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Conformational Analysis of Conjugated Organic Materials: What Are My Heteroatoms Really Doing? Chempluschem 2024:e202300773. [PMID: 38598306 DOI: 10.1002/cplu.202300773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/20/2024] [Indexed: 04/12/2024]
Abstract
Organic semiconductor small molecules and polymers often incorporate heteroatoms into their chemical structures to affect the electronic properties of the material. A particular design philosophy has been to use these heteroatoms to influence torsional potentials, since the overlap of adjacent π-orbitals is most efficient in planar systems and is critical for charge delocalization in these systems. Since these design rules became popular, the messages from the earlier works have become lost in a sea of reports of "conformational locks", where the non-covalent interactions have relatively small contributions to planarizing torsional potentials. Greater influences can be found in the stabilization by extended conjugation, consideration of steric repulsion, and the interactions involving solubilizing chains and neighboring molecules or polymer chains in condensed phases.
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Single-Component Electroactive Polymer Architectures for Non-Enzymatic Glucose Sensing. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2308281. [PMID: 38520718 DOI: 10.1002/advs.202308281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/12/2024] [Indexed: 03/25/2024]
Abstract
Organic mixed ionic-electronic conductors (OMIECs) have emerged as promising materials for biological sensing, owing to their electrochemical activity, stability in an aqueous environment, and biocompatibility. Yet, OMIEC-based sensors rely predominantly on the use of composite matrices to enable stimuli-responsive functionality, which can exhibit issues with intercomponent interfacing. In this study, an approach is presented for non-enzymatic glucose detection by harnessing a newly synthesized functionalized monomer, EDOT-PBA. This monomer integrates electrically conducting and receptor moieties within a single organic component, obviating the need for complex composite preparation. By engineering the conditions for electrodeposition, two distinct polymer film architectures are developed: pristine PEDOT-PBA and molecularly imprinted PEDOT-PBA. Both architectures demonstrated proficient glucose binding and signal transduction capabilities. Notably, the molecularly imprinted polymer (MIP) architecture demonstrated faster stabilization upon glucose uptake while it also enabled a lower limit of detection, lower standard deviation, and a broader linear range in the sensor output signal compared to its non-imprinted counterpart. This material design not only provides a robust and efficient platform for glucose detection but also offers a blueprint for developing selective sensors for a diverse array of target molecules, by tuning the receptor units correspondingly.
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Peculiar transient behaviors of organic electrochemical transistors governed by ion injection directionality. Nat Commun 2023; 14:7577. [PMID: 38016963 PMCID: PMC10684893 DOI: 10.1038/s41467-023-42840-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 10/24/2023] [Indexed: 11/30/2023] Open
Abstract
Despite the growing interest in dynamic behaviors at the frequency domain, there exist very few studies on molecular orientation-dependent transient responses of organic mixed ionic-electronic conductors. In this research, we investigated the effect of ion injection directionality on transient electrochemical transistor behaviors by developing a model mixed conductor system. Two polymers with similar electrical, ionic, and electrochemical characteristics but distinct backbone planarities and molecular orientations were successfully synthesized by varying the co-monomer unit (2,2'-bithiophene or phenylene) in conjunction with a novel 1,4-dithienylphenylene-based monomer. The comprehensive electrochemical analysis suggests that the molecular orientation affects the length of the ion-drift pathway, which is directly correlated with ion mobility, resulting in peculiar OECT transient responses. These results provide the general insight into molecular orientation-dependent ion movement characteristics as well as high-performance device design principles with fine-tuned transient responses.
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Interplay between Side Chain Density and Polymer Alignment: Two Competing Strategies for Enhancing the Thermoelectric Performance of P3HT Analogues. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:9029-9039. [PMID: 38027547 PMCID: PMC10653083 DOI: 10.1021/acs.chemmater.3c01680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/06/2023] [Indexed: 12/01/2023]
Abstract
A series of polythiophenes with varying side chain density was synthesized, and their electrical and thermoelectric properties were investigated. Aligned and non-aligned thin films of the polymers were characterized in the neutral and chemically doped states. Optical and diffraction measurements revealed an overall lower order in the thin films with lower side chain density, also confirmed using polarized optical experiments on aligned thin films. However, upon doping the non-aligned films, a sixfold increase in electrical conductivity was observed for the polythiophene with the lowest side chain density compared to poly(3-hexylthiophene) (P3HT). We found that the improvement in conductivity was not due to a larger charge carrier density but an increase in charge carrier mobility after doping with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). On the other hand, doped aligned films did not show the same trend; lower side chain density instead led to a lower conductivity and Seebeck coefficient compared to those for P3HT. This was attributed to the poorer alignment of the polymer thin films with lower side chain density. The study demonstrates that optimizing side chain density is a synthetically simple and effective way to improve electrical conductivity in polythiophene films relevant to thermoelectric applications.
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Quinoxaline derivatives as attractive electron-transporting materials. Beilstein J Org Chem 2023; 19:1694-1712. [PMID: 38025084 PMCID: PMC10644009 DOI: 10.3762/bjoc.19.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/03/2023] [Indexed: 12/01/2023] Open
Abstract
This review article provides a comprehensive overview of recent advancements in electron transport materials derived from quinoxaline, along with their applications in various electronic devices. We focus on their utilization in organic solar cells (OSCs), dye-sensitized solar cells (DSSCs), organic field-effect transistors (OFETs), organic-light emitting diodes (OLEDs) and other organic electronic technologies. Notably, the potential of quinoxaline derivatives as non-fullerene acceptors in OSCs, auxiliary acceptors and bridging materials in DSSCs, and n-type semiconductors in transistor devices is discussed in detail. Additionally, their significance as thermally activated delayed fluorescence emitters and chromophores for OLEDs, sensors and electrochromic devices is explored. The review emphasizes the remarkable characteristics and versatility of quinoxaline derivatives in electron transport applications. Furthermore, ongoing research efforts aimed at enhancing their performance and addressing key challenges in various applications are presented.
