Organic electrochemical transistors(OECTs) exhibit significant potential for applications in healthcare and human-machine interfaces, due to their tunable synthesis, facile deposition, and excellent biocompatibility. ...Organic electrochemical transistors(OECTs) exhibit significant potential for applications in healthcare and human-machine interfaces, due to their tunable synthesis, facile deposition, and excellent biocompatibility. Expanding OECTs to the fexible devices will significantly facilitate stable contact with the skin and enable more possible bioelectronic applications. In this work,we summarize the device physics of fexible OECTs, aiming to offer a foundational understanding and guidelines for material selection and device architecture. Particular attention is paid to the advanced manufacturing approaches, including photolithography and printing techniques, which establish a robust foundation for the commercialization and large-scale fabrication. And abundantly demonstrated examples ranging from biosensors, artificial synapses/neurons, to bioinspired nervous systems are summarized to highlight the considerable prospects of smart healthcare. In the end, the challenges and opportunities are proposed for fexible OECTs. The purpose of this review is not only to elaborate on the basic design principles of fexible OECTs, but also to act as a roadmap for further exploration of wearable OECTs in advanced bio-applications.展开更多
The development of various artificial electronics and machines would explosively increase the amount of information and data,which need to be processed via in-situ remediation.Bioinspired synapse devices can store and...The development of various artificial electronics and machines would explosively increase the amount of information and data,which need to be processed via in-situ remediation.Bioinspired synapse devices can store and process signals in a parallel way,thus improving fault tolerance and decreasing the power consumption of artificial systems.The organic field effect transistor(OFET)is a promising component for bioinspired neuromorphic systems because it is suitable for large-scale integrated circuits and flexible devices.In this review,the organic semiconductor materials,structures and fabrication,and different artificial sensory perception systems functions based on neuromorphic OFET devices are summarized.Subsequently,a summary and challenges of neuromorphic OFET devices are provided.This review presents a detailed introduction to the recent progress of neuromorphic OFET devices from semiconductor materials to perception systems,which would serve as a reference for the development of neuromorphic systems in future bioinspired electronics.展开更多
Organicfield-effect transistors(OFETs)show great application potential in organic electronic and optoelectronicfields due to their excellent mechanicalflexibility,low cost,and solution processing.However,grain boundaries...Organicfield-effect transistors(OFETs)show great application potential in organic electronic and optoelectronicfields due to their excellent mechanicalflexibility,low cost,and solution processing.However,grain boundaries(GBs)disrupt the aggrega-tion state of organic semiconductor(OSC)films and hinder electrical performance and stability,which limits the application of OFETs.Besides,the sensitive nature of GBs is widely used in sensing,but detailed descriptions of the GBs are scarce.This review aims tofill this knowledge gap.The role of GBs and their effect on the per-formance and stability of OFETs are analyzed,followed by a detailed summary of the characterization of GBs.Then,strategies for suppressing the negative effects of GBs and utilizing the sensitive nature of GBs for application are proposed.Finally,potential research directions for GBs in OFETs are discussed.展开更多
Poly(3,4-ethylenedioxyethiophene)-polystyrene sulfonic acid(PEDOT:PSS)/polyallyl dimethyl ammonium chloride modified reduced graphene oxide(PDDA-rGO)was layer by layer self-assembled on the cotton fiber.The surface mo...Poly(3,4-ethylenedioxyethiophene)-polystyrene sulfonic acid(PEDOT:PSS)/polyallyl dimethyl ammonium chloride modified reduced graphene oxide(PDDA-rGO)was layer by layer self-assembled on the cotton fiber.The surface morphology and electric property was investigated.The results confirmed the dense membrane of PEDOT:PSS and the lamellar structure of PDDA-rGO on the fibers.It has excellent electrical conductivity and mechanical properties.The fiber based electrochemical transistor(FECTs)prepared by the composite conductive fiber has a maximum output current of 8.7 mA,a transconductance peak of 10 mS,an on time of 1.37 s,an off time of 1.6 s and excellent switching stability.Most importantly,the devices by layer by layer self-assembly technology opens a path for the true integration of organic electronics with traditional textile technologies and materials,laying the foundation for their later widespread application.展开更多
