396 results found
Basu A, Niazi MR, Scaccabarozzi AD, et al., 2020, Impact of p-type doping on charge transport in blade-coated small-molecule:polymer blend transistors, Journal of Materials Chemistry C, Vol: 8, Pages: 15368-15376, ISSN: 2050-7534
© The Royal Society of Chemistry. Blade-coating is a roll-to-roll (R2R) compatible processing technique and has the potential to address the industry's needs for scalable manufacturing of future organic electronics. Here we investigate the applicability of blade-coating for the fabrication of organic thin-film transistors (OTFTs) based on best-in-class organic semiconducting blends comprised of the conjugated small-molecule 2,7-dioctylbenzothieno[3,2-b]benzothiophene (C8-BTBT), and the conjugated polymer poly(indacenodithiophene-co-benzothiadiazole) (C16IDT-BT). We show that the operating characteristics of blade-coated transistors consistently outperform devices prepared via spin-coating, showcasing the compatibility of the technique. Introducing the molecular p-dopant C60F48 into the binary C8-BTBT:C16IDT-BT blend formulation, in combination with carefully optimized blade-coating conditions, helps to enhance the performance of the ensuing transistors further resulting in a maximum hole mobility of ≈14 cm2 V-1 s-1, and an all-around improvement of the device operating characteristics. Our results show that p-doped blend OTFTs can be manufactured using industry relevant processing techniques without sacrificing their state-of-the-art performance. This journal is
Liu J, van der Zee B, Alessandri R, et al., 2020, N-type organic thermoelectrics: demonstration of ZT > 0.3., Nat Commun, Vol: 11
The 'phonon-glass electron-crystal' concept has triggered most of the progress that has been achieved in inorganic thermoelectrics in the past two decades. Organic thermoelectric materials, unlike their inorganic counterparts, exhibit molecular diversity, flexible mechanical properties and easy fabrication, and are mostly 'phonon glasses'. However, the thermoelectric performances of these organic materials are largely limited by low molecular order and they are therefore far from being 'electron crystals'. Here, we report a molecularly n-doped fullerene derivative with meticulous design of the side chain that approaches an organic 'PGEC' thermoelectric material. This thermoelectric material exhibits an excellent electrical conductivity of >10 S cm-1 and an ultralow thermal conductivity of <0.1 Wm-1K-1, leading to the best figure of merit ZT = 0.34 (at 120 °C) among all reported single-host n-type organic thermoelectric materials. The key factor to achieving the record performance is to use 'arm-shaped' double-triethylene-glycol-type side chains, which not only offer excellent doping efficiency (~60%) but also induce a disorder-to-order transition upon thermal annealing. This study illustrates the vast potential of organic semiconductors as thermoelectric materials.
Bristow H, Jacoutot P, Scaccabarozzi AD, et al., 2020, Nonfullerene-Based Organic Photodetectors for Ultrahigh Sensitivity Visible Light Detection., ACS Appl Mater Interfaces, Vol: 12, Pages: 48836-48844
It is well established that for organic photodetectors (OPDs) to compete with their inorganic counterparts, low dark currents at reverse bias must be achieved. Here, two rhodanine-terminated nonfullerene acceptors O-FBR and O-IDTBR are shown to deliver low dark currents at -2 V of 0.17 and 0.84 nA cm-2, respectively, when combined with the synthetically scalable polymer PTQ10 in OPD. These low dark currents contribute to the excellent sensitivity to low light of the detectors, reaching values of 0.57 μW cm-2 for PTQ10:O-FBR-based OPD and 2.12 μW cm-2 for PTQ10:O-IDTBR-based OPD. In both cases, this sensitivity exceeds that of a commercially available silicon photodiode. The responsivity of the PTQ10:O-FBR-based OPD of 0.34 AW-1 under a reverse bias of -2 V also exceeds that of a silicon photodiode. Meanwhile, the responsivity of the PTQ10:O-IDTBR of 0.03 AW-1 is limited by the energetic offset of the blend. The OPDs deliver high specific detectivities of 9.6 × 1012 Jones and 3.3 × 1011 Jones for O-FBR- and O-IDTBR-based blends, respectively. Both active layers are blade-coated in air, making them suitable for high-throughput methods. Finally, all three of the materials can be synthesized at low cost and on a large scale, making these blends good candidates for commercial OPD applications.
