| 1. |
- Can, Ayse, et al.
(författare)
-
Indenofluorenes for organic optoelectronics: the dance of fused five- and six-membered rings enabling structural versatility
- 2022
-
Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 10:22, s. 8496-8535
-
Forskningsöversikt (refereegranskat)abstract
- Polycyclic pi-conjugated hydrocarbons (PCHs), either unfunctionalized or structurally modified derivatives, have attracted tremendous interest in the past few decades as high-performance semiconductors for use in new generations of organic (opto)electronic devices. Among several PCHs realized to date, the 6-5-6-5-6 pi-fused-ring backbone of indenofluorene (IF) stands out as a unique semiconducting architecture with great structural and property versatility affording six different regioisomers, diverse functionalization/substitution positions, pi-conjugation/delocalization patterns, aromatic behaviors, and electronic structures. In this review, we summarize and analyze the historical and recent advances in the design and implementation of IF-based semiconductors in organic transistor and solar cell devices, as well as in understanding the chemical structure-molecular property-semiconductivity relationships. Following an introduction to the fascinating properties of an IF pi-framework that distinguishes this core among PCHs, we present IF-based semiconductors and discuss their properties by classifying them into four main families (IF-diones, IF-DCVs/IF-TTFs, pi-IFs, and (un)substituted DH-IFs) considering whether methylene or methine C-bridges are present and how these positions are functionalized or substituted. For each family, design and synthetic approaches, molecular properties, and transistor/solar cell device applicability and/or performance are reviewed and discussed. At the end, we conclude with a section discussing the challenges and opportunities for future progress of IF-based semiconductor materials and related (opto)electronic technologies.
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| 2. |
- Chen, Jianhua, et al.
(författare)
-
Highly stretchable organic electrochemical transistors with strain-resistant performance
- 2022
-
Ingår i: Nature Materials. - : NATURE PORTFOLIO. - 1476-1122 .- 1476-4660. ; 21, s. 564-571
-
Tidskriftsartikel (refereegranskat)abstract
- Realizing fully stretchable electronic materials is central to advancing new types of mechanically agile and skin-integrable optoelectronic device technologies. Here we demonstrate a materials design concept combining an organic semiconductor film with a honeycomb porous structure with biaxially prestretched platform that enables high-performance organic electrochemical transistors with a charge transport stability over 30-140% tensional strain, limited only by metal contact fatigue. The prestretched honeycomb semiconductor channel of donor-acceptor polymer poly(2,5-bis(2-octyldodecyl)-3,6-di(thiophen-2-yl)-2,5-diketo-pyrrolopyrrole-alt-2,5-bis(3-triethyleneglycoloxy-thiophen-2-yl) exhibits high ion uptake and completely stable electrochemical and mechanical properties over 1,500 redox cycles with 10(4) stretching cycles under 30% strain. Invariant electrocardiogram recording cycles and synapse responses under varying strains, along with mechanical finite element analysis, underscore that the present stretchable organic electrochemical transistor design strategy is suitable for diverse applications requiring stable signal output under deformation with low power dissipation and mechanical robustness. Highly stretchable organic electrochemical transistors with stable charge transport under severe tensional strains are demonstrated using a honeycomb semiconducting polymer morphology, thereby enabling controllable signal output for diverse stretchable bioelectronic applications.
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| 3. |
- Eckstein, Brian J., et al.
(författare)
-
Naphthalene Bis(4,8-diamino-1,5-dicarboxyl)amide Building Block for Semiconducting Polymers
- 2017
-
Ingår i: Journal of the American Chemical Society. - : AMER CHEMICAL SOC. - 0002-7863 .- 1520-5126. ; 139:41, s. 14356-14359
-
Tidskriftsartikel (refereegranskat)abstract
- We report a new naphthalene bis(4,8-diamino-1,5-dicarboxyl)amide (NBA) building block for polymeric semiconductors. Computational modeling suggests that regio-connectivity at the 2,6- or 3,7-NBA positions strongly modulates polymer backbone torsion and, therefore, intramolecular pi-conjugation and aggregation. Optical, electrochemical, and X-ray diffraction characterization of 3,7- and 2,6-dithienyl-substituted NBA molecules and, corresponding isomeric NBA, bithiophene copolymers P1 and P2, respectively, reveals the key role of regio-connectivity. Charge transport measurements demonstrate that while the twisted 3,7-NDA-based P1 is a poor semiconductor, the planar 2,6-functionalized NBA polymers (P2-P4) exhibit ambipolarity, with mu(e) and mu(h) of up to 0.39 and 0.32 cm(2)/(V.s), respectively.