Tactile and temperature sensors are the key components for e-skin fabrication.Organic transistors,a kind of intrinsic logic devices with diverse internal configurations,offer a wide range of options for sensor design ...Tactile and temperature sensors are the key components for e-skin fabrication.Organic transistors,a kind of intrinsic logic devices with diverse internal configurations,offer a wide range of options for sensor design and have played a vital role in the fabrication of e-skin-oriented tactile and temperature sensors.This research field has attained tremendous advancements,both in terms of materials design and device architecture,thereby leading to excellent performance of resulting tactile/temperature sensors.Herein,a systematic review of organic transistor-based tactile and temperature sensors is presented to summarize the latest progress in these devices.Particularly,we focus on spotlighting various device structures,underlying mechanisms and their performance.Lastly,an outlook for the future development of these devices is briefly discussed.We anticipate that this review will provide a quick overview of such a rapidly emerging research direction and attract more dedicated efforts for the development of next-generation sensing devices towards e-skin fabrication.展开更多
The development of fabrication method for flexible thin organic electronic device is highly important for the flexible and wearable products. Herein, we develop a facile peel-off method to transfer organic thin film t...The development of fabrication method for flexible thin organic electronic device is highly important for the flexible and wearable products. Herein, we develop a facile peel-off method to transfer organic thin film to various substrates. In this strategy, polyacrylonitrile (PAN) film can be easily peeled offwith trace water and further transferred to various substrates. Using PAN as supporting and dielectric layers, high performance flexible organic transistors are fabricated. Remarkably, the method uses only micro volume water as an assist to peel off PAN film, which reduces the risk of contamination by solvent and greatly contributes to the performance maintenance.展开更多
In this contribution, we report on the effect of pentacene thickness and temperature on the performance of top gate transistors. We first investigated the temperature dependence of the transport properties in the temp...In this contribution, we report on the effect of pentacene thickness and temperature on the performance of top gate transistors. We first investigated the temperature dependence of the transport properties in the temperature range of 258 K - 353 K. The electrical characteristics showed that the threshold voltage (VT) and the onset voltage (Von) remain unchanged. However, the subthreshold current (Ioff), the on-current (Ion) and the field effect mobility (μ) are highly affected with a slight deterioration of subthreshold slope. We observed Arrhenius-like behavior suggesting a thermally activated mobility with an activation energy EA = 68 meV. Moreover the dependence of the charge carrier mobility on the organic semiconductor thickness has also been studied. The mobility decreased as the pentacene thickness increases whereas the threshold voltage and Ioff current remain minimally affected. In order to understand the transport properties and in view to put in light morphology peculiarities of pentacene, AFM images were performed. It turns out that the pentacene grain sizes are smaller and disorganized as the film thickness increases, and charge carriers are more prone to be trapped, leading to decrease the field effect mobility and the Ion current. The devices were also tested under bias stress and the transistors with low thicknesses exhibited a relatively good electrical stability compared to those with high pentacene thicknesses. This work points out the influence of temperature, semiconductor thickness and bias stress effect on the device performance and stability of transistor using top gate configuration.展开更多
Fabrication of ambipolar organic field-effect transistors (OFETs) is essential for the achievement of an organic complementary logic circuit. Ambipolar transports in OFETs with heterojunction structures are realized...Fabrication of ambipolar organic field-effect transistors (OFETs) is essential for the achievement of an organic complementary logic circuit. Ambipolar transports in OFETs with heterojunction structures are realized.We select pentacene as a P-type material and N,N'-bis(4-trifluoromethylben-zyl)perylene-3,4,9,10-tetracarboxylic diimide (PTCDI-TFB) as a n-type material in the active layer of the OFETs.The field-effect transistor shows highly air-stable ambipolar characteristics with a field-effect hole mobility of 0.18 cm^2/(V·s) and field-effect electron mobility of 0.031 cm^2/(V·s).Furthermore the mobility only slightly decreases after being exposed to air and remains stable even for exposure to air for more than 60 days.The high electron affinity of PTCDI-TFB and the octadecyltrichlorosilane (OTS) self-assembly monolayer between the SiO2 gate dielectric and the organic active layer result in the observed air-stable characteristics of OFETs with high mobility.The results demonstrate that using the OTS as a modified gate insulator layer and using high electron affinity semiconductor materials are two effective methods to fabricate OFETs with air-stable characteristics and high mobility.展开更多