Portilla L, Zhao J, Wang Y, et al., 2020, Ambipolar Deep-Subthreshold Printed-Carbon-Nanotube Transistors for Ultralow-Voltage and Ultralow-Power Electronics., ACS Nano, Vol: 14, Pages: 14036-14046
The development of ultralow-power and easy-to-fabricate electronics with potential for large-scale circuit integration (i.e., complementary or complementary-like) is an outstanding challenge for emerging off-the-grid applications, e.g., remote sensing, "place-and-forget", and the Internet of Things. Herein we address this challenge through the development of ambipolar transistors relying on solution-processed polymer-sorted semiconducting carbon nanotube networks (sc-SWCNTNs) operating in the deep-subthreshold regime. Application of self-assembled monolayers at the active channel interface enables the fine-tuning of sc-SWCNTN transistors toward well-balanced ambipolar deep-subthreshold characteristics. The significance of these features is assessed by exploring the applicability of such transistors to complementary-like integrated circuits, with respect to which the impact of the subthreshold slope and flatband voltage on voltage and power requirements is studied experimentally and theoretically. As demonstrated with inverter and NAND gates, the ambipolar deep-subthreshold sc-SWCNTN approach enables digital circuits with complementary-like operation and characteristics including wide noise margins and ultralow operational voltages (≤0.5 V), while exhibiting record-low power consumption (≤1 pW/μm). Among thin-film transistor technologies with minimal material complexity, our approach achieves the lowest energy and power dissipation figures reported to date, which are compatible with and highly attractive for emerging off-the-grid applications.
Karuthedath S, Gorenflot J, Firdaus Y, et al., 2020, Intrinsic efficiency limits in low-bandgap non-fullerene acceptor organic solar cells., Nat Mater, ISSN: 1476-1122
In bulk heterojunction (BHJ) organic solar cells (OSCs) both the electron affinity (EA) and ionization energy (IE) offsets at the donor-acceptor interface should equally control exciton dissociation. Here, we demonstrate that in low-bandgap non-fullerene acceptor (NFA) BHJs ultrafast donor-to-acceptor energy transfer precedes hole transfer from the acceptor to the donor and thus renders the EA offset virtually unimportant. Moreover, sizeable bulk IE offsets of about 0.5 eV are needed for efficient charge transfer and high internal quantum efficiencies, since energy level bending at the donor-NFA interface caused by the acceptors' quadrupole moments prevents efficient exciton-to-charge-transfer state conversion at low IE offsets. The same bending, however, is the origin of the barrier-less charge transfer state to free charge conversion. Our results provide a comprehensive picture of the photophysics of NFA-based blends, and show that sizeable bulk IE offsets are essential to design efficient BHJ OSCs based on low-bandgap NFAs.
Firdaus Y, Le Corre VM, Karuthedath S, et al., 2020, Long-range exciton diffusion in molecular non-fullerene acceptors., Nat Commun, Vol: 11
The short exciton diffusion length associated with most classical organic semiconductors used in organic photovoltaics (5-20 nm) imposes severe limits on the maximum size of the donor and acceptor domains within the photoactive layer of the cell. Identifying materials that are able to transport excitons over longer distances can help advancing our understanding and lead to solar cells with higher efficiency. Here, we measure the exciton diffusion length in a wide range of nonfullerene acceptor molecules using two different experimental techniques based on photocurrent and ultrafast spectroscopy measurements. The acceptors exhibit balanced ambipolar charge transport and surprisingly long exciton diffusion lengths in the range of 20 to 47 nm. With the aid of quantum-chemical calculations, we are able to rationalize the exciton dynamics and draw basic chemical design rules, particularly on the importance of the end-group substituent on the crystal packing of nonfullerene acceptors.