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The Influence of Regiochemistry on the Performance of Organic Mixed Ionic and Electronic Conductors. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202304390. [PMID: 38528843 PMCID: PMC10962556 DOI: 10.1002/ange.202304390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Indexed: 03/27/2024]
Abstract
Thiophenes functionalised in the 3-position are ubiquitous building blocks for the design and synthesis of organic semiconductors. Their non-centrosymmetric nature has long been used as a powerful synthetic design tool exemplified by the vastly different properties of regiorandom and regioregular poly(3-hexylthiophene) owing to the repulsive head-to-head interactions between neighbouring side chains in the regiorandom polymer. The renewed interest in highly electron-rich 3-alkoxythiophene based polymers for bioelectronic applications opens up new considerations around the regiochemistry of these systems as both the head-to-tail and head-to-head couplings adopt near-planar conformations due to attractive intramolecular S-O interactions. To understand how this increased flexibility in the molecular design can be used advantageously, we explore in detail the geometrical and electronic effects that influence the optical, electrochemical, structural, and electrical properties of a series of six polythiophene derivatives with varying regiochemistry and comonomer composition. We show how the interplay between conformational disorder, backbone coplanarity and polaron distribution affects the mixed ionic-electronic conduction. Ultimately, we use these findings to identify a new conformationally restricted polythiophene derivative for p-type accumulation-mode organic electrochemical transistor applications with performance on par with state-of-the-art mixed conductors evidenced by a μC* product of 267 F V-1 cm-1 s-1.
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7
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The Influence of Regiochemistry on the Performance of Organic Mixed Ionic and Electronic Conductors. Angew Chem Int Ed Engl 2023; 62:e202304390. [PMID: 37204070 PMCID: PMC10962546 DOI: 10.1002/anie.202304390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/11/2023] [Accepted: 05/17/2023] [Indexed: 05/20/2023]
Abstract
Thiophenes functionalised in the 3-position are ubiquitous building blocks for the design and synthesis of organic semiconductors. Their non-centrosymmetric nature has long been used as a powerful synthetic design tool exemplified by the vastly different properties of regiorandom and regioregular poly(3-hexylthiophene) owing to the repulsive head-to-head interactions between neighbouring side chains in the regiorandom polymer. The renewed interest in highly electron-rich 3-alkoxythiophene based polymers for bioelectronic applications opens up new considerations around the regiochemistry of these systems as both the head-to-tail and head-to-head couplings adopt near-planar conformations due to attractive intramolecular S-O interactions. To understand how this increased flexibility in the molecular design can be used advantageously, we explore in detail the geometrical and electronic effects that influence the optical, electrochemical, structural, and electrical properties of a series of six polythiophene derivatives with varying regiochemistry and comonomer composition. We show how the interplay between conformational disorder, backbone coplanarity and polaron distribution affects the mixed ionic-electronic conduction. Ultimately, we use these findings to identify a new conformationally restricted polythiophene derivative for p-type accumulation-mode organic electrochemical transistor applications with performance on par with state-of-the-art mixed conductors evidenced by a μC* product of 267 F V-1 cm-1 s-1 .
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8
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Aqueous processing of organic semiconductors enabled by stable nanoparticles with built-in surfactants. NANOSCALE 2023; 15:6793-6801. [PMID: 36946985 DOI: 10.1039/d2nr06024h] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The introduction of oligoether side chains onto a polymer backbone can help to stabilise polymeric dispersions in water without the necessity of surfactants or additives when conjugated polymer nanoparticles are prepared. A series of poly(3-hexylthiophene) (P3HT) derivatives with different content of a polar thiophene derivative 3-((2-methoxyethoxy)methyl)thiophene was interrogated to find the effect of the polar chains on the stability of the formed nanoparticles, as well as their structural, optical, electrochemical, and electrical properties. Findings indicated that incorporation of 10-20 percent of the polar side chain led to particles that are stable over a period of 42 days, with constant particle size and polydispersity, however the particles from the polymer with 30 percent polar side chain showed aggregation effects. The polymer dispersions showed a stronger solid-like behaviour in water with decreasing polar side chain content, while thin film deposition from water was found to afford globular morphologies and crystallites with more isotropic orientation compared to conventional solution-processed films. As a proof-of-principle, field-effect transistors were fabricated directly from the aqueous dispersions demonstrating that polymers with hydrophilic moieties can be processed in water without the requirement of surfactants.
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9
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Highly Efficient Mixed Conduction in a Fused Oligomer n-Type Organic Semiconductor Enabled by 3D Transport Pathways. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2300252. [PMID: 36918256 DOI: 10.1002/adma.202300252] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/23/2023] [Indexed: 05/17/2023]
Abstract
Tailoring organic semiconductors to facilitate mixed conduction of ionic and electronic charges when interfaced with an aqueous media has spurred many recent advances in organic bioelectronics. The field is still restricted, however, by very few n-type (electron-transporting) organic semiconductors with adequate performance metrics. Here, a new electron-deficient, fused polycyclic aromatic system, TNR, is reported with excellent n-type mixed conduction properties including a µC* figure-of-merit value exceeding 30 F cm-1 V-1 s-1 for the best performing derivative. Comprising three naphthalene bis-isatin moieties, this new molecular design builds on successful small-molecule mixed conductors; by extending the molecular scaffold into the oligomer domain, good film-forming properties, strong π-π interactions, and consequently excellent charge-transport properties are obtained. Through judicious optimization of the side chains, the linear oligoether and branched alkyl chain derivative bgTNR is obtained which shows superior mixed conduction in an organic electrochemical transistor configuration including an electron mobility around 0.3 cm2 V-1 s-1 . By optimizing the side chains, the dominant molecular packing can be changed from a preferential edge-on orientation (with high charge-transport anisotropy) to an oblique orientation that can support 3D transport pathways which in turn ensure highly efficient mixed conduction properties across the bulk semiconductor film.
