339 results found
Hallani RK, Moser M, Bristow H, et al., 2019, A low temperature crosslinking benzocyclobutene based polymer dielectric for organic thin film transistors on plastic substrates., J Org Chem
The synthesis of a new benzocyclobutene based polymer, PSBBB, as dielectric material for organic thin film transistors was reported. Compared to conventional benzocyclobutene based materials, the introduction of a butoxide substituent at the 7-position of the benzocyclobutene subunit allowed PSBBB to be crosslinked at temperatures of 120 °C, thus rendering it compatible with the processing conditions incurred by flexible plastic substrates. The crosslinking behavior of PSBBB was investigated by Fourier transform-infrared spectroscopy and differential scanning calorimetry, demonstrating crosslinking of the polymer after curing at 120 °C. Bottom-gate bottom-contact organic thin film transistors were fabricated using PSBBB as dielectric, affording a comparable performance to other dielectric polymeric materials.
Chen H, Wadsworth A, Ma C, et al., 2019, The Effect of Ring Expansion in Thienobenzo[b]indacenodithiophene Polymers for Organic Field-Effect Transistors., J Am Chem Soc, Vol: 141, Pages: 18806-18813
A fused donor, thienobenzo[b]indacenodithiophene (TBIDT), was designed and synthesized using a novel acid-promoted cascade ring closure strategy, and then copolymerized with a benzothiadiazole (BT) monomer. The backbone of TBIDT is an expansion of the well-known indacenodithiophene (IDT) unit and was expected to enhance the charge carrier mobility by improving backbone planarity and facilitating short contacts between polymer chains. However, the optimized field-effect transistors demonstrated an average saturation hole mobility of 0.9 cm2 V-1 s-1, lower than the performance of IDT-BT (∼1.5 cm2 V-1 s-1). Mobilities extracted from time-resolved microwave conductivity measurements were consistent with the trend in hole mobilities in organic field-effect transistor devices. Scanning tunneling microscopy measurements and computational modeling illustrated that TBIDT-BT exhibits a less ordered microstructure in comparison to IDT-BT. This reveals that a regular side-chain packing density, independent of conformational isomers, is critical to avoid local free volume due to irregular packing, which can host trapping impurities. DFT calculations indicated that TBIDT-BT, despite containing a larger, planar unit, showed less stabilization of planar backbone geometries in comparison to IDT-BT. This is due to the reduced electrostatic stabilizing interactions between the peripheral thiophene of the fused core and the BT unit, resulting in a reduction of the barrier to rotation around the single bond. These insights provide a greater understanding of the general structure-property relationships required for semiconducting polymer repeat units to ensure optimal backbone planarization, as illustrated with IDT-type units, guiding the design of novel semiconducting polymers with extended fused backbones for high-performance field-effect transistors.
Li Z, Li H, Jiang K, et al., 2019, Self-Powered Perovskite/CdS Heterostructure Photodetectors, ACS APPLIED MATERIALS & INTERFACES, Vol: 11, Pages: 40204-40213, ISSN: 1944-8244
Yarali E, Koutsiaki C, Faber H, et al., 2019, Recent Progress in Photonic Processing of Metal-Oxide Transistors, ADVANCED FUNCTIONAL MATERIALS, ISSN: 1616-301X
He Q, Shahid M, Wu J, et al., 2019, Fused Cyclopentadithienothiophene acceptor enables ultrahigh short‐circuit current and high efficiency >11% in as‐cast organic solar cells, Advanced Functional Materials, Vol: 29, Pages: 1-7, ISSN: 1616-301X
A new method to synthesize an electron‐rich building block cyclopentadithienothiophene (9H‐thieno‐[3,2‐b]thieno[2″,3″:4′,5′]thieno[2′,3′:3,4]cyclopenta[1,2‐d]thiophene, CDTT) via a facile aromatic extension strategy is reported. By combining CDTT with 1,1‐dicyanomethylene‐3‐indanone endgroups, a promising nonfullerene small molecule acceptor (CDTTIC) is prepared. As‐cast, single‐junction nonfullerene organic solar cells based on PFBDB‐T: CDTTIC blends exhibit very high short‐circuit currents up to 26.2 mA cm−2 in combination with power conversion efficiencies over 11% without any additional processing treatments. The high photocurrent results from the near‐infrared absorption of the CDTTIC acceptor and the well‐intermixed blend morphology of polymer donor PFBDB‐T and CDTTIC. This work demonstrates a useful fused ring extension strategy and promising solar cell results, indicating the great potential of the CDTT derivatives as electron‐rich building blocks for constructing high‐performance small molecule acceptors in organic solar cells.