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| 4. |
- Eckstein, Brian J., et al.
(författare)
-
Processable High Electron Mobility pi-Copolymers via Mesoscale Backbone Conformational Ordering
- 2021
-
Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 31:15
-
Tidskriftsartikel (refereegranskat)abstract
- The synthesis and experimental/theoretical characterization of a new series of electron-transporting copolymers based on the naphthalene bis(4,8-diamino-1,5-dicarboxyl)amide (NBA) building block are reported. Comonomers are designed to test the emergent effects of manipulating backbone torsional characteristics, and density functional theory (DFT) analysis reveals the key role of backbone conformation in optimizing electronic delocalization and transport. The NBA copolymer conformational and electronic properties are characterized using a broad array of molecular/macromolecular, thermal, optical, electrochemical, and charge transport techniques. All NBA copolymers exhibit strongly aggregated morphologies with significant nanoscale order. Copolymer charge transport properties are investigated in thin-film transistors and exhibit excellent electron mobilities ranging from 0.4 to 4.5 cm(2) V-1 s(-1). Importantly, the electron transport efficiency correlates with the film mesoscale order, which emerges from comonomer-dependent backbone planarity and extension. These results illuminate the key NBA building block structure-morphology-bulk property design relationships essential for processable, electronics-applicable high-performance polymeric semiconductors.
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| 5. |
- Erdmann, Tim, et al.
(författare)
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Naphthalenediimide Polymers with Finely Tuned In-Chain pi-Conjugation: Electronic Structure, Film Microstructure, and Charge Transport Properties
- 2016
-
Ingår i: ADVANCED MATERIALS. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 28:41, s. 9169-
-
Tidskriftsartikel (refereegranskat)abstract
- Naphthalenediimide-based random copolymers (PNDI-TVTx) with different p-conjugated dithienylvinylene (TVT) versus p-nonconjugated dithienylethane (TET) unit ratios (x = 100 -amp;gt; 0%) are investigated. The PNDI-TVTx-transistor electron/hole mobilities are affected differently, a result rationalized by molecular orbital topologies and energies, with hole mobility vanishing but electron mobility decreasing only by approximate to 2.5 times when going from x = 100% to 40%.
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| 6. |
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| 7. |
- Fabiano, Simone, et al.
(författare)
-
Stretchable helix-structured fibre electronics
- 2021
-
Ingår i: NATURE ELECTRONICS. - : NATURE PORTFOLIO. - 2520-1131. ; 4, s. 864-865
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Printed thin-film transistors and circuits fabricated on plastic strips can be wrapped around fibres to create stretchable electronics.
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| 8. |
- Guo, Han, et al.
(författare)
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Transition metal-catalysed molecular n-doping of organic semiconductors
- 2021
-
Ingår i: Nature. - London, United Kingdom : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 599:7883, s. 67-73
-
Tidskriftsartikel (refereegranskat)abstract
- Electron doping of organic semiconductors is typically inefficient, but here a precursor molecular dopant is used to deliver higher n-doping efficiency in a much shorter doping time. Chemical doping is a key process for investigating charge transport in organic semiconductors and improving certain (opto)electronic devices(1-9). N(electron)-doping is fundamentally more challenging than p(hole)-doping and typically achieves a very low doping efficiency (eta) of less than 10%(1,10). An efficient molecular n-dopant should simultaneously exhibit a high reducing power and air stability for broad applicability(1,5,6,9,11), which is very challenging. Here we show a general concept of catalysed n-doping of organic semiconductors using air-stable precursor-type molecular dopants. Incorporation of a transition metal (for example, Pt, Au, Pd) as vapour-deposited nanoparticles or solution-processable organometallic complexes (for example, Pd-2(dba)(3)) catalyses the reaction, as assessed by experimental and theoretical evidence, enabling greatly increased eta in a much shorter doping time and high electrical conductivities (above 100 S cm(-1); ref. (12)). This methodology has technological implications for realizing improved semiconductor devices and offers a broad exploration space of ternary systems comprising catalysts, molecular dopants and semiconductors, thus opening new opportunities in n-doping research and applications(12, 13).