Pentacene organic field-effect transistors (OFETs) based on single- or double-layer biocompatible dielectrics of poly(methyl methacrylate) (PMMA) and/or silk fibroin (SF) are fabricated. Compared with those de...Pentacene organic field-effect transistors (OFETs) based on single- or double-layer biocompatible dielectrics of poly(methyl methacrylate) (PMMA) and/or silk fibroin (SF) are fabricated. Compared with those devices based on sin- gle PMMA or SF dielectric or SF/PMMA bilayer dielectric, the OFETs with biocompatible PMMA/SF bilayer dielectric exhibit optimal performance with a high field-effect mobility of 0.21 cm2/Vs and a current on/off ratio of 1.5 × 104. By investigating the surface morphology of the pentacene active layer through atom force microscopy and analyzing the elec- trical properties, the performance enhancement is mainly attributed to the crystallization improvement of the pentacene and the smaller interface trap density at the dielectric/organic interface. Meanwhile, a low contact resistance also indicates that a good electrode/organic contact is formed, thereby assisting the performance improvement of the OFET.展开更多
A top-contact organic field-effect transistor (OFET) is fabricated by adopting a pentacene/1,11-bis(di-4- tolylaminophenyl) cyclohexane (TAPC) heterojunction structure and inserting an MoO3 buffer layer between ...A top-contact organic field-effect transistor (OFET) is fabricated by adopting a pentacene/1,11-bis(di-4- tolylaminophenyl) cyclohexane (TAPC) heterojunction structure and inserting an MoO3 buffer layer between the TAPC organic semiconductor layer and the source/drain electrode. The performances of the heterojunction OFET, including output current, field-effect mobility, and threshed voltage~ are all significantly improved by introducing the MoO3 thin buffer layer. The performance improvement of the modified heterojunction OFET is attributed to a better contact formed at the Au/TAPC interface due to the MoO3 thin buffer layer, thereby leading to a remarkable reduction of the contact resistance at the metal/organic interface.展开更多
Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, l...Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.展开更多
Non-chlorinated solvents are highly preferable for organic electronic processing due to their environmentally friendly characteristics. Four different halogen-free solvents, tetrafuran, toluene, meta-xylene and 1,2,4-...Non-chlorinated solvents are highly preferable for organic electronic processing due to their environmentally friendly characteristics. Four different halogen-free solvents, tetrafuran, toluene, meta-xylene and 1,2,4-trimethyl- benzene, were selected to fabricate n-channel organic thin film transistors (OTFTs) based on 3-hexylundecyl sub- stituted naphthalene diimides fused with (1,3-dithiol-2-ylidene)malononitrile groups (NDI3HU-DTYM2). The OTFTs based on NDI3HU-DTYM2 showed electron mobility of up to 1.37 cm2-V-1·s -1 under ambient condition. This is among the highest device performance for n-channel OTFTs processed from halogen-free solvents. The dif- ferent thin-film morphologies, from featureless low crystalline morphology to well-aligned nanofibres, have a great effect on the device performance. These results might shed some light on solvent selection and the resulting solution process for organic electronic devices.展开更多
Glutaraldehyde(GA)crosslinked chitosan(CHIT)was modified on nylon fibers.Afterwards,pyrrole was in-situ polymerized on the surface of the CHIT/Nylon fiber.The SEM and FT-IR results show that the functional fiber is su...Glutaraldehyde(GA)crosslinked chitosan(CHIT)was modified on nylon fibers.Afterwards,pyrrole was in-situ polymerized on the surface of the CHIT/Nylon fiber.The SEM and FT-IR results show that the functional fiber is successfully prepared,and the obtained polypyrrole(PPy)presents nanorods morphology on the fiber surface.The mechanical properties of the fibers were studied by Instron.The organic electrochemical transistors based on PPy/Nylon fiber,PPy/CHIT/Nylon fiber,and PPy/GA-CHIT/Nylon fiber as channels were prepared and their transistors performance was compared.It is found that PPy/GA-CHIT/Nylon fiber-based transistor has great output,transfer,transient curves,and excellent transconductance of 6.8 mS,providing a new platform for the field of wearable devices.Furthermore,the study introduces chitosan material with excellent biocompatibility,which makes prepared transistors also have potential applications in the field of biosensing.展开更多