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10
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Resolving the backbone tilt of crystalline poly(3-hexylthiophene) with resonant tender X-ray diffraction. MATERIALS HORIZONS 2022; 9:1649-1657. [PMID: 35421883 DOI: 10.1039/d2mh00244b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The way in which conjugated polymers pack in the solid state strongly affects the performance of polymer-based optoelectronic devices. However, even for the most crystalline conjugated polymers the precise packing of chains within the unit cell is not well established. Here we show that by performing resonant X-ray diffraction experiments at the sulfur K-edge we are able to resolve the tilting of the planar backbones of crystalline poly(3-hexylthiophene) (P3HT) within the unit cell. This approach exploits the anisotropic nature of the X-ray optical properties of conjugated polymers, enabling us to discern between different proposed crystal structures. By comparing our data with simulations based on different orientations, a tilting of the planar conjugated backbone with respect to the side chain stacking direction of 30 ± 5° is determined.
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11
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High-Efficiency Ion-Exchange Doping of Conducting Polymers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2102988. [PMID: 34418878 DOI: 10.1002/adma.202102988] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Molecular doping-the use of redox-active small molecules as dopants for organic semiconductors-has seen a surge in research interest driven by emerging applications in sensing, bioelectronics, and thermoelectrics. However, molecular doping carries with it several intrinsic problems stemming directly from the redox-active character of these materials. A recent breakthrough was a doping technique based on ion-exchange, which separates the redox and charge compensation steps of the doping process. Here, the equilibrium and kinetics of ion exchange doping in a model system, poly(2,5-bis(3-alkylthiophen-2-yl)thieno(3,2-b)thiophene) (PBTTT) doped with FeCl3 and an ionic liquid, is studied, reaching conductivities in excess of 1000 S cm-1 and ion exchange efficiencies above 99%. Several factors that enable such high performance, including the choice of acetonitrile as the doping solvent, which largely eliminates electrolyte association effects and dramatically increases the doping strength of FeCl3 , are demonstrated. In this high ion exchange efficiency regime, a simple connection between electrochemical doping and ion exchange is illustrated, and it is shown that the performance and stability of highly doped PBTTT is ultimately limited by intrinsically poor stability at high redox potential.
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12
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From p- to n-Type Mixed Conduction in Isoindigo-Based Polymers through Molecular Design. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107829. [PMID: 35075720 DOI: 10.1002/adma.202107829] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Organic mixed ionic and electronic conductors are of significant interest for bioelectronic applications. Here, three different isoindigoid building blocks are used to obtain polymeric mixed conductors with vastly different structural and electronic properties which can be further fine-tuned through the choice of comonomer unit. This work shows how careful design of the isoindigoid scaffold can afford highly planar polymer structures with high degrees of electronic delocalization, while subtle structural modifications can control the dominant charge carrier (hole or electron) when probed in organic electrochemical transistors. A combination of experimental and computational techniques is employed to probe electrochemical, structural, and mixed ionic and electronic properties of the polymer series which in turn allows the derivation of important structure-property relations for this promising class of materials in the context of organic bioelectronics. Ultimately, these findings are used to outline robust molecular-design strategies for isoindigo-based mixed conductors that can support efficient p-type, n-type, and ambipolar transistor operation in an aqueous environment.
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Quantitative Insights into the Adsorption Structure of Diindeno[1,2- a;1',2'- c]fluorene-5,10,15-trione (Truxenone) on a Cu(111) Surface Using X-ray Standing Waves. ACS OMEGA 2021; 6:34525-34531. [PMID: 34963937 PMCID: PMC8697368 DOI: 10.1021/acsomega.1c04799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
The adsorption structure of truxenone on Cu(111) was determined quantitatively using normal-incidence X-ray standing waves. The truxenone molecule was found to chemisorb on the surface, with all adsorption heights of the dominant species on the surface less than ∼2.5 Å. The phenyl backbone of the molecule adsorbs mostly parallel to the underlying surface, with an adsorption height of 2.32 ± 0.08 Å. The C atoms bound to the carbonyl groups are located closer to the surface at 2.15 ± 0.10 Å, a similar adsorption height to that of the chemisorbed O species; however, these O species were found to adsorb at two different adsorption heights, 1.96 ± 0.08 and 2.15 ± 0.06 Å, at a ratio of 1:2, suggesting that on average, one O atom per adsorbed truxenone molecule interacts more strongly with the surface. The adsorption geometry determined herein is an important benchmark for future theoretical calculations concerning both the interaction with solid surfaces and the electronic properties of a molecule with electron-accepting properties for applications in organic electronic devices.