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| 9. |
- He, Guang S., et al.
(författare)
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Twisted pi-System Chromophores for All-Optical Switching
- 2011
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 133:17, s. 6675-6680
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Tidskriftsartikel (refereegranskat)abstract
- Molecular chromophores with twisted pi-electron systems have been shown to possess unprecedented values of the quadratic hyperpolarizability, beta, with very large real parts and much smaller imaginary parts. We report here an experimental and theoretical study which shows that these twisted chromophores also possess very large values of the real part of the cubic hyperpolarizability, gamma, which is responsible for nonlinear refraction. Thus, for the two-ring twisted chromophore TMC-2 at 775 nm, relatively close to one-photon resonance, n(2) extrapolated to neat substance is large and positive (1.87 x 10(-13) cm(2)/W), leading to self-focusing. Furthermore, the third-order response includes a remarkably low two-photon absorption coefficient, which means minimal nonlinear optical losses: the T factor, alpha(2)lambda/n(2), is 0.308. These characteristics are attributed to closely spaced singlet biradical and zwitterionic states and offer promise for applications in all-optical switching.
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| 10. |
- Jin, Wenlong, et al.
(författare)
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Photocatalytic doping of organic semiconductors
- 2024
-
Ingår i: Nature. - : NATURE PORTFOLIO. - 0028-0836 .- 1476-4687.
-
Tidskriftsartikel (refereegranskat)abstract
- Chemical doping is an important approach to manipulating charge-carrier concentration and transport in organic semiconductors (OSCs) 1-3 and ultimately enhances device performance 4-7 . However, conventional doping strategies often rely on the use of highly reactive (strong) dopants 8-10 , which are consumed during the doping process. Achieving efficient doping with weak and/or widely accessible dopants under mild conditions remains a considerable challenge. Here, we report a previously undescribed concept for the photocatalytic doping of OSCs that uses air as a weak oxidant (p-dopant) and operates at room temperature. This is a general approach that can be applied to various OSCs and photocatalysts, yielding electrical conductivities that exceed 3,000 S cm-1. We also demonstrate the successful photocatalytic reduction (n-doping) and simultaneous p-doping and n-doping of OSCs in which the organic salt used to maintain charge neutrality is the only chemical consumed. Our photocatalytic doping method offers great potential for advancing OSC doping and developing next-generation organic electronic devices. A previously undescribed photocatalytic approach enables the effective p-type and n-type doping of organic semiconductors at room temperature using only widely available weak dopants such as oxygen and triethylamine.
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| 11. |
- Kim, Jaehyun, et al.
(författare)
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Monolithically integrated high-density vertical organic electrochemical transistor arrays and complementary circuits
- 2024
-
Ingår i: NATURE ELECTRONICS. - : NATURE PORTFOLIO. - 2520-1131.
-
Tidskriftsartikel (refereegranskat)abstract
- Organic electrochemical transistors (OECTs) can be used to create biosensors, wearable devices and neuromorphic systems. However, restrictions in the micro- and nanopatterning of organic semiconductors, as well as topological irregularities, often limit their use in monolithically integrated circuits. Here we show that the micropatterning of organic semiconductors by electron-beam exposure can be used to create high-density (up to around 7.2 million OECTs per cm2) and mechanically flexible vertical OECT arrays and circuits. The energetic electrons convert the semiconductor exposed area to an electronic insulator while retaining ionic conductivity and topological continuity with the redox-active unexposed areas essential for monolithic integration. The resulting p- and n-type vertical OECT active-matrix arrays exhibit transconductances of 0.08-1.7 S, transient times of less than 100 mu s and stable switching properties of more than 100,000 cycles. We also fabricate vertically stacked complementary logic circuits, including NOT, NAND and NOR gates. Micropatterning of organic semiconductors by electron-beam exposure can be used to create vertical organic electrochemical transistor arrays and complementary logic circuits with densities of up to 7.2 million transistors per cm2.
