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1.
    
Detecting and understanding ambipolar charge accumulation and transport are essential for constructing ambipolar organic field-effect transistors (OFETs). However, it is difficult to determine carrier motion using general electrical tests. Here, the generalized gated four-probe (G-GFP) technique is extended to ambipolar transistors made of diketopyrrolopyrrole-thieno[3,2-b]thiophene copolymer (DPPT-TT), and the motion of the internal carrier during operation is investigated. The evolution of the local potential is monitored in the channel to establish a clear and quantitative picture of accumulation and transport for two types of carriers during device operation. Both simulation and experimental results verify that G-GFP is a suitable and accessible approach for extracting the device mobility of ambipolar transistors. An ambipolar device with a G-GFP structure can function as a single-OFET inverter, demonstrating that G-GFP can serve as an effective tool for ambipolar transistor analysis, while simultaneously facilitating the implementation of logic functions.  相似文献   

2.
    
Digital logic accommodating more than two data levels is at the forefront of future high‐information‐density electronics. The fundamental mechanisms of the organic ternary inverters relying on anti‐ambipolarity are revealed. Ideally combining the analytical and predictive capabilities of simulation, the three distinctive regimes of operation are identified, and systematic guidelines for how to balance the “0,” “1/2,” and “1” voltage levels are suggested. Most importantly, the junction energy barrier and minority carrier penetration are found to be critical to this type of inverter. In time with the increasing viability of flexible multi‐valued logic circuits, such theoretical insights are positioned to spearhead the next engineering efforts on optimized performances.  相似文献   

3.
    
Alkyl chains are basic units in the design of organic semiconductors for purposes of enhancing solubility, tuning electronic energy levels, and tailoring molecular packing. This work demonstrates that the carrier mobilities of indeno[1,2‐b ]fluorene‐6,12‐dione ( IFD )‐based semiconductors can be dramatically enhanced by the incorporation of sulfur‐ or nitrogen‐linked side chains. Three IFD derivatives possessing butyl, butylthio, and dibutylamino substituents are synthesized, and their organic field‐effect transistors (OFET) are fabricated and characterized. The IFD possessing butyl substituents exhibits a very poor charge transport property with mobility lower than 10?7 cm2 V?1 s?1. In contrast, the hole mobility is dramatically increased to 1.03 cm2 V?1 s?1 by replacing the butyl units with dibutylamino groups ( DBA‐IFD ), while the butylthio‐modified IFD ( BT‐IFD ) derivative exhibits a high and balanced ambipolar charge transport property with the maximum hole and electron mobilities up to 0.71 and 0.65 cm2 V?1 s?1, respectively. Moreover, the complementary metal–oxide–semiconductor‐like inverters incorporated with the ambipolar OFETs shows sharp inversions with a maximum gain value up to 173. This work reveals that modification of the aromatic core with heteroatom‐linked side chains, such as alkylthio or dialkylamino, can be an efficient strategy for the design of high‐performance organic semiconductors.  相似文献   

4.
    
Ambipolar charge transport in a solution‐processed small molecule 4,7‐bis{2‐[2,5‐bis(2‐ethylhexyl)‐3‐(5‐hexyl‐2,2′:5′,2″‐terthiophene‐5″‐yl)‐pyrrolo[3,4‐c]pyrrolo‐1,4‐dione‐6‐yl]‐thiophene‐5‐yl}‐2,1,3‐benzothiadiazole (BTDPP2) transistor has been investigated and shows a balanced field‐effect mobility of electrons and holes of up to ～10?2 cm2 V?1 s?1. Using low‐work‐function top electrodes such as Ba, the electron injection barrier is largely reduced. The observed ambipolar transport can be enhanced over one order of magnitude compared to devices using Al or Au electrodes. The field‐effect mobility increases upon thermal annealing at 150 °C due to the formation of large crystalline domains, as shown by atomic force microscopy and X‐ray diffraction. Organic inverter circuits based on BTDPP2 ambipolar transistors display a gain of over 25.  相似文献   

5.
    