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15
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Abstract
Small-molecule organic semiconductors have displayed remarkable electronic properties with a multitude of π-conjugated structures developed and fine-tuned over recent years to afford highly efficient hole- and electron-transporting materials. Already making a significant impact on organic electronic applications including organic field-effect transistors and solar cells, this class of materials is also now naturally being considered for the emerging field of organic bioelectronics. In efforts aimed at identifying and developing (semi)conducting materials for bioelectronic applications, particular attention has been placed on materials displaying mixed ionic and electronic conduction to interface efficiently with the inherently ionic biological world. Such mixed conductors are conveniently evaluated using an organic electrochemical transistor, which further presents itself as an ideal bioelectronic device for transducing biological signals into electrical signals. Here, we review recent literature relevant for the design of small-molecule mixed ionic and electronic conductors. We assess important classes of p- and n-type small-molecule semiconductors, consider structural modifications relevant for mixed conduction and for specific interactions with ionic species, and discuss the outlook of small-molecule semiconductors in the context of organic bioelectronics.
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Controlling morphology, adhesion, and electrochromic behavior of
PEDOT
films through molecular design and processing. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210522] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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17
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Effect of substituting non-polar chains with polar chains on the structural dynamics of small organic molecule and polymer semiconductors. Phys Chem Chem Phys 2021; 23:7462-7471. [PMID: 33876106 DOI: 10.1039/d1cp00670c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The processability and optoelectronic properties of organic semiconductors can be tuned and manipulated via chemical design. The substitution of the popular alkyl side chains by oligoethers has recently been successful for applications such as bioelectronic sensors and photocatalytic hydrogen evolution. Beyond the differences in polarity, the carbon-oxygen bond in oligoethers is likely to render the system softer and more prone to dynamical disorder that can be detrimental to charge transport for example. In this context, we use neutron spectroscopy as a master method of probe, in addition to characterisation techniques such as X-ray diffraction, differential scanning calorimetry and polarized optical microscopy to study the effect of the substitution of n-hexyl (Hex) chains by triethylene glycol (TEG) chains on the structural dynamics of two organic semiconducting materials: a phenylene-bithiophene-phenylene (PTTP) small molecule and a fluorene-co-dibenzothiophene (FS) polymer. Counterintuitively, inelastic neutron scattering (INS) reveals a general softening of the modes of PTTP and FS materials with Hex chains, pointing towards an increased dynamical disorder in the Hex-based systems. However, temperature-dependent X-ray and neutron diffraction as well as INS and differential scanning calorimetry evidence an extra reversible transition close to room temperature for PTTP with TEG chains. The observed extra structural transition, which is not accompanied by a change in birefringence, can also be observed by quasi-elastic neutron scattering (QENS). A fastening of the TEG chains dynamics is observed in the case of PTTP and not FS. We therefore assign this transition to the melt of the TEG chains. Overall the TEG chains are promoting dynamical order at room temperature, but if crystallising, may introduce an extra reversible structural transition above room temperature leading to thermal instabilities. Ultimately, a deeper understanding of chain polarity and structural dynamics can help guide new materials design and navigate the intricate balance between electronic charge transport and aqueous swelling that is being sought for a number of emerging organic electronic and bioelectronic applications.
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Solution-Processed Donor-Acceptor Poly(3-hexylthiophene):Phenyl-C 61-butyric Acid Methyl Ester Diodes for Low-Voltage α Particle Detection. ACS APPLIED MATERIALS & INTERFACES 2021; 13:6470-6479. [PMID: 33527828 DOI: 10.1021/acsami.0c22210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Diodes fabricated using a blend of poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester (6-80 μm thick) as an organic semiconductor component achieved consistent 4 MeV α particle detection. Current-voltage characteristics and current-time measurements were obtained under α irradiation and in its absence. Steady-state and transient (time-of-flight) photoconduction measurements were additionally performed. Low-bias (<20 V) α particle detection gain-efficiency products of order 10-2 were measured. The α particle detection was achieved reproducibly, reversibly, and repeatably in different devices of varying organic semiconductor layer thicknesses using both the steady-state and time-dependent (dynamic) diode responses. Conductive gain, due to trapped electrons, increased the α particle gain-efficiency product in both forward and reverse bias conditions as well as increasing steady-state photoconduction. The device thickness was optimized to maximize the gain-efficiency product by matching the penetration depth of the α particle, obtained by modeling, to the organic semiconductor layer thickness. Very high confidence α particle detection was achieved (with signal-to-noise ratios exceeding 20) under optimized device dimensions and drive conditions. Hecht function fitting of the gain-efficiency product versus electric field data returns mobility-lifetime products of order 10-6-10-7 cm2 V-1. This work demonstrates that solution-processed organic semiconductor diodes are viable for low-voltage α particle detection.
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The role of chemical design in the performance of organic semiconductors. Nat Rev Chem 2020; 4:66-77. [PMID: 37128048 DOI: 10.1038/s41570-019-0152-9] [Citation(s) in RCA: 210] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2019] [Indexed: 12/15/2022]
Abstract
Organic semiconductors are solution-processable, lightweight and flexible and are increasingly being used as the active layer in a wide range of new technologies. The versatility of synthetic organic chemistry enables the materials to be tuned such that they can be incorporated into biological sensors, wearable electronics, photovoltaics and flexible displays. These devices can be improved by improving their material components, not only by developing the synthetic chemistry but also by improving the analytical and computational techniques that enable us to understand the factors that govern material properties. Judicious molecular design provides control of the semiconductor frontier molecular orbital energy distribution and guides the hierarchical assembly of organic semiconductors into functional films where we can manipulate the properties and motion of charges and excited states. This Review describes how molecular design plays an integral role in developing organic semiconductors for electronic devices in present and emerging technologies.