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| 12. |
- Luo, Yifei, et al.
(författare)
-
Technology Roadmap for Flexible Sensors
- 2023
-
Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
-
Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 13. |
- Moschetto, Salvatore, et al.
(författare)
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Interplay between Charge Injection, Electron Transport, and Quantum Efficiency in Ambipolar Trilayer Organic Light-Emitting Transistors
- 2022
-
Ingår i: Advanced Materials Interfaces. - : Wiley. - 2196-7350. ; 9:5
-
Tidskriftsartikel (refereegranskat)abstract
- The fascinating characteristic of organic light-emitting transistors (OLETs) of being electrical switches with an intrinsic light-emitting capability makes them attractive candidates for a wide variety of applications, ranging from sensors to displays. To date, the OLET ambipolar trilayer heterostructure is the most developed architecture for maximizing device performance. However, a major challenge of trilayer OLETs remains the inverse correlation between external quantum efficiency and brightness under ambipolar conditions. The complex interconnection between electroluminescent and ambipolar charge transport properties, in conjunction with the limited availability of electron transport semiconducting materials, has indeed hampered the disruptive evolution of the OLET technology. Here, an in-depth study of the interplay of the key fundamental features that determine the device performance is reported by exploring electron transport semiconductors with different properties in ambipolar trilayer OLETs. Through the selection of compounds with tailored chemical structures, the relation between intrinsic optoelectronic characteristics of the electron transport semiconductor, energy level alignment within the structure, and morphological features is unraveled. Furthermore, the introduction of a suitable electron injector at the emissive/semiconducting layers interface sheds light into the bidimensional nature of OLETs that is a distinguishing factor of this class of devices with respect to prototypical organic light-emitting diodes.
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| 14. |
- Stoeckel, Marc-Antoine, et al.
(författare)
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On-Demand Catalysed n-Doping of Organic Semiconductors
- 2024
-
Ingår i: Angewandte Chemie International Edition. - : WILEY-V C H VERLAG GMBH. - 1433-7851 .- 1521-3773.
-
Tidskriftsartikel (refereegranskat)abstract
- A new approach to control the n-doping reaction of organic semiconductors is reported using surface-functionalized gold nanoparticles (f-AuNPs) with alkylthiols acting as the catalyst only upon mild thermal activation. To demonstrate the versatility of this methodology, the reaction of the n-type dopant precursor N-DMBI-H with several molecular and polymeric semiconductors at different temperatures with/without f-AuNPs, vis-a-vis the unfunctionalized catalyst AuNPs, was investigated by spectroscopic, morphological, charge transport, and kinetic measurements as well as, computationally, the thermodynamic of catalyst activation. The combined experimental and theoretical data demonstrate that while f-AuNPs is inactive at room temperature both in solution and in the solid state, catalyst activation occurs rapidly at mild temperatures (similar to 70 degrees C) and the doping reaction completes in few seconds affording large electrical conductivities (similar to 10-140 S cm(-1)). The implementation of this methodology enables the use of semiconductor+dopant+catalyst solutions and will broaden the use of the corresponding n-doped films in opto-electronic devices such as thin-film transistors, electrochemical transistors, solar cells, and thermoelectrics well as guide the design of new catalysts.
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| 15. |
- Trippodo, Elisa, et al.