Lin Y-H, Huang W, Pattanasattayavong P, et al., 2019, Deciphering photocarrier dynamics for tuneable high-performance perovskite-organic semiconductor heterojunction phototransistors, NATURE COMMUNICATIONS, Vol: 10, ISSN: 2041-1723
Anthopoulos TD, 2019, Ultrathin channels make transistors go faster, NATURE MATERIALS, Vol: 18, Pages: 1033-1034, ISSN: 1476-1122
Lin Y, Adilbekova B, Firdaus Y, et al., 2019, 17% Efficient Organic Solar Cells Based on Liquid Exfoliated WS2 as a Replacement for PEDOT:PSS, ADVANCED MATERIALS, ISSN: 0935-9648
Seitkhan A, Neophytou M, Kirkus M, et al., 2019, Use of the Phen-NaDPO:Sn(SCN)(2) Blend as Electron Transport Layer Results to Consistent Efficiency Improvements in Organic and Hybrid Perovskite Solar Cells, ADVANCED FUNCTIONAL MATERIALS, ISSN: 1616-301X
Panidi J, Kainth J, Paterson AF, et al., 2019, Introducing a nonvolatile N-type dopant drastically improves electron transport in polymer and small-molecule organic transistors, Advanced Functional Materials, Vol: 29, Pages: 1-10, ISSN: 1616-301X
KGaA, Weinheim Molecular doping is a powerful yet challenging technique for enhancing charge transport in organic semiconductors (OSCs). While there is a wealth of research on p-type dopants, work on their n-type counterparts is comparatively limited. Here, reported is the previously unexplored n-dopant (12a,18a)-5,6,12,12a,13,18,18a,19-octahydro-5,6-dimethyl- 13,18[1′,2′]-benzenobisbenzimidazo [1,2-b:2′,1′-d]benzo[i][2.5]benzodiazo-cine potassium triflate adduct (DMBI-BDZC) and its application in organic thin-film transistors (OTFTs). Two different high electron mobility OSCs, namely, the polymer poly[[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8- bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2′-bithiophene)] and a small-molecule naphthalene diimides fused with 2-(1,3-dithiol-2-ylidene)malononitrile groups (NDI-DTYM2) are used to study the effectiveness of DMBI-BDZC as a n-dopant. N-doping of both semiconductors results in OTFTs with improved electron mobility (up to 1.1 cm2 V−1 s−1), reduced threshold voltage and lower contact resistance. The impact of DMBI-BDZC incorporation is particularly evident in the temperature dependence of the electron transport, where a significant reduction in the activation energy due to trap deactivation is observed. Electron paramagnetic resonance measurements support the n-doping activity of DMBI-BDZC in both semiconductors. This finding is corroborated by density functional theory calculations, which highlights ground-state electron transfer as the main doping mechanism. The work highlights DMBI-BDZC as a promising n-type molecular dopant for OSCs and its application in OTFTs, solar cells, photodetectors, and thermoelectrics.
Zheng X, Troughton J, Gasparini N, et al., 2019, Quantum Dots Supply Bulk- and Surface-Passivation Agents for Efficient and Stable Perovskite Solar Cells, JOULE, Vol: 3, Pages: 1963-1976, ISSN: 2542-4351
Lin Y, Yu L, Xia Y, et al., 2019, One-Step Blade-Coated Highly Efficient Nonfullerene Organic Solar Cells with a Self-Assembled Interfacial Layer Enabled by Solvent Vapor Annealing, SOLAR RRL, Vol: 3, ISSN: 2367-198X
Khan JI, Ashraf RS, Alamoudi MA, et al., 2019, P3HT Molecular Weight Determines the Performance of P3HT:O-IDTBR Solar Cells, SOLAR RRL, Vol: 3, ISSN: 2367-198X
Wu Y, Li M, Wahyudi W, et al., 2019, Performance and Stability Improvement of Layered NCM Lithium-Ion Batteries at High Voltage by a Microporous Al2O3 Sol-Gel Coating, ACS OMEGA, Vol: 4, Pages: 13972-13980, ISSN: 2470-1343