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Glycolated Thiophene‐Tetrafluorophenylene Copolymers for Bioelectronic Applications: Synthesis by Direct Heteroarylation Polymerisation. Chempluschem 2019; 84:1384-1390. [DOI: 10.1002/cplu.201900254] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/14/2019] [Indexed: 11/08/2022]
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Performance Improvements in Conjugated Polymer Devices by Removal of Water-Induced Traps. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1801874. [PMID: 30022541 DOI: 10.1002/adma.201801874] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/07/2018] [Indexed: 06/08/2023]
Abstract
The exploration of a wide range of molecular structures has led to the development of high-performance conjugated polymer semiconductors for flexible electronic applications including displays, sensors, and logic circuits. Nevertheless, many conjugated polymer field-effect transistors (OFETs) exhibit nonideal device characteristics and device instabilities rendering them unfit for industrial applications. These often do not originate in the material's intrinsic molecular structure, but rather in external trap states caused by chemical impurities or environmental species such as water. Here, a highly efficient mechanism is demonstrated for the removal of water-induced traps that are omnipresent in conjugated polymer devices even when processed in inert environments; the underlying mechanism is shown, by which small-molecular additives with water-binding nitrile groups or alternatively water-solvent azeotropes are capable of removing water-induced traps leading to a significant improvement in OFET performance. It is also shown how certain polymer structures containing strong hydrogen accepting groups will suffer from poor performances due to their high susceptibility to interact with water molecules; this allows the design guidelines for a next generation of stable, high-performing conjugated polymers to be set forth.
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Tuning the effective spin-orbit coupling in molecular semiconductors. Nat Commun 2017; 8:15200. [PMID: 28492241 PMCID: PMC5437270 DOI: 10.1038/ncomms15200] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/09/2017] [Indexed: 02/05/2023] Open
Abstract
The control of spins and spin to charge conversion in organics requires understanding the molecular spin-orbit coupling (SOC), and a means to tune its strength. However, quantifying SOC strengths indirectly through spin relaxation effects has proven difficult due to competing relaxation mechanisms. Here we present a systematic study of the g-tensor shift in molecular semiconductors and link it directly to the SOC strength in a series of high-mobility molecular semiconductors with strong potential for future devices. The results demonstrate a rich variability of the molecular g-shifts with the effective SOC, depending on subtle aspects of molecular composition and structure. We correlate the above g-shifts to spin-lattice relaxation times over four orders of magnitude, from 200 to 0.15 μs, for isolated molecules in solution and relate our findings for isolated molecules in solution to the spin relaxation mechanisms that are likely to be relevant in solid state systems.
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Synthesis of Hetero-bifunctional, End-Capped Oligo-EDOT Derivatives. Chem 2017; 2:125-138. [PMID: 28149959 PMCID: PMC5268340 DOI: 10.1016/j.chempr.2016.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/09/2016] [Accepted: 12/09/2016] [Indexed: 11/17/2022]
Abstract
Conjugated oligomers of 3,4-ethylenedioxythiophene (EDOT) are attractive materials for tissue engineering applications and as model systems for studying the properties of the widely used polymer poly(3,4-ethylenedioxythiophene). We report here the facile synthesis of a series of keto-acid end-capped oligo-EDOT derivatives (n = 2-7) through a combination of a glyoxylation end-capping strategy and iterative direct arylation chain extension. Importantly, these structures not only represent the longest oligo-EDOTs reported but are also bench stable, in contrast to previous reports on such oligomers. The constructs reported here can undergo subsequent derivatization for integration into higher-order architectures, such as those required for tissue engineering applications. The synthesis of hetero-bifunctional constructs, as well as those containing mixed-monomer units, is also reported, allowing further complexity to be installed in a controlled manner. Finally, we describe the optical and electrochemical properties of these oligomers and demonstrate the importance of the keto-acid in determining their characteristics.
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Abstract
Commensurate epitaxial monolayers of truxenone on Cu (111) were employed to template the growth of monolayer and bilayer C60. Through the combination of STM imaging and LEED analysis we have demonstrated that C60 forms a commensurate 8 × 8 overlayer on truxenone/Cu (111). Bilayers of C60 retain the 8 × 8 periodicity of templated monolayers and although Kagome lattice arrangements are observed these are explained with combinations of 8 × 8 symmetry.
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Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors. J Am Chem Soc 2016; 138:10252-9. [PMID: 27444189 PMCID: PMC4991841 DOI: 10.1021/jacs.6b05280] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The organic electrochemical transistor (OECT), capable of transducing small ionic fluxes into electronic signals in an aqueous environment, is an ideal device to utilize in bioelectronic applications. Currently, most OECTs are fabricated with commercially available conducting poly(3,4-ethylenedioxythiophene) (PEDOT)-based suspensions and are therefore operated in depletion mode. Here, we present a series of semiconducting polymers designed to elucidate important structure-property guidelines required for accumulation mode OECT operation. We discuss key aspects relating to OECT performance such as ion and hole transport, electrochromic properties, operational voltage, and stability. The demonstration of our molecular design strategy is the fabrication of accumulation mode OECTs that clearly outperform state-of-the-art PEDOT-based devices, and show stability under aqueous operation without the need for formulation additives and cross-linkers.
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New Insights into the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction: A Time-of-Flight Quasi-Elastic Neutron Scattering Study. J Phys Chem Lett 2016; 7:2252-2257. [PMID: 27192930 DOI: 10.1021/acs.jpclett.6b00537] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The molecular dynamics of organic semiconductor blend layers are likely to affect the optoelectronic properties and the performance of devices such as solar cells. We study the dynamics (5-50 ps) of the poly(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) blend by time-of-flight quasi-elastic neutron scattering, at temperatures in the range 250-360 K, thus spanning the glass transition temperature region of the polymer and the operation temperature of an OPV device. The behavior of the QENS signal provides evidence for the vitrification of P3HT upon blending, especially above the glass transition temperature, and the plasticization of PCBM by P3HT, both dynamics occurring on the picosecond time scale.