A ternary inverter is demonstrated based on an organic antiambipolar transistor (AAT), in which the output logic states can be precisely controlled with appropriate optical signals. First, the photoresponse of AATs consisting of PTCDI-C8 and α-6T layers is systematically investigated. Under visible light, the Λ-shaped transfer curve of the AATs undergoes a noticeable broadening due to the optically induced threshold voltage shift in both the PTCDI-C8 and α-6T controlled ranges. Under ultraviolet light, broadening is observed only on the α-6T side. These contrasting impacts of the two light signals enable to tune the balance of the ternary logic states in the inverters, including the output voltage levels and the ratio of the respective logic states. Such optically controlled ternary logic circuits possess great potential for their application in next-generation optoelectronic devices.  相似文献   

6.
    
Split‐gate ambipolar organic transistor technology is gaining interests as a practical solution for the implementation of complementary transistors. It is known that conventional ambipolar transistors suffer from poor DC gain, noise margin, and high power consumption, as they do not have a well‐defined off‐state region. A split‐gate device structure enables ambipolar transistors operating in a controlled unipolar mode (both p‐type and n‐type), resulting in superior inverter characteristics. A key challenge in previously reported split‐gate ambipolar organic thin‐film transistors is the strong current–voltage instabilities due to charge trapping at the dielectric interface. Here, the first split‐gate ambipolar organic transistors with top‐gate/bottom‐contact structure are demonstrated. Compared to the previous split‐gate devices, the top‐split‐gate ambipolar organic transistor exhibits superior electrical properties. The proposed device shows hysteresis‐free I–V characteristics as well as higher bias stress stability. Furthermore, the complementary inverter circuit using the proposed transistors is also demonstrated, which results in a higher output swing and DC gain compared to the baseline ambipolar inverter.  相似文献   

7.
    
Delocalized singlet biradical hydrocarbons hold promise as new semiconducting materials for high‐performance organic devices. However, to date biradical organic molecules have attracted little attention as a material for organic electronic devices. Here, this work shows that films of a crystallized diphenyl derivative of s‐indacenodiphenalene (Ph2‐IDPL) exhibit high ambipolar mobilities in organic field‐effect transistors (OFETs). Furthermore, OFETs fabricated using Ph2‐IDPL single crystals show high hole mobility (μh = 7.2 × 10?1 cm2 V?1 s?1) comparable to that of amorphous Si. Additionally, high on/off ratios are achieved for Ph2‐IDPL by inserting self‐assembled mono­layer of alkanethiol between the semiconducting layer and the Au electrodes. These findings open a door to the application of ambipolar OFETs to organic electronics such as complementary metal oxide semiconductor logic circuits.  相似文献   

8.
    
Four glycolated polythiophene-based organic mixed ionic-electronic conductors (OMIECs), PE2gTT, PE2gT, PT2gTT, and PT2gT are prepared by atom-efficient direct arylation polymerization, avoiding the need for toxic organometallic precursors. PE2gT, PT2gTT, and PT2gT are operable in p-type accumulation mode organic electrochemical transistors (OECTs), with PT2gT displaying the best device performance with a µC* product figure-of-merit of 290 F cm−1 V−1 s−1. A record volumetric capacitance among p-type glycolated polythiophene OMIECs of 313 F cm−3 is observed for PE2gT , ascribed to the high proportionality of polar components in its materials design. The good OECT performance of PE2gT with µC* = 84.2 F cm−1 V−1 s−1, comparable with state-of-the-art poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) devices, coupled with its synthetic accessibility and favorable accumulation mode operation makes PE2gT an ideal glycolated alternative to PEDOT:PSS in bioelectronics. PE2gT with the least negative threshold voltage also displays the best OECT operational cycling stability, linked to better resistance of its oxidized state against parasitic redox side reactions . Shelf life stability of OECTs stored (without bias) is observed to be better for materials with a more negative threshold voltage and higher average molecular weight ( PT2gT ), that are less susceptible to ambient auto-oxidation and film delamination.  相似文献   

9.
    
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10.
    
