- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Mobility Evaluation of BTBT Derivatives: Limitation and Impact on Charge Transport
摘要： Amongst contemporary semiconductors many of the best performing materials are based on [1]benzothieno[3,2-b][1]benzothiophene (BTBT). Alkylated derivatives of these small molecules not only provide high hole mobilities but can also be easily processed by thermal vacuum or solution deposition methods. Over the last decade numerous publications have been investigating molecular structures and charge transport properties to elucidate what makes these molecules so special. However, the race towards ever higher mobilities resulted in significantly deviating values, which exacerbates linking molecular structure to electronic properties. Moreover, a recently arisen debate on overestimation of organic field-effect transistor mobilities calls for a revaluation of these numbers. We synthesised and characterised four BTBT derivatives with either one or two alkyl chains (themselves consisting of either eight or ten carbon atoms), and investigated their spectroscopic, structural and electrical properties. By employing two probes, gated 4-point probe and gated van der Pauw measurements, we compare field effect mobility values at room and low temperatures, and discuss their feasibility and viability. We attribute mobility changes to different angles between molecule planes and core-to-core double layer stacking of asymmetric BTBT derivatives and show higher mobilities in the presence of more and longer alkyl chains. A so called “zipper effect” brings BTBT cores in closer proximity promoting stronger intermolecular orbital coupling and hence higher charge transport.
关键词： charge transport,mobility,BTBT,organic electronics,organic transistors
更新于2025-10-23 16:08:52
-
Preferred orientation of 2,7-dioctyl[1]benzothieno[3,2- <i>b</i> ][1]benzothiophene molecules on inorganic single-crystal substrates with various orientations
摘要： The organic molecule 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) was deposited on quartz glass, e11 (cid:2)20T A-, (0001) C-, and e1 (cid:2)102T R-single-crystal Al2O3 (sapphire), and (100)-, and (111)-single-crystal MgO substrates by vacuum thermal evaporation, and structural characterizations were carried out by X-ray di?raction analysis and atomic force microscopy (AFM) observation. The (001) out-of-plane orientation with a similar in-plane orientation was obtained irrespective of the substrate material and orientation, and its formation was governed by π–π-stacking-induced molecular ordering. The degree of orientation was re?ected by the grain structure related to the substrate material. The growth model of the oriented C8-BTBT layer was speculated on the basis of experimental results.
关键词： π–π-stacking,vacuum thermal evaporation,X-ray diffraction,C8-BTBT,atomic force microscopy
更新于2025-09-23 15:21:21
-
Vapor-deposited all inorganic CsPbBr3 thin films and interface modification with C8-BTBT for high performance photodetector
摘要： All inorganic perovskites like CsPbBr3 have attracted rising attention and are considered as promising candidates for optoelectronic devices. Here we fabricated CsPbBr3 films by co-evaporation. The as-deposited and low temperature (below 300 °C) annealed films are in a mixture phase of CsPbBr3 and CsPb2Br5. After 400 °C annealing in ambient air, the CsPbBr3 phase becomes dominant with a good crystal structure and less defects. Then, 2,7-diocty[1]benzothieno-[3,2-b]benzothiophen (C8-BTBT) was deposited on the CsPbBr3 film layer-by-layer to investigate the interface electronic structure with X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). As C8-BTBT was deposited, p-doping effect was observed at the surface of CsPbBr3 by the interface energy level alignment. At the same time, we also observed a chemical reaction at the interface and a small amount of lead sulfite might be formed. CsPbBr3 based photodetectors with or without C8-BTBT modified layer were also fabricated and studied. It was found that the photocurrent of the detectors with an additional C8-BTBT layer was about two orders of magnitude higher than that without C8-BTBT layer. The responsivities and response time are also improved with C8-BTBT. We attribute the improvement of photoelectronic properties to the interface energy level adjustment by the C8-BTBT. These results highlight the potential of C8-BTBT as a modified layer for inorganic perovskite optoelectronic devices.