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High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor. Nat Commun 2016; 7:11585. [PMID: 27279376 PMCID: PMC4906164 DOI: 10.1038/ncomms11585] [Citation(s) in RCA: 385] [Impact Index Per Article: 48.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 04/12/2016] [Indexed: 12/24/2022] Open
Abstract
Solution-processed organic photovoltaics (OPV) offer the attractive prospect of low-cost, light-weight and environmentally benign solar energy production. The highest efficiency OPV at present use low-bandgap donor polymers, many of which suffer from problems with stability and synthetic scalability. They also rely on fullerene-based acceptors, which themselves have issues with cost, stability and limited spectral absorption. Here we present a new non-fullerene acceptor that has been specifically designed to give improved performance alongside the wide bandgap donor poly(3-hexylthiophene), a polymer with significantly better prospects for commercial OPV due to its relative scalability and stability. Thanks to the well-matched optoelectronic and morphological properties of these materials, efficiencies of 6.4% are achieved which is the highest reported for fullerene-free P3HT devices. In addition, dramatically improved air stability is demonstrated relative to other high-efficiency OPV, showing the excellent potential of this new material combination for future technological applications.
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Abstract
PURPOSE In this paper, we aimed to collect genetic and medical information on all Danish patients with Peutz-Jeghers syndrome (PJS), in order to contribute to the knowledge of phenotype and genotype. Peutz-Jeghers syndrome is a hereditary syndrome characterized by multiple hamartomatous polyps in the GI tract, mucocutaneous pigmentations, and an increased risk of cancer in the GI tract and at extraintestinal sites. Over 90 % of patients harbour a pathogenic mutation in STK11. METHODS Based on the Danish Pathology Data Bank, the Danish National Patient Register, as well as information from relevant departments at Danish hospitals, we identified patients and collected clinical and genetic information. RESULTS We identified 43 patients of which 14 were deceased. The prevalence was estimated to be ∼1 in 195,000 individuals. The median age at first symptom was 27.5 with invagination of the small bowel as the most frequent presenting symptom. We noted 18 occurrences of cancer at various anatomical sites, including a case of thyroid cancer and penile cancer. Eight of the deceased patients had died of cancer. Eighteen different mutations in STK11 had been detected in 28 patients. CONCLUSION This is the first comprehensive study of patients with Peutz-Jeghers syndrome in the Danish population identified from nationwide registers and databases. We have demonstrated that the expressivity of Peutz-Jeghers syndrome varies greatly among the patients, even within the same families, underlining the great phenotypic spectrum. Patients with PJS should be offered surveillance from childhood in order to prevent morbidity and reduce mortality.
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Organic Photovoltaics: More than Ever, an Interdisciplinary Field. Polymers (Basel) 2016; 8:E70. [PMID: 30979164 PMCID: PMC6432563 DOI: 10.3390/polym8030070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 02/29/2016] [Indexed: 01/04/2023] Open
Abstract
Despite the growing interest and rapid advancement of alternative photovoltaic (PV) technologies such as perovskite based PV devices, we still believe that organic photovoltaic (OPV) devices have a significant potential for stable, low-cost solar power generation. [...].
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Abstract
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The active
layer in a solution processed organic photovoltaic device
comprises a light absorbing electron donor semiconductor, typically
a polymer, and an electron accepting fullerene acceptor. Although
there has been huge effort targeted to optimize the absorbing, energetic,
and transport properties of the donor material, fullerenes remain
as the exclusive electron acceptor in all high performance devices.
Very recently, some new non-fullerene acceptors have been demonstrated
to outperform fullerenes in comparative devices. This Account describes
this progress, discussing molecular design considerations and the
structure–property relationships that are emerging. The
motivation to replace fullerene acceptors stems from their
synthetic inflexibility, leading to constraints in manipulating frontier
energy levels, as well as poor absorption in the solar spectrum range,
and an inherent tendency to undergo postfabrication crystallization,
resulting in device instability. New acceptors have to address these
limitations, providing tunable absorption with high extinction coefficients,
thus contributing to device photocurrent. The ability to vary and
optimize the lowest unoccupied molecular orbital (LUMO) energy level
for a specific donor polymer is also an important requirement, ensuring
minimal energy loss on electron transfer and as high an internal voltage
as possible. Initially perylene diimide acceptors were evaluated as
promising acceptor materials. These electron deficient aromatic molecules
can exhibit good electron transport, facilitated by close packed herringbone
crystal motifs, and their energy levels can be synthetically tuned.
The principal drawback of this class of materials, their tendency
to crystallize on too large a length scale for an optimal heterojunction
nanostructure, has been shown to be overcome through introduction
of conformation twisting through steric effects. This has been primarily
achieved by coupling two units together, forming dimers with a large
intramolecular twist, which suppresses both nucleation and crystal
growth. The generic design concept of rotationally symmetrical aromatic
small molecules with extended π orbital delocalization, including
polyaromatic hydrocarbons, phthalocyanines, etc., has also provided
some excellent small molecule acceptors. In most cases, additional
electron withdrawing functionality, such as imide or ester groups,
can be incorporated to stabilize the LUMO and improve properties.