Ma C, Liu C, Huang J, et al., 2019, Plasmonic-Enhanced Light Harvesting and Perovskite Solar Cell Performance Using Au Biometric Dimers with Broadband Structural Darkness, SOLAR RRL, Vol: 3, ISSN: 2367-198X
Paterson AF, Faber H, Savva A, et al., On the Role of Contact Resistance and Electrode Modification in Organic Electrochemical Transistors., Adv Mater, Pages: e1902291-e1902291
Contact resistance is renowned for its unfavorable impact on transistor performance. Despite its notoriety, the nature of contact resistance in organic electrochemical transistors (OECTs) remains unclear. Here, by investigating the role of contact resistance in n-type OECTs, the first demonstration of source/drain-electrode surface modification for achieving state-of-the-art n-type OECTs is reported. Specifically, thiol-based self-assembled monolayers (SAMs), 4-methylbenzenethiol (MBT) and pentafluorobenzenethiol (PFBT), are used to investigate contact resistance in n-type accumulation-mode OECTs made from the hydrophilic copolymer P-90, where the deliberate functionalization of the gold source/drain electrodes decreases and increases the energetic mismatch at the electrode/semiconductor interface, respectively. Although MBT treatment is found to increase the transconductance three-fold, contact resistance is not found to be the dominant factor governing OECT performance. Additional morphology and surface energy investigations show that increased performance comes from SAM-enhanced source/drain electrode surface energy, which improves wetting, semiconductor/metal interface quality, and semiconductor morphology at the electrode and channel. Overall, contact resistance in n-type OECTs is investigated, whilst identifying source/drain electrode treatment as a useful device engineering strategy for achieving state of the art n-type OECTs.
Bristow H, Thorley KJ, White AJP, et al., Impact of Nonfullerene Acceptor Side Chain Variation on Transistor Mobility, ADVANCED ELECTRONIC MATERIALS, ISSN: 2199-160X
Karuthedath S, Firdaus Y, Liang R-Z, et al., 2019, Impact of Fullerene on the Photophysics of Ternary Small Molecule Organic Solar Cells, ADVANCED ENERGY MATERIALS, Vol: 9, ISSN: 1614-6832
Bottacchi F, Bottacchi S, Anthopoulos TD, 2019, A novel method for surface coverage spectroscopy with atomic force microscope: theory, modeling and experimental results for cylindrical nanostructures
A novel method for measuring the surface coverage of randomly distributedcylindrical nanoparticles such as nanorods and nanowires, using atomic forcemicroscopy (AFM), is presented. The method offers several advantages overexisting techniques such as particle beam and x-ray diffraction spectroscopy.These include, subnanometer vertical and lateral resolution, non destructiveinteraction with the sample surface allowing repeated measurements,user-friendly setup and ambient operating conditions. The method relies on theuse of a statistical model to describe the variations of the nanoparticlesaggregates height as a function of x,y position on the sample surface measuredby AFM. To verify the validity of the method we studied two types of randomlyoriented networks of carbon nanotubes (CNTs) and silver nanowires (Ag NWs) bothprocessed from solution phase. Experimental results are found to be inexcellent agreement with model predictions whilst analysis of the measuredsurface height density, together with the nanoparticle diameter statisticaldistribution, allow the extraction of the coverage coefficients for alldetected nanoparticle aggregates as well as for the total surface coverage. Themethod can be seen as a new powerful tool for the quantitative surface coverageanalysis of arbitrary nanoscale systems.