关键词： CsPbBr3 films,C8-BTBT,Interfacial electronic structures,Vacuum evaporation,Photoelectronic properties
更新于2025-09-23 15:21:01
-
[IEEE 2018 Second International Conference on Computing Methodologies and Communication (ICCMC) - Erode (2018.2.15-2018.2.16)] 2018 Second International Conference on Computing Methodologies and Communication (ICCMC) - Optimization of N+ hetero pocket doped Dual metal Vertical TFET
摘要： In this paper, an N+ hetero pocket doped Dual metal Vertical TFET is proposed. Due to an additional tunneling contribution to current along the body thickness of the device the proposed device offers larger ON current and steeper subthreshold slope (SS) as compare to conventional Tunnel FET. Here, the n+ pocket doping is incorporated near the gate source overlap region. Moreover, the pocket material is optimized with different bandgap materials. The dual metal gate (DMG) is used and compared with single material gate (SMG). Further, with an n+ layer at the p-source side, improvements in the device performance in terms of on-current (10-3A), subthreshold swing, SS (39mV/dec) are achieved. The proposed device is optimized for channel length, silicon body layer thickness, source doping engineering, gate dielectric material. Finally, the analog performance of the device is examined and found the device is suitable for high frequency application.
关键词： Dual Material Gate (DMG),Vertical TFET,Single Material Gate(SMG),Band-to-band tunneling (BTBT)
更新于2025-09-23 15:21:01
-
Simultaneously improving the photovoltaic parameters of organic solar cells <i>via</i> isomerization of benzo[ <i>b</i> ]benzo[4,5]thieno[2,3- <i>d</i> ]thiophene-based octacyclic non-fullerene acceptors
摘要： Fused-ring electron acceptors (FREAs) have attracted immense interest owing to their ability for facile structural modification and good thermal and optical characteristics. Among these acceptors, isomerized building blocks originate from multiple reaction sites affect the electronic structures, morphological properties and resulting photovoltaic performance, but have rarely been studied. Herein, three isomeric FREAs, Z1-aa, Z1-ab, and Z1-bb, were synthesized using different reaction sites of benzo[b]benzo[4,5]thieno[2,3-d]thiophene (BTBT)-based fused-ring cores and were used in organic solar cells (OSCs). As compared to Z1-aa and Z1-ab, Z1-bb exhibited red-shifted absorption and a higher maximum molar extinction coefficient. When blended with PM6, Z1-bb-based OSCs exhibited more balanced charge transport compared to those with the PM6:Z1-aa and PM6:Z1-ab blend films, which favored higher short-circuit current density (Jsc) and fill factor (FF). As a result, the OSC devices based on Z1-bb exhibited a power conversion efficiency (PCE) of 12.66% with Voc = 0.98 V, Jsc = 18.52 mA cm-2, and FF = 70.05%, respectively, which are significantly higher than the values recorded for Z1-ab-based (PCE of 9.60%)?and Z1-aa-based (PCE of 4.56%) devices. These results indicate that the isomerization of a fused-ring core originating from a special reaction site could be a promising approach to achieve high-performance OSCs with high Jsc, Voc, and FF.
关键词： Organic solar cells,Isomerization,Fused-ring electron acceptors,BTBT-based fused-ring cores,Photovoltaic performance
更新于2025-09-23 15:19:57
-
Inverted Perovskite Solar Cells Based on Small Molecular Hole Transport Material C <sub/>8</sub> ‐BTBT
摘要： The small organic molecular Dioctylbenzothienobenzothiophene (C8-BTBT) has been explored as hole transport material (HTM) to replace PEDOT:PSS in inverted perovskite solar cells (PVSCs). MAPbI3 perovskite films depositd onto C8-BTBT are smooth and uniform, with negligible residual of PbI2 and large grain size even larger than 1 μm. Our champion C8-BTBT based devices reached a high power conversion efficiency (PCE) of 15.46% with marginal hysteresis, much higher than that of 11.50% achieved using PEDOT:PSS. Besides, device adopting C8-BTBT as substrate show superior stability compared with the PEDOT:PSS based devices when stored under ambient conditions with a relative humidity of 25±5%.
关键词： perovskite solar cells,stability,PEDOT:PSS,hole transport material,C8-BTBT
更新于2025-09-19 17:13:59
-
Solution-processed organic field-effect transistors using directed assembled carbon nanotubes and 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT)
摘要： Achieving low-cost fabrication of organic field-effect transistors (OFETs) has long been pursued in the semiconductor industry. Solution-based process allows the fabrication of OFETs cost-effective because of its merit of vacuum-free and room temperature operation. Here, we show a facile and scalable fabrication of solution-processed OFETs using carbon nanotube (CNT) as source/drain electrodes and 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) as semiconducting layer on silicon as well as on flexible and transparent polyethylene terephthalate (PET) substrates. The CNT electrodes and the C8-BTBT film are fabricated using a dip coating-based directed assembly process, and two dip coating parameters, the pulling speed and the solution concentration, are carefully chosen so that the thickness of the C8-BTBT film is close to that of the CNT electrodes. The fabricated OFET devices show typical p-channel behavior. Low-cost, ease of processing, wafer level scalability and good compatibility with various substrates make the fabrication process presented in this paper well suited for next-generation electronics and sensors.