(författare)
-
Air-stable ternary organic solar cells achieved by using fullerene additives in non-fullerene acceptor-polymer donor blends
- 2023
-
Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 11:24, s. 8074-8083
-
Tidskriftsartikel (refereegranskat)abstract
- Organic solar cells (OSCs) based on donor-acceptor blends have shown a rapid improvement in power conversion efficiency (PCE) now approaching, for small cells, those of the state-of-the art commercial solar modules. However, performance degradation remains one of the most critical impediments for OSC technology commercialization. Ternary solar cells where a third component, for instance an acceptor, is added to a non-fullerene acceptor-polymer donor blend are an effective approach for improving both OSC efficiency and long-term stability. Here, we study the role of two fullerene acceptors, ET18 and PCBM, as the third component in P-D:Y6 blends. These fullerene derivatives significantly enhance the cell stability, which retained > 90% of their initial PCEs (13-14%) even after storage in air for 6 months, compared to only similar to 20% retention for the binary devices. GIWAXS, AFM, in situ impedance spectroscopy and femtosecond transient absorption spectroscopy measurements reveal that the enhanced stability of the ternary devices results from a more robust blend morphology reducing charge recombination in the ternary devices during aging.
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| 16. |
- Wang, Gang, et al.
(författare)
-
Aggregation control in natural brush-printed conjugated polymer films and implications for enhancing charge transport
- 2017
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 114:47, s. E10066-E10073
-
Tidskriftsartikel (refereegranskat)abstract
- Shear-printing is a promising processing technique in organic electronics for microstructure/charge transport modification and large-area film fabrication. Nevertheless, the mechanism by which shear-printing can enhance charge transport is not well-understood. In this study, a printing method using natural brushes is adopted as an informative tool to realize direct aggregation control of conjugated polymers and to investigate the interplay between printing parameters, macromolecule backbone alignment and aggregation, and charge transport anisotropy in a conjugated polymer series differing in architecture and electronic structure. This series includes (i) semicrystalline hole-transporting P3HT, (ii) semicrystalline electron transporting N2200, (iii) low-crystallinity hole-transporting PBDTT-FTTE, and (iv) low-crystallinity conducting PEDOT:PSS. The (semi-)conducting films are characterized by a battery of morphology and microstructure analysis techniques and by charge transport measurements. We report that remarkably enhanced mobilities/conductivities, as high as 5.7x/3.9x, are achieved by controlled growth of nanofibril aggregates and by backbone alignment, with the adjusted R-2 (R-adj(2)) correlation between aggregation and charge transport as high as 95%. However, while shear-induced aggregation is important for enhancing charge transport, backbone alignment alone does not guarantee charge transport anisotropy. The correlations between efficient charge transport and aggregation are clearly shown, while mobility and degree of orientation are not always well-correlated. These observations provide insights into macroscopic charge transport mechanisms in conjugated polymers and suggest guidelines for optimization.
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| 17. |
- Wang, Gang, et al.
(författare)
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Mixed-flow design for microfluidic printing of two-component polymer semiconductor systems
- 2020
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 117:30, s. 17551-17557
-
Tidskriftsartikel (refereegranskat)abstract
- The rational creation of two-component conjugated polymer sys-tems with high levels of phase purity in each component is challenging but crucial for realizing printed soft-matter electronics. Here, we report a mixed-flow microfluidic printing (MFMP) approach for two-component pi-polymer systems that significantly elevates phase purity in bulk-heterojunction solar cells and thin-film transistors. MFMP integrates laminar and extensional flows using a specially microstructured shear blade, designed with fluid flow simulation tools to tune the flow patterns and induce shear, stretch, and pushout effects. This optimizes polymer conformation and semi-conducting blend order as assessed by atomic force microscopy (AFM), transmission electron microscopy (TEM), grazing incidence wide-angle X-ray scattering (GIWAXS), resonant soft X-ray scattering (R-SoXS), photovoltaic response, and field effect mobility. For printed all-polymer (poly[(5,6-difluoro-2-octyl-2H-benzotriazole-4,7-diyl)-2,5-thiophenediyl[4,8-bis[5-(2-hexyldecyl)-2-thienyl]benzo[1,2-b:4,5-b ]dithiophene-2,6-diyl]-2,5-thiophenediyl]) [J51]:(poly{[N,N -bis(2-octyldodecyl) naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5 -(2,2 -bithio-phene)}) [N2200]) solar cells, this approach enhances short-circuit currents and fill factors, with power conversion efficiency increasing from 5.20% for conventional blade coating to 7.80% for MFMP. Moreover, the performance of mixed polymer ambipolar [poly(3-hexylthiophene-2,5-diyl) (P3HT):N2200] and semiconducting:insulat-ing polymer unipolar (N2200:polystyrene) transistors is similarly enhanced, underscoring versatility for two-component pi-polymer systems. Mixed-flow designs offer modalities for achieving high-performance organic optoelectronics via innovative printing methodologies.