Isakov I, Faber H, Mottram AD, et al., 2020, Quantum Confinement and Thickness-Dependent Electron Transport in Solution-Processed In(2)O(3)Transistors, ADVANCED ELECTRONIC MATERIALS, ISSN: 2199-160X
Li W, Yarali E, Bakytbekov A, et al., 2020, Highly transparent and conductive electrodes enabled by scalable printing-and-sintering of silver nanowires, NANOTECHNOLOGY, Vol: 31, ISSN: 0957-4484
Xue F, He X, Liu W, et al., 2020, Optoelectronic Ferroelectric Domain-Wall Memories Made from a Single Van Der Waals Ferroelectric, ADVANCED FUNCTIONAL MATERIALS, ISSN: 1616-301X
Lin Y, Firdaus Y, Isikgor FH, et al., 2020, Self-Assembled Monolayer Enables Hole Transport Layer-Free Organic Solar Cells with 18% Efficiency and Improved Operational Stability, ACS ENERGY LETTERS, Vol: 5, Pages: 2935-2944, ISSN: 2380-8195
Scaccabarozzi AD, Scuratti F, Barker AJ, et al., 2020, Understanding charge transport in high-mobilityp-doped multicomponent blend organic transistors, Advanced Electronic Materials, Pages: 1-9, ISSN: 2199-160X
The use of ternary systems comprising polymers, small molecules, and molecular dopants represents a promising approach for the development of high‐mobility, solution‐processed organic transistors. However, the current understanding of the charge transport in these complex systems, and particularly the role of molecular doping, is rather limited. Here, the role of the individual components in enhancing hole transport in the best‐performing ternary blend systems comprising the small molecule 2,7‐dioctylbenzothieno[3,2‐b]benzothiophene (C8‐BTBT), the conjugated polymer indacenodithiophene‐alt‐benzothiadiazole (C16IDT‐BT), and the molecular p‐type dopant (C60F48) is investigated. Temperature‐dependent charge transport measurements reveal different charge transport regimes depending on the blend composition, crossing from a thermally activated to a band‐like behavior. Using the charge‐modulation spectroscopy technique, it is shown that in the case of the pristine blend, holes relax onto the conjugated polymer phase where shallow traps dominate carrier transport. Addition of a small amount of C60F48 deactivates those shallow traps allowing for a higher degree of hole delocalization within the highly crystalline C8‐BTBT domains located on the upper surface of the blend film. Such synergistic effect of a highly ordered C8‐BTBT phase, a polymer bridging grain boundaries, and p‐doping results in the exceptionally high hole mobilities and band‐like transport observed in this blend system.
Aljarb A, Fu J-H, Hsu C-C, et al., 2020, Ledge-directed epitaxy of continuously self-aligned single-crystalline nanoribbons of transition metal dichalcogenides, NATURE MATERIALS, ISSN: 1476-1122
Seitkhan A, Neophytou M, Hallani RK, et al., 2020, A Multilayered Electron Extracting System for Efficient Perovskite Solar Cells, ADVANCED FUNCTIONAL MATERIALS, ISSN: 1616-301X
Chang X, Fang J, Fan Y, et al., 2020, Printable CsPbI(3)Perovskite Solar Cells with PCE of 19% via an Additive Strategy, ADVANCED MATERIALS, ISSN: 0935-9648
Mohan L, Ratnasingham SR, Panidi J, et al., 2020, Low Temperature Scalable Deposition of Copper(I) Thiocyanate Films via Aerosol-Assisted Chemical Vapor Deposition, Crystal Growth & Design, Vol: 20, Pages: 5380-5386, ISSN: 1528-7483
Copper(I) thiocyanate (CuSCN) is a stable, wide bandgap (>3.5 eV), low-cost p-type semiconductor widely used in a variety of optoelectronic applications, including thin film transistors, organic light-emitting diodes, and photovoltaic cells. For CuSCN to have impact in the commercial fabrication of such devices, large-area, low-cost deposition techniques are required. Here, we report a novel technique for deposition of CuSCN that addresses these challenges. Aerosol-assisted chemical vapor deposition (AACVD) is used to deposit highly crystalline CuSCN films at low temperature. AACVD is a commercially viable technique due to its low cost and inherent scalability. In this study, the deposition temperature, CuSCN concentration and carrier gas flow rate were studied and optimized, resulting in homogeneous films grown over areas approaching 30 cm2. At the optimized values, i.e., 60 °C using a 35 mg/mL solution and a carrier gas flow rate of 0.5 dm3/min, the film growth rate is around 100 nm/min. We present a thorough analysis of the film growth parameters and the subsequent morphology, composition, and structural and optical properties of the deposited thin films.