New calamitic acceptors have been developed, where molecular orbital
hybridization of electron rich and poor segments can be judiciously
employed to precisely control energy levels. Conformation and intermolecular
associations can be controlled by peripheral functionalization leading
to optimization of crystallization length scales. In particular, the
use of rhodanine end groups, coupled electronically through short
bridged aromatic chains, has been a successful strategy, with promising
device efficiencies attributed to high lying LUMO energy levels and
subsequently large open circuit voltages.
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A thieno[3,2-b][1]benzothiophene isoindigo building block for additive- and annealing-free high-performance polymer solar cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:4702-4707. [PMID: 26175063 DOI: 10.1002/adma.201501841] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 05/16/2015] [Indexed: 06/04/2023]
Abstract
A novel photoactive polymer with two different molecular weights is reported, based on a new building block: thieno[3,2-b][1]benzothiophene isoindigo. Due to the improved crystallinity, optimal blend morphology, and higher charge mobility, solar-cell devices of the high-molecular-weight polymer exhibit a superior performance, affording efficiencies of 9.1% without the need for additives, annealing, or additional extraction layers during device fabrication.
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Abstract
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The 4,7-dithieno-2,1,3-benzothiadiazole
(DTBT) moiety and its fluorinated
counterpart are important π-conjugated building blocks in the
field of organic electronics. Here we present a combined experimental
and theoretical investigation into fundamental properties relating
to these two molecular entities and discuss the potential impact on
extended π-conjugated materials and their electronic properties.
While the fluorinated derivative, in the solid state, packs with a
cofacial overlap smaller than that of DTBT, we report experimental
evidence of stronger optical absorption as well as stronger intra-
and intermolecular contacts upon fluorination.
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2,1,3-Benzothiadiazole-5,6-dicarboxylic imide--a versatile building block for additive- and annealing-free processing of organic solar cells with efficiencies exceeding 8%. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:948-53. [PMID: 25511684 PMCID: PMC4365755 DOI: 10.1002/adma.201404858] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 10/31/2014] [Indexed: 06/01/2023]
Abstract
A new photoactive polymer comprising benzo[1,2-b:3,4-b':5,6-d']trithiophene and 2,1,3-benzothiadiazole-5,6-dicarboxylic imide is reported. The synthetic design allows for alkyl chains to be introduced on both electron-rich and electron-deficient components, which in turn allows for rapid optimization of the alkyl chain substitution pattern. Consequently, the optimized polymer shows a maximum efficiency of 8.3% in organic photovoltaic devices processed in a commercially viable fashion without solvent additives, annealing, or device engineering.
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Chalcogenophene comonomer comparison in small band gap diketopyrrolopyrrole-based conjugated polymers for high-performing field-effect transistors and organic solar cells. J Am Chem Soc 2015; 137:1314-21. [PMID: 25547347 DOI: 10.1021/ja511984q] [Citation(s) in RCA: 217] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The design, synthesis, and characterization of a series of diketopyrrolopyrrole-based copolymers with different chalcogenophene comonomers (thiophene, selenophene, and tellurophene) for use in field-effect transistors and organic photovoltaic devices are reported. The effect of the heteroatom substitution on the optical, electrochemical, and photovoltaic properties and charge carrier mobilities of these polymers is discussed. The results indicate that by increasing the size of the chalcogen atom (S < Se < Te), polymer band gaps are narrowed mainly due to LUMO energy level stabilization. In addition, the larger heteroatomic size also increases intermolecular heteroatom-heteroatom interactions facilitating the formation of polymer aggregates leading to enhanced field-effect mobilities of 1.6 cm(2)/(V s). Bulk heterojunction solar cells based on the chalcogenophene polymer series blended with fullerene derivatives show good photovoltaic properties, with power conversion efficiencies ranging from 7.1-8.8%. A high photoresponse in the near-infrared (NIR) region with excellent photocurrents above 20 mA cm(-2) was achieved for all polymers, making these highly efficient low band gap polymers promising candidates for use in tandem solar cells.
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A Rhodanine Flanked Nonfullerene Acceptor for Solution-Processed Organic Photovoltaics. J Am Chem Soc 2015; 137:898-904. [DOI: 10.1021/ja5110602] [Citation(s) in RCA: 413] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Synthesis and properties are reported for a series of unsymmetrical antiaromatic azatrioxa[8]circulenes.
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A randomized pilot study on single-port versus conventional laparoscopic rectal surgery: effects on postoperative pain and the stress response to surgery. Tech Coloproctol 2014; 19:11-22. [PMID: 25380743 DOI: 10.1007/s10151-014-1237-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/06/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND Potential benefits of single-port laparoscopic surgery may include improved cosmetic results, less postoperative pain, surgical trauma and faster recovery. Results of randomized prospective studies with a focus on single-port rectal surgery have not yet been presented. The aim of the present study was to compare single-port and conventional laparoscopic surgery for rectal cancer in terms of short-term outcomes including postoperative pain and trauma-induced changes in certain bioactive substances. METHODS Patients with non-metastasized rectal cancer were prospectively randomized to single-port (n = 20) or conventional laparoscopic rectal surgery (n = 20). Postoperative pain was assessed at rest, at coughing and during mobilization, with a numeric pain ranking score and was recorded at 6 h after the operation and subsequently every morning daily for 4 days. Levels of C-reactive protein (CRP), interleukin-6 (IL-6) and tissue inhibitor of metalloproteinases-1 (TIMP-1) were determined. Blood samples were collected preoperatively (baseline), and 6, 24, 48, 72 and 96 h after skin incision. RESULTS Pain scores were significantly reduced in the single-port group on postoperative days 2, 3 and 4 during coughing and mobilization. In addition, the patients in the single-port group suffered significantly less pain at rest at 6 h after surgery and on postoperative days 1, 3 and 4. The levels of the three markers increased significantly after surgery. The increase was similar between groups for plasma IL-6 and TIMP-1 at all time points, while the CRP levels were significantly lower in the single-port group at 6 (p < 0.001) and 24 h (p < 0.05) after skin incision. Abdominal incisions lengths were significantly shorter in the single-port group (p = 0.001). There was no significant difference between groups in operating time and blood loss, morbidity or mortality rate. The short-term oncological outcome in the two groups was similar. CONCLUSIONS Single-port rectal surgery may reduce postoperative pain. Although CRP levels were lower at some time points, results of the present randomized, pilot study suggest that the trauma-induced inflammatory response of single-port operations may be similar to the trauma-induced inflammatory response of conventional laparoscopic surgery.