With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and c...With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and charge carrier mobility in pentacene and regioregular poly (3-hexylthiophene) (RR-P3HT) field-effect transistors. On the basis of the results of surface morphologies and electrical properties, we presume that the charge carrier mobility is largely related to the morphology of the organic active layer. We observe that the change trends of the surface morphologies (average size and average roughness) of pentacene and RR-P3HT thin films are mutually opposite, as the thickness of the organic layer increases. Further, we demonstrate that the change trends of the field-effect mobilities of pentacene and RR-P3HT FETs are also opposite to each other, as the thickness of the organic layer increases within its limit.展开更多
This paper reports that the organic field-effect transistors with hybrid contact geometry were fabricated, in which the top electrodes and the bottom electrodes were combined in parallel resistances within one transis...This paper reports that the organic field-effect transistors with hybrid contact geometry were fabricated, in which the top electrodes and the bottom electrodes were combined in parallel resistances within one transistor. With the facility of the novel structure, the difference of contact resistance between the top contact geometry and the bottom contact geometry was studied. The hybrid contact devices showed similar characteristics with the top contact configuration devices, which provide helpful evidence on the lower contact resistance of the top contact configuration device. The origin of the different contact resistance between the top contact device and the bottom contact device was discussed.展开更多
The properties of top-contact organic thin-film transistors (TC-OTFTs) using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline (BCP) as a hole-blocking interlayer have been improved significantly and a ...The properties of top-contact organic thin-film transistors (TC-OTFTs) using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline (BCP) as a hole-blocking interlayer have been improved significantly and a BCP interlayer was inserted into the middle of the pentacene active layer. This paper obtains a fire-new transport mode of an OTFT device with double-conductible channels. The accumulation and transfer of the hole carriers arc limited by the BCP interlayer in the vertical region of the channel. A huge amount of carriers is located not only at the interface between pentacene and the gate insulator, but also at the two interfaces of pentacene/BCP interlayer and pentacene/gate insulator, respectively. The results suggest that the BCP interlayer may be useful to adjust the hole accumulation and transfer, and can increase the hole mobility and output current of OTFTs. The TC-OTFTs with a BCP interlayer at VDS = --20 V showed excellent hole mobility μFE and threshold voltage VTH of 0.58 cm^2/(V-s) and -4.6 V, respectively.展开更多
The luminescence intensity regulation of organic light-emitting transistor(OLED)device can be achieved effectively by the combination of graphene vertical field effect transistor(GVFET)and OLED.In this paper,we fabric...The luminescence intensity regulation of organic light-emitting transistor(OLED)device can be achieved effectively by the combination of graphene vertical field effect transistor(GVFET)and OLED.In this paper,we fabricate and characterize the graphene vertical field-effect transistor with gate dielectric of ion-gel film,confirming that its current switching ratio reaches up to 102.Because of the property of high light transmittance in ion-gel film,the OLED device prepared with graphene/PEDOT:PSS as composite anode exhibits good optical properties.We also prepare the graphene vertical organic light-emitting field effect transistor(GVOLEFET)by the combination of GVFET and graphene OLED,analyzing its electrical and optical properties,and confirming that the luminescence intensity can be significantly changed by regulating the gate voltage.展开更多
This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolit...This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolithographic and etching processes, parts of the passivation layer are etched off to form source/drain electrode patterns. Combined with conventional evaporation and lift-off techniques, organic field effect transistors with a top contact are fabricated suc- cessfully, whose properties are comparable to those prepared with the shadow mask method and one order of magnitude higher than the bottom contact devices fabricated by using a photolithographic process.展开更多
The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C6...The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C60 modification, the injection barrier is lowered and the contact resistance is reduced. Thus, the field-effect mobility increases from 0.12 to 0.52 cm2/(V.s). It means that inserting a C60 ultra thin layer is a good method to improve the organic thin film transistor (OTFT) performance. The output curve is simulated by using a charge drift model. Considering the contact effect, the field effect mobility is improved to 1.15 cm2/(V-s). It indicates that further reducing the contact resistance of OTFTs should be carried out.展开更多