关键词： carbon nanotube,C8-BTBT,directed assembly,transistor
更新于2025-09-19 17:13:59
-
A new medium-bandgap fused-[1]benzothieno[3,2-b][1]benzo-thiophene (BTBT) nonfullerene acceptor for organic solar cells with high open-circuit voltage
摘要： A new nonfullerene small molecule acceptor, namely DBTIC, based on a octocyclic thieno[3,2-b]thienodi(indenothiophene) unit using [1]benzothieno[3,2-b][1]-benzothiophene as the core unit, was developed. Despite the medium-bandgap of DBTIC (1.71 eV), a power conversion efficiency of 8.64% can be delivered by the solar cells combining DBTIC and a wide-bandgap polymer donor J52. The high open-circuit voltage (Voc) of 0.94 V is also rare for J52 based devices owing to the high-lying lowest unoccupied molecular orbital level of DBTIC. Moreover, using J71 with lower highest occupied molecular orbital level as polymer donor, a higher Voc up to 1.05 V can be achieved.
关键词： high open-circuit voltage,nonfullerene acceptor,organic solar cells,BTBT,medium-bandgap
更新于2025-09-12 10:27:22
-
[IEEE 2018 Conference on Emerging Devices and Smart Systems (ICEDSS) - Tiruchengode, India (2018.3.2-2018.3.3)] 2018 Conference on Emerging Devices and Smart Systems (ICEDSS) - A Comparison of Analytical Modeling of Double Gate and Dual material Double GateTFETs with high-KStacked Gate-Oxide Structure forLow power Applications
摘要： In this paper, an analytical comparative study of Double Gate Tunnel Field Effect Transistors(DG-TFETs) and Dual Material Double Gate Tunnel Field Effect Transistors(DMDG-TFETs) with high-K stacked gate oxide structure are presented. The modeling is done by solving the Poisson’s equation with Parabolic Approximation Technique with suitable boundary conditions. By using channel potential model, Surface potential is calculated.The Drain current model is developed by integrating band to band tunneling generation rate. The different electrical characteristics like surface potential, Electric field and Drain current have been compared for both TFETs in this paper. On comparing DG-TFETs with Dual material, DMDG-TFETs provide an enhanced performance. The analytical results are also compared with TCAD simulated results for both the devices and good agreement is observed.
关键词： Band-to-band tunneling (BTBT),Tunnel FET (TFET),Dual-material (DM) gate,Parabolic Approximation Technique
更新于2025-09-09 09:28:46
-
Alloy Engineered Nitride Tunneling Field-Effect Transistor: A Solution for the Challenge of Heterojunction TFETs
摘要： Being fundamentally limited to a current–voltage steepness of 60 mV/dec, MOSFETs struggle to operate below 0.6 V. Further reduction in VDD and, consequently, power consumption can be achieved with novel devices, such as tunneling transistors (TFETs) that can overcome this limitation. TFETs, however, face challenges with low ON-current leading to slow performance. TFETs made from III-nitride heterostructures are quite promising in this regard. The lattice mismatch induces a piezoelectric polarization field in a nitride heterojunction that can boost the ON-current. However, it is shown here that the carrier thermalization at the heterointerface degrades the subthreshold characteristics. Therefore, a good design should minimize the number of confined quantum well (QW) states at the heterointerface so as not to degrade the subthreshold characteristics while maintaining the lattice mismatch induced polarization to boost the ON-current. We show here that an InAlN QW on an InGaN substrate alloy engineered TFET design is promising to fulfill these requirements. Proper engineering of the alloy mole fractions and the width of the well can eliminate (or at least minimize) the undesired thermalization effects and, at the same time, provide a lattice mismatch to induce a piezoelectric field for boosting the ON-current. We have used a suitable atomistic quantum transport model to simulate these devices. The model accounts for the different mechanisms that are involved, and captures realistic scattering thermalization effects. This model has been benchmarked in our earlier work with experimental measurements of nitride tunneling heterojunction diodes and is used here to optimize the alloy engineered nitride TFET.
关键词： EQNEQ,band-to-band tunneling (BTBT),phenomenological scattering,nitrides,TFET,tight binding (TB),Atomistic,nonequilibrium Green’s function (NEGF),internal polarization,steep devices
更新于2025-09-09 09:28:46