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| 18. |
- Wang, Gang, et al.
(författare)
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Photovoltaic Blend Microstructure for High Efficiency Post-Fullerene Solar Cells. To Tilt or Not To Tilt?
- 2019
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 141:34, s. 13410-13420
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Tidskriftsartikel (refereegranskat)abstract
- Achieving efficient polymer solar cells (PSCs) requires a structurally optimal donor-acceptor heterojunction morphology. Here we report the combined experimental and theoretical characterization of a benzodithiophene-benzo-thiadiazole donor polymer series (PBTZF4-R; R = alkyl substituent) blended with the non-fullerene acceptor ITIC-Th and analyze the effects of substituent dimensions on blend morphology, charge transport, carrier dynamics, and PSC metrics. Varying substituent dimensions has a pronounced effect on the blend morphology with a direct link between domain purity, to some extent domain dimensions, and charge generation and collection. The polymer with the smallest alkyl substituent yields the highest PSC power conversion efficiency (PCE, 11%), reflecting relatively small, high-purity domains and possibly benefiting from "matched" donor polymer-small molecule acceptor orientations. The distinctive morphologies arising from the substituents are investigated using molecular dynamics (MD) simulations which reveal that substituent dimensions dictate a well-defined set of polymer conformations, in turn driving chain aggregation and, ultimately, the various film morphologies and mixing with acceptor small molecules. A straightforward energetic parameter explains the experimental polymer domain morphological trends, hence PCE, and suggests strategies for substituent selection to optimize PSC materials morphologies.
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| 19. |
- Wang, Suhao, et al.
(författare)
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A Chemically Doped Naphthalenediimide-Bithiazole Polymer for n-Type Organic Thermoelectrics
- 2018
-
Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 30:31
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of a novel naphthalenediimide (NDI)-bithiazole (Tz2)-based polymer [P(NDI2OD-Tz2)] is reported, and structural, thin-film morphological, as well as charge transport and thermoelectric properties are compared to the parent and widely investigated NDI-bithiophene (T2) polymer [P(NDI2OD-T2)]. Since the steric repulsions in Tz2 are far lower than in T2, P(NDI2OD-Tz2) exhibits a more planar and rigid backbone, enhancing p-p chain stacking and intermolecular interactions. In addition, the electron-deficient nature of Tz2 enhances the polymer electron affinity, thus reducing the polymer donor-acceptor character. When n-doped with amines, P(NDI2OD-Tz2) achieves electrical conductivity (approximate to 0.1 S cm(-1)) and a power factor (1.5 mu W m(-1) K-2) far greater than those of P(NDI2OD-T2) (0.003 S cm(-1) and 0.012 mu W m(-1) K-2, respectively). These results demonstrate that planarized NDI-based polymers with reduced donor-acceptor character can achieve substantial electrical conductivity and thermoelectric response.
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| 20. |
- Wang, Suhao, et al.