In this article, an organic thin-film field-effect transistor (OTFFET) with top-gate and bottom-contact geometry based on pentacene as the active layer is fabricated. The experimental data of the I-V are obtained fr...In this article, an organic thin-film field-effect transistor (OTFFET) with top-gate and bottom-contact geometry based on pentacene as the active layer is fabricated. The experimental data of the I-V are obtained from the OTFFET device. The alternating-current (AC) resistance value of the OTFFET device is calculated using the derivation method from the experimental data, and the AC resistance trend curves of the OTFFET device are obtained with the region fitting method. We analyse the characteristics of the OTFFET device with an AC resistance trend curve. To discover whether it has a high resistance, it is proposed to judge the region of the source/drain voltage (VDs) less than the transition voltage, thereby determining whether the contact between the metal electrode and the organic semiconductor layer of the OTFFET device is Ohmic or non-Ohmic. The theoretical analysis shows that the field-effect mobility and the AC resistance are in reverse proportion. Therefore, we point out that reducing AC resistance is necessary if field-effect mobility is to be improved.展开更多
基金sponsored by the Regional Joint Fund of the National Science Foundation of China via Grant No. U21A20492the National Natural Science Foundation of China (NSFC) via Grant No. 62275041+2 种基金the Sichuan Science and Technology Program via Grant Nos. 2022YFH0081, 2022YFG0012 and 2022YFG0013the Sichuan Youth Software Innovation Project Funding via Grant No. MZGC20230068the Sichuan Province Key Laboratory of Display Science and Technology。
文摘Organic electrochemical transistors(OECTs) exhibit significant potential for applications in healthcare and human-machine interfaces, due to their tunable synthesis, facile deposition, and excellent biocompatibility. Expanding OECTs to the fexible devices will significantly facilitate stable contact with the skin and enable more possible bioelectronic applications. In this work,we summarize the device physics of fexible OECTs, aiming to offer a foundational understanding and guidelines for material selection and device architecture. Particular attention is paid to the advanced manufacturing approaches, including photolithography and printing techniques, which establish a robust foundation for the commercialization and large-scale fabrication. And abundantly demonstrated examples ranging from biosensors, artificial synapses/neurons, to bioinspired nervous systems are summarized to highlight the considerable prospects of smart healthcare. In the end, the challenges and opportunities are proposed for fexible OECTs. The purpose of this review is not only to elaborate on the basic design principles of fexible OECTs, but also to act as a roadmap for further exploration of wearable OECTs in advanced bio-applications.
基金the National Natural Science Foundation of China(U21A20497)Singapore National Research Foundation Investigatorship(Grant No.NRF-NRFI08-2022-0009)。
文摘The development of various artificial electronics and machines would explosively increase the amount of information and data,which need to be processed via in-situ remediation.Bioinspired synapse devices can store and process signals in a parallel way,thus improving fault tolerance and decreasing the power consumption of artificial systems.The organic field effect transistor(OFET)is a promising component for bioinspired neuromorphic systems because it is suitable for large-scale integrated circuits and flexible devices.In this review,the organic semiconductor materials,structures and fabrication,and different artificial sensory perception systems functions based on neuromorphic OFET devices are summarized.Subsequently,a summary and challenges of neuromorphic OFET devices are provided.This review presents a detailed introduction to the recent progress of neuromorphic OFET devices from semiconductor materials to perception systems,which would serve as a reference for the development of neuromorphic systems in future bioinspired electronics.
基金Funding information National Key Research and Development Program,Grant/Award Numbers:2018YFA0703200,2022YFF1202700National Natural Science Foundation of China,Grant/Award Numbers:52225304,52073210,52203236,52121002Natural Science Foundation of Tanjin City,Grant/Award Numbers:19JCJQJC62600,19JCZDJC37400。
文摘Organicfield-effect transistors(OFETs)show great application potential in organic electronic and optoelectronicfields due to their excellent mechanicalflexibility,low cost,and solution processing.However,grain boundaries(GBs)disrupt the aggrega-tion state of organic semiconductor(OSC)films and hinder electrical performance and stability,which limits the application of OFETs.Besides,the sensitive nature of GBs is widely used in sensing,but detailed descriptions of the GBs are scarce.This review aims tofill this knowledge gap.The role of GBs and their effect on the per-formance and stability of OFETs are analyzed,followed by a detailed summary of the characterization of GBs.Then,strategies for suppressing the negative effects of GBs and utilizing the sensitive nature of