Zhang S, Tang M-C, Fan Y, et al., 2020, Role of Alkali-Metal Cations in Electronic Structure and Halide Segregation of Hybrid Perovskites, ACS APPLIED MATERIALS & INTERFACES, Vol: 12, Pages: 34402-34412, ISSN: 1944-8244
Anies F, Wang S, Hodsden T, et al., 2020, A Structurally Simple but High-Performing Donor-Acceptor Polymer for Field-Effect Transistor Applications, ADVANCED ELECTRONIC MATERIALS, Vol: 6, ISSN: 2199-160X
Nugraha M, Yarali E, Firdaus Y, et al., 2020, Rapid Photonic Processing of High-Electron-Mobility PbS Colloidal Quantum Dot Transistors, ACS APPLIED MATERIALS & INTERFACES, Vol: 12, Pages: 31591-31600, ISSN: 1944-8244
Cheng F, Verrelli E, Alharthi FA, et al., 2020, Solution-processable and photopolymerisable TiO(2)nanorods as dielectric layers for thin film transistors, RSC ADVANCES, Vol: 10, Pages: 25540-25546
Tang M-C, Fan Y, Barrit D, et al., 2020, Efficient Hybrid Mixed-Ion Perovskite Photovoltaics: In Situ Diagnostics of the Roles of Cesium and Potassium Alkali Cation Addition, SOLAR RRL, Vol: 4, ISSN: 2367-198X
Yang X, Lin Y, Liu J, et al., 2020, A Highly Conductive Titanium Oxynitride Electron-Selective Contact for Efficient Photovoltaic Devices, ADVANCED MATERIALS, Vol: 32, ISSN: 0935-9648
Kirmani AR, Eisner F, Mansour AE, et al., 2020, Colloidal Quantum Dot Photovoltaics Using Ultrathin, Solution-Processed Bilayer In2O3/ZnO Electron Transport Layers with Improved Stability, ACS APPLIED ENERGY MATERIALS, Vol: 3, Pages: 5135-5141, ISSN: 2574-0962
Paterson AF, Savva A, Wustoni S, et al., 2020, Water stable molecular n-doping produces organic electrochemical transistors with high transconductance and record stability, NATURE COMMUNICATIONS, Vol: 11, ISSN: 2041-1723
Lin Y-H, Huang W, Pattanasattayavong P, et al., 2020, Deciphering photocarrier dynamics for tuneable high-performance perovskite-organic semiconductor heterojunction phototransistors (vol 10, 4475, 2019), NATURE COMMUNICATIONS, Vol: 11, ISSN: 2041-1723
Dauzon E, Lin Y, Faber H, et al., 2020, Stretchable and Transparent Conductive PEDOT:PSS-Based Electrodes for Organic Photovoltaics and Strain Sensors Applications, ADVANCED FUNCTIONAL MATERIALS, Vol: 30, ISSN: 1616-301X
Khan JI, Firdaus Y, Cruciani F, et al., 2020, Thienyl Sidechain Substitution and Backbone Fluorination of Benzodithiophene-Based Donor Polymers Concertedly Minimize Carrier Losses in ITIC-Based Organic Solar Cells, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 124, Pages: 10420-10429, ISSN: 1932-7447
Ho CHY, Kim T, Xiong Y, et al., 2020, High-Performance Tandem Organic Solar Cells Using HSolar as the Interconnecting Layer, ADVANCED ENERGY MATERIALS, Vol: 10, ISSN: 1614-6832
Yarali E, Faber H, Yengel E, et al., 2020, Low-Voltage Heterojunction Metal Oxide Transistors via Rapid Photonic Processing, ADVANCED ELECTRONIC MATERIALS, Vol: 6, ISSN: 2199-160X
Anthopoulos TD, Noh Y-Y, Jurchescu OD, 2020, Emerging Thin-Film Transistor Technologies and Applications, ADVANCED FUNCTIONAL MATERIALS, Vol: 30, ISSN: 1616-301X
Ma C, Clark S, Liu Z, et al., 2020, Solution-Processed Mixed-Dimensional Hybrid Perovskite/Carbon Nanotube Electronics, ACS NANO, Vol: 14, Pages: 3969-3979, ISSN: 1936-0851
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