One of the grand challenges in organic electronics is to develop multicomponent materials wherein each component imparts a different and independently addressable property to the hybrid system. In this way, the combination of the pristine properties of each component is not only preserved but also combined with unprecedented properties emerging from the mutual interaction between the components. Here for the first time, that tri‐component materials comprised of an ambipolar diketopyrrolopyrrole‐based semiconducting polymer combined with two different photochromic diarylethene molecules possessing ad hoc energy levels can be used to develop organic field‐effect transistors, in which the transport of both, holes and electrons, can be photo‐modulated. A fully reversible light‐switching process is demonstrated, with a light‐controlled 100‐fold modulation of p‐type charge transport and a tenfold modulation of n‐type charge transport. These findings pave the way for photo‐tunable inverters and ultimately for completely re‐addressable high‐performance circuits comprising optical storage units and ambipolar field‐effect transistors.  相似文献   

11.
    
Solution‐processed small‐molecule bulk heterojunction (BHJ) ambipolar organic thin‐film transistors are fabricated based on a combination of [2‐phenylbenzo[d,d']thieno[3,2‐b;4,5‐b']dithiophene (P‐BTDT) : 2‐(4‐n‐octylphenyl)benzo[d,d ']thieno[3,2‐b;4,5‐b']dithiophene (OP‐BTDT)] and C60. Treating high electrical performance vacuum‐deposited P‐BTDT organic semiconductors with a newly developed solution‐processed organic semiconductor material, OP‐BTDT, in an optimized ratio yields a solution‐processed p‐channel organic semiconductor blend with carrier mobility as high as 0.65 cm2 V?1 s?1. An optimized blending of P‐BTDT:OP‐BTDT with the n‐channel semiconductor, C60, results in a BHJ ambipolar transistor with balanced carrier mobilities for holes and electrons of 0.03 and 0.02 cm2 V?1 s?1, respectively. Furthermore, a complementary‐like inverter composed of two ambipolar thin‐film transistors is demonstrated, which achieves a gain of 115.  相似文献   

12.
    
Organic electrochemical transistors (OECTs) based complementary inverters have been considered as promising candidates in electrophysiological amplification, owing to their low power consumption, and high gain. To create complementary inverters, it is important to use highly stable p-type and n-type polymers with well-balanced current. In this study, the electrochemical stability of p-type ladder-conjugated polymer-based OECT is improved through an annealing process that maintains its doped-state drain current from 76% to 105% after 4,500 cycles in ambient environment. Next an OECT-based complementary inverter made from p-type and n-type ladder-conjugated polymers (PBBTL and BBL) that possess ultra-low power consumption (≈170 nW), high gain (67 V/V), and high noise margin (92%) with full rail-to-rail swing, is presented. Furthermore, its potential for amplifying the envelope of surface electromyography (EMG) for robotic hand control is demonstrated. The high variation in the output (0.35 V) allows the amplified EMG signals to be directly captured by a commercial analog-to-digital converter, which in turn controls the robot hand to grasp different objects with low delay and low noise. These results demonstrate the capability of OECT inverter-based amplifier in future signal processing-free human-machine interface, particularly useful for prosthetic control and gesture control applications.  相似文献   

13.
    
To date, high-performance organic electrochemical transistors (OECTs) are almost all based on conjugated polymers. Small molecules can be synthesized with high purity without batch-to-batch variations. However, small molecules require highly crystalline films and good molecular packings to achieve high charge carrier mobilities. Such features make their films unsuitable for ion diffusion or make their molecular packing distorted due to ion diffusion, resulting in poor ion/charge carrier transport properties and slow response speed. Herein, it is proposed to construct small-molecule-based supramolecular polymers to address these issues. A molecule, namely TDPP-RD-G7 is designed, which exhibits J-type self-assembling behaviors and can form supramolecular polymers in solution and conjugated-polymer-like networks in solid state. More importantly, the porous supramolecular polymer networks allow fast ion diffusion and greatly increase the device response speeds. As a result, the TDPP-RD-G7 exhibits record fast response speeds (τon/τoff) of 10.5/0.32 ms with high figure-of-merit (µC*) of 5.88 F cm−1 V−1 s−1 in small-molecule OECTs. This work reveals the possible reasons that hinder the response speeds in small-molecule OECTs and demonstrates a new “supramolecular polymer” approach to high-performance and fast-response small-molecule-based OECTs.  相似文献   

14.
    