(författare)
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Effect of Backbone Regiochemistry on Conductivity, Charge Density, and Polaron Structure of n-Doped Donor-Acceptor Polymers
- 2019
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 31:9, s. 3395-3406
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the influence of backbone regiochemistry on the conductivity, charge density, and polaron structure in the widely studied n-doped donor-acceptor polymer poly[N,N-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl]-alt-5,5-(2,2-bithiophene) [P-(NDI2OD-T2)]. In contrast to classic semicrystalline polymers such as poly(3-hexylthiophene) (P3HT), the regioirregular (RI) structure of the naphthalenediimide (NDI)-bithiophene (T2) backbone does not alter the intramolecular steric demand of the chain versus the regioregular (RR) polymer, yielding RI-P(NDI2OD-T2) with similar energetics and optical features as its RR counterpart. By combining the electrical, UV-vis/infrared, X-ray diffraction, and electron paramagnetic resonance data and density functional theory calculations, we quantitatively characterized the conductivity, aggregation, crystallinity, and charge density, and simulated the polaron structures, molecular vibrations, and spin density distribution of RR-/RI-P(NDI2OD-T2). Importantly, we observed that RI-P(NDI2OD-T2) can be doped to a greater extent compared to its RR counterpart. This finding is remarkable and contrasts benchmark P3HT, allowing us to uniquely study the role of regiochemistry on the charge-transport properties of n-doped donor-acceptor polymers.
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| 21. |
- Yao, Yao, et al.
(författare)
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Flexible and Stretchable Organic Electrochemical Transistors for Physiological Sensing Devices
- 2023
-
Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 35:35
-
Forskningsöversikt (refereegranskat)abstract
- Flexible and stretchable bioelectronics provides a biocompatible interface between electronics and biological systems and has received tremendous attention for in situ monitoring of various biological systems. Considerable progress in organic electronics has made organic semiconductors, as well as other organic electronic materials, ideal candidates for developing wearable, implantable, and biocompatible electronic circuits due to their potential mechanical compliance and biocompatibility. Organic electrochemical transistors (OECTs), as an emerging class of organic electronic building blocks, exhibit significant advantages in biological sensing due to the ionic nature at the basis of the switching behavior, low driving voltage (<1 V), and high transconductance (in millisiemens range). During the past few years, significant progress in constructing flexible/stretchable OECTs (FSOECTs) for both biochemical and bioelectrical sensors has been reported. In this regard, to summarize major research accomplishments in this emerging field, this review first discusses structure and critical features of FSOECTs, including working principles, materials, and architectural engineering. Next, a wide spectrum of relevant physiological sensing applications, where FSOECTs are the key components, are summarized. Last, major challenges and opportunities for further advancing FSOECT physiological sensors are discussed.
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| 22. |
- Zhao, Dan, et al.
(författare)
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Mechanical, Morphological, and Charge Transport Properties of NDI Polymers with Variable Built-in Π-Conjugation Lengths Probed by Simulation and Experiment
- 2024
-
Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-3028 .- 1616-301X. ; 34:4
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Tidskriftsartikel (refereegranskat)abstract
- Mechanically deformable polymeric semiconductors are a key material for fabricating flexible organic thin-film transistors (FOTFTs)-the building block of electronic circuits and wearable electronic devices. However, for many pi-conjugated polymers achieving mechanical deformability and efficient charge transport remains challenging. Here the effects of polymer backbone bending stiffness and film microstructure on mechanical flexibility and charge transport are investigated via experimental and computational methods for a series of electron-transporting naphthalene diimide (NDI) polymers having differing extents of pi-conjugation. The results show that replacing increasing amounts of the pi-conjugated comonomer dithienylvinylene (TVT) with the pi-nonconjugated comonomer dithienylethane (TET) in the backbone of the fully pi-conjugated polymeric semiconductor, PNDI-TVT100 (yielding polymeric series PNDI-TVTx, 100 >= x >= 0), lowers backbone rigidity, degree of texturing, and pi-pi stacking interactions between NDI moieties. Importantly, this comonomer substitution increases the mechanical robustness of PNDI-TVTx while retaining efficient charge transport. Thus, reducing the TVT content of PNDI-TVTx suppresses film crack formation and dramatically stabilizes the field-effect electron mobility upon bending (e.g., 2 mm over 2000 bending cycles). This work provides a route to tune pi-pi stacking in pi-conjugated polymers while simultaneously promoting mechanical flexibility and retaining good carrier mobility in FOTFTs.
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