Khim D, Lin Y-H, Anthopoulos TD, 2019, Impact of Layer Configuration and Doping on Electron Transport and Bias Stability in Heterojunction and Superlattice Metal Oxide Transistors, ADVANCED FUNCTIONAL MATERIALS, Vol: 29, ISSN: 1616-301X
Georgiadou DG, Lin Y, Lim J, et al., 2019, High Responsivity and Response Speed Single‐Layer Mixed‐Cation Lead Mixed‐Halide Perovskite Photodetectors Based on Nanogap Electrodes Manufactured on Large‐Area Rigid and Flexible Substrates, Advanced Functional Materials, Vol: 29, Pages: 1901371-1901371, ISSN: 1616-301X
Choi HH, Paterson AF, Fusella MA, et al., Hall Effect in Polycrystalline Organic Semiconductors: The Effect of Grain Boundaries, ADVANCED FUNCTIONAL MATERIALS, ISSN: 1616-301X
Tang M-C, Barrit D, Munir R, et al., 2019, Bismuth-Based Perovskite-Inspired Solar Cells: In Situ Diagnostics Reveal Similarities and Differences in the Film Formation of Bismuth- and Lead-Based Films, SOLAR RRL, Vol: 3, ISSN: 2367-198X
Chaudhry MU, Wang N, Tetzner K, et al., 2019, Light-Emitting Transistors Based on Solution-Processed Heterostructures of Self-Organized Multiple-Quantum-Well Perovskite and Metal-Oxide Semiconductors, ADVANCED ELECTRONIC MATERIALS, Vol: 5, ISSN: 2199-160X
Twyman N, Tetzner K, Anthopoulos T, et al., 2019, Rapid photonic curing of solution-processed In2O3 layers on flexible substrates, Applied Surface Science, Vol: 479, Pages: 974-979, ISSN: 0169-4332
In2O3 is one of the most important semiconducting metal oxides primarily because of its wide band gap, high electron mobility and processing versatility. To this end, high-quality thin films of In2O3 can be prepared using scalable and inexpensive solution-based deposition methods, hence making it attractive for application in a number of emerging electronic applications. However, traditional solution processing often requires high temperature and lengthy annealing steps, making it impossible to use in combination with temperature-sensitive plastic substrates, which would be desired for numerous emerging flexible device applications. Here, rapid photonic curing of In2O3 layers is explored as an alternative to thermal annealing. Oxide thin films are successfully prepared on a range of substrates, including glass, polyimide, and polyethylene naphthalate. The effect of substrate and post-processing treatment on the morphology, surface chemistry, and electronic properties is investigated by atomic force microscopy and X-ray photoelectron spectroscopy. Systematic trends are identified, particularly in the degree of conversion of the precursor and its influence on the electronic structure.
He Q, Shahid M, Panidi J, et al., 2019, A versatile star-shaped organic semiconductor based on benzodithiophene and diketopyrrolopyrrole, Journal of Materials Chemistry C, Vol: 7, Pages: 6622-6629, ISSN: 2050-7526
We report the synthesis of a new star-shaped π-conjugated oligomer, BDT(DPP)4, containing a benzodithiophene core and four diketopyrrolopyrrole arms. The thermal, electrochemical and optical properties are characterized and the results complemented by computational studies. The utility of the molecule is demonstrated in both solar cell and field-effect transistor devices. In the former, BDT(DPP)4 displays low efficiency when used as an acceptor in blends with poly(3-hexylthiophene) but exhibits promising performance as a donor, in blends with either a fullerene or a non-fullerene acceptor. In field-effect transistors BDT(DPP)4 exhibits typical p-type transistor behavior, which is in accordance with its better donor performance in solar cell devices.
Wang K, Neophytou M, Aydin E, et al., 2019, Triarylphosphine Oxide as Cathode Interfacial Material for Inverted Perovskite Solar Cells, ADVANCED MATERIALS INTERFACES, Vol: 6, ISSN: 2196-7350
Paterson AF, Tsetseris L, Li R, et al., 2019, Addition of the lewis acid Zn(C6 F5 )2 enables organic transistors with a maximum hole mobility in excess of 20 cm2 V-1 s-1, Advanced Materials, Vol: 31, ISSN: 0935-9648
Incorporating the molecular organic Lewis acid tris(pentafluorophenyl)borane [B(C6 F5 )3 ] into organic semiconductors has shown remarkable promise in recent years for controlling the operating characteristics and performance of various opto/electronic devices, including, light-emitting diodes, solar cells, and organic thin-film transistors (OTFTs). Despite the demonstrated potential, however, to date most of the work has been limited to B(C6 F5 )3 with the latter serving as the prototypical air-stable molecular Lewis acid system. Herein, the use of bis(pentafluorophenyl)zinc [Zn(C6 F5 )2 ] is reported as an alternative Lewis acid additive in high-hole-mobility OTFTs based on small-molecule:polymer blends comprising 2,7-dioctylbenzothieno [3,2-b]benzothiophene and indacenodithiophene-benzothiadiazole. Systematic analysis of the materials and device characteristics supports the hypothesis that Zn(C6 F5 )2 acts simultaneously as a p-dopant and a microstructure modifier. It is proposed that it is the combination of these synergistic effects that leads to OTFTs with a maximum hole mobility value of 21.5 cm2 V-1 s-1 . The work not only highlights Zn(C6 F5 )2 as a promising new additive for next-generation optoelectronic devices, but also opens up new avenues in the search for high-mobility organic semiconductors.
Firdaus Y, Le Corre VM, Khan JI, et al., 2019, Key Parameters Requirements for Non-Fullerene-Based Organic Solar Cells with Power Conversion Efficiency > 20%, ADVANCED SCIENCE, Vol: 6, ISSN: 2198-3844
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