Organic electrochemical transistors (OECTs) have the potential to revolutionize the field of organic bioelectronics. To date, most of the reported OECTs include p-type (semi-)conducting polymers as the channel material, while n-type OECTs are yet at an early stage of development, with the best performing electron-transporting materials still suffering from low transconductance, low electron mobility, and slow response time. Here, the high electrical conductivity of multi-walled carbon nanotubes (MWCNTs) and the large volumetric capacitance of the ladder-type π-conjugated redox polymer poly(benzimidazobenzophenanthroline) (BBL) are leveraged to develop n-type OECTs with record-high performance. It is demonstrated that the use of MWCNTs enhances the electron mobility by more than one order of magnitude, yielding fast transistor transient response (down to 15 ms) and high μC* (electron mobility × volumetric capacitance) of about 1 F cm?1 V?1 s?1. This enables the development of complementary inverters with a voltage gain of >16 and a large worst-case noise margin at a supply voltage of <0.6 V, while consuming less than 1 µW of power.  相似文献   

15.
    
A series of donor–acceptor polymers incorporating the thieno[3,2‐b]thiophene‐2,5‐dione (TTD) acceptor unit and different donor units are synthesized. The synthesis of a TTD‐based key monomer, 3,6‐bis(5‐bromo‐4‐alkylthiophen‐2‐yl)thieno[3,2‐b]thiophene‐2,5‐dione, is successfully improved to afford higher total yield with less reaction steps (42%/4 steps) than those previously reported (14%/7 steps). The polymers exhibit low‐lying lowest unoccupied molecular orbital (LUMO) energy levels of around −3.8 eV and highest occupied molecular orbital (HOMO) energy levels ranging from −5.49 to −5.14 eV. Organic field‐effect transistors based on the polymers exhibit ambipolar characteristics with high hole and electron mobilities in the order of 10−1 cm2 V−1 s−1 in air. These high mobilities can be attributed to the formation of highly crystalline lamellar structure with preferential edge‐on orientation of the polymer thin films. Interestingly, the ratio of the electron to hole mobilities decreases with the extension of the donor units. This can be explained by the distribution of HOMOs and LUMOs along the backbones. Additionally, complementary inverters using the polymers with well‐balanced ambipolar characteristics exhibit sharp switching characteristics with high gain of ≈140 at the supply voltage of 40 V.  相似文献   

16.
仪明东  张宁  解令海  黄维 《半导体学报》2015,36(10):104001-6
在本文中,我们利用钛青铜(CuPc)和氟化钛青铜(F16CuPc)作为空穴传输层和电子传输层的制备了具有异质结结构的有机场效应晶体管(OFETs)。与单层的F16CuPc晶体管相比,异质结结构的晶体管的电子迁移率从3.1×10-3cm2/Vs提高至8.7×10-3cm2/vs,然而,空穴的传输行为却没有被观测到。为了提高空穴的注入能力,我们利用MoO3对源-漏电极进行了修饰,有效地改善了空穴注入。并进一步证实了MoO3的引入使得器件的接触电阻变小,平衡了电子和空穴的注入,从而最终实现了器件的双极性传输。  相似文献   

17.
    
Organic integrated circuits have emerged as potential candidates for next-generation computing technology because of their low-cost production, light weight, and mechanical flexibility. However, the incompatibility of organic devices with modern lithographic techniques leads to a major bottleneck, that is, low integration density. Herein, it is attempted to solve this issue by developing an organic quaternary inverter that exhibits four distinguishable logic states and thus, can significantly improve the level of device integration. The key component of the inverter is a double-peaked antiambipolar transistor (DAAT) with a double sequential negative differential transconductance characteristic. First, the DAAT is developed by employing two lateral p-n heterojunctions, namely C8-BTBT/PTCDI-C8 and C8-BTBT/PhC2-BQQDI, in which three distinct conducting paths are produced in a step-by-step manner in accordance with the increase in the gate voltage (VG). Next, the quaternary inverter circuit is implemented by connecting the DAAT with an n-type transistor. The inverter exhibits four logic states with a complete drain voltage to ground voltage sweep. Finally, a strategy of optimizing the thickness of the PTCDI-C8 layer to improve the voltage transfer characteristics of the quaternary inverters is demonstrated. This study, thus, represents a step toward the development of high-performance organic integrated circuits.  相似文献   

18.
    