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Benzotrithiophene Copolymers: Influence of Molecular Packing and Energy Levels on Charge Carrier Mobility. Macromolecules 2014. [DOI: 10.1021/ma500163u] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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The Dalton quantum chemistry program system. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2013; 4:269-284. [PMID: 25309629 PMCID: PMC4171759 DOI: 10.1002/wcms.1172] [Citation(s) in RCA: 836] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, Møller-Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients and Hessians are available for geometry optimizations, molecular dynamics, and vibrational studies, whereas magnetic resonance and optical activity can be studied in a gauge-origin-invariant manner. Frequency-dependent molecular properties can be calculated using linear, quadratic, and cubic response theory. A large number of singlet and triplet perturbation operators are available for the study of one-, two-, and three-photon processes. Environmental effects may be included using various dielectric-medium and quantum-mechanics/molecular-mechanics models. Large molecules may be studied using linear-scaling and massively parallel algorithms. Dalton is distributed at no cost from http://www.daltonprogram.org for a number of UNIX platforms.
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Alkyl side-chain branching point effects in thieno[3,4-c]pyrrole-4,6-dione copolymers. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/21606099.2013.829393] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Recent advances in the development of semiconducting DPP-containing polymers for transistor applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013. [PMID: 23008141 DOI: 10.1002/adma.v25.13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This progress report summarizes the numerous DPP-containing polymers recently developed for field-effect transistor applications including diphenyl-DPP and dithienyl-DPP-based polymers as the most commonly reported materials, but also difuranyl-DPP, diselenophenyl-DPP and dithienothienyl-DPP-containing polymers. We discuss the hole and electron mobilities that were reported in relation to structural properties such as alkyl substitution patterns, polymer molecular weights and solid state packing, as well as electronic properties including HOMO and LUMO energy levels. We moreover consider important aspects of ambipolar charge transport and highlight fundamental structure-property relations such as the relationships between the thin film morphologies and the charge carrier mobilities observed for DPP-containing polymers.
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Recent advances in the development of semiconducting DPP-containing polymers for transistor applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:1859-80. [PMID: 23008141 DOI: 10.1002/adma.201201795] [Citation(s) in RCA: 456] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/07/2012] [Indexed: 05/22/2023]
Abstract
This progress report summarizes the numerous DPP-containing polymers recently developed for field-effect transistor applications including diphenyl-DPP and dithienyl-DPP-based polymers as the most commonly reported materials, but also difuranyl-DPP, diselenophenyl-DPP and dithienothienyl-DPP-containing polymers. We discuss the hole and electron mobilities that were reported in relation to structural properties such as alkyl substitution patterns, polymer molecular weights and solid state packing, as well as electronic properties including HOMO and LUMO energy levels. We moreover consider important aspects of ambipolar charge transport and highlight fundamental structure-property relations such as the relationships between the thin film morphologies and the charge carrier mobilities observed for DPP-containing polymers.
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Note: A variable temperature cell for spectroscopy of thin films. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:046106. [PMID: 23635240 DOI: 10.1063/1.4802949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report the design and construction of a cell that enables precisely controlled measurement of UV∕Vis spectra of thin films on transparent substrates at temperatures up to 800 K. The dimensions of the setup are accommodated by a standard Varian Cary 5E spectrophotometer allowing for widespread use in standard laboratory settings. The cell also fits in a Bio-Rad IR-spectrometer. The cell is constructed with an outer water cooled heat shield of aluminum and an inner sample holder with heating element, thermo-resistor and windows, made from nickel coated copper. The cell can operate both in air, and with an inert gas filling. We illustrate the utility of the cell by characterization of three commercially available near infrared absorbers that are commonly used for laser welding of plastics and are known to possess high thermal stability.
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Improved field-effect transistor performance of a benzotrithiophene polymer through ketal cleavage in the solid state. ACS APPLIED MATERIALS & INTERFACES 2013; 5:1806-1810. [PMID: 23379256 DOI: 10.1021/am303138q] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A benzotrithiophene polymer with a new thermally cleavable ketal substituent is reported. It is shown how this functional group can be used to facilitate solvent processing and, subsequently, how it can be removed by a thermal annealing process to generate a structurally ordered and crystalline thin film with significantly improved field-effect transistor properties.
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Azatrioxa[8]circulenes: Planar Anti-Aromatic Cyclooctatetraenes. Chemistry 2013; 19:3898-904. [DOI: 10.1002/chem.201203113] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Indexed: 11/07/2022]
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Fused Dithienogermolodithiophene Low Band Gap Polymers for High-Performance Organic Solar Cells without Processing Additives. J Am Chem Soc 2013; 135:2040-3. [DOI: 10.1021/ja311700u] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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