphological changes in the pBTTT active layer and significant reductions in its charge carrier mobility. The pBTTT Films on rough dielectrics exhibit significantly less order than those on smooth dielectrics through characterization with atomic force microscopy and X-ray diffraction. This critical RMS roughness implies that there exists a condition at which the pBTTT domains no longer conform to the local nanometer-scale curvature of the substrate.
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Microstructure of Oligofluorene Asymmetric Derivatives in Organic Thin Film Transistors
Chemistry of Materials, 2008Co-Authors: Quan Yuan, Stefan C B Mannsfeld, Ming Lee Tang, Mark E Roberts, Dean M. Delongchamp, Michael F. Toney, Zhenan BaoAbstract:In organic Thin Film transistors (OTFT), modifying the molecular chemical structure affects the molecular packing and Thin Film Morphology, which both sensitively influence the charge carrier mobility. A detailed understanding of the interplay of molecular chemical structure, molecular packing, and Thin Film Morphology is therefore necessary to improve OTFT performance. Fluorene-bithiophene-fluorene (FTTF) derivatives have demonstrated great potential for use as the active layer for OTFTs. A series of FTTF asymmetrically substituted derivatives were synthesized to fine-tune the Film properties. In this study, the Thin Film microstructure details of FTTF and several FTTF derivatives with asymmetrically substituted alkyl-chains of different lengths are studied and compared with their electrical performance in Thin Film transistor devices. The respective unit cells were characterized using grazing incidence X-ray diffraction (GIXD), and for FTTF the detailed molecular packing was determined from the GIXD int...