The two small molecules, quinoidal bithiophene (QBT) and quinoidal biselenophene (QBS), are designed based on a quinoid structure, and synthesized via a facile synthetic route. These quinoidal molecules have a reduced band gap and an amphoteric redox behavior, which is caused by an extended delocalization. Due to such properties, organic field‐effect transistors based on QBT and QBS have shown balanced ambipolar characteristics. After thermal annealing, the performances of the devices are enhanced by an increase in crystallinity. The field‐effect hole and electron mobilities are measured to be 0.031 cm2 V?1 s?1 and 0.005 cm2 V?1 s?1 for QBT, and 0.055 cm2 V?1 s?1 and 0.021 cm2 V?1 s?1 for QBS, respectively. In addition, we investigate the effect of chalcogen atoms (S and Se) on the molecular properties. The optical, electrochemical properties and electronic structures are mainly dominated by the quinoidal structure, whereas molecular properties are scarcely affected by either type of chalcogen atom. The main effect of the chalcogen atoms is ascribed to the difference of crystallinity. Due to a strong intermolecular interaction of the selenophene, QBS exhibits a higher degree of crystallinity, which leads to an enhancement of both hole and electron mobilities. Consequently, these types of quinoidal molecules are found to be promising for use as ambipolar semiconductors.  相似文献   

19.
    
Based on bottom‐up assembly of highly variable neural cells units, the nervous system can reach unequalled level of performances with respect to standard materials and devices used in microelectronic. Reproducing these basic concepts in hardware could potentially revolutionize materials and device engineering which are used for information processing. Here, an innovative approach that relies on both iono‐electronic materials and intrinsic device physics to show pattern classification out of a 12‐unit biosensing array is presented. The reservoir computing and learning concept to demonstrate relevant computing based on the ionic dynamics in 400 nm channel‐length organic electrochemical transistor is used. It is shown that this approach copes efficiently with the high level of variability obtained by bottom‐up fabrication using a new electropolymerizable polymer, which enables iono‐electronic device functionality and material stability in the electrolyte. The effect of the array size and variability on the performances for a real‐time classification task paving the way to new embedded sensing and processing approaches is investigated.  相似文献   

20.
    
The effects of using a blocking dielectric layer and metal nanoparticles (NPs) as charge‐trapping sites on the characteristics of organic nano‐floating‐gate memory (NFGM) devices are investigated. High‐performance NFGM devices are fabricated using the n‐type polymer semiconductor, poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)} (P(NDI2OD‐T2)), and various metal NPs. These NPs are embedded within bilayers of various polymer dielectrics (polystyrene (PS)/poly(4‐vinyl phenol) (PVP) and PS/poly(methyl methacrylate) (PMMA)). The P(NDI2OD‐T2) organic field‐effect transistor (OFET)‐based NFGM devices exhibit high electron mobilities (0.4–0.5 cm2 V?1 s?1) and reliable non‐volatile memory characteristics, which include a wide memory window (≈52 V), a high on/off‐current ratio (Ion/Ioff ≈ 105), and a long extrapolated retention time (>107 s), depending on the choice of the blocking dielectric (PVP or PMMA) and the metal (Au, Ag, Cu, or Al) NPs. The best memory characteristics are achieved in the ones fabricated using PMMA and Au or Ag NPs. The NFGM devices with PMMA and spatially well‐distributed Cu NPs show quasi‐permanent retention characteristics. An inkjet‐printed flexible P(NDI2OD‐T2) 256‐bit transistor memory array (16 × 16 transistors) with Au‐NPs on a polyethylene naphthalate substrate is also fabricated. These memory devices in array exhibit a high Ion/Ioff (≈104 ± 0.85), wide memory window (≈43.5 V ± 8.3 V), and a high degree of reliability.  相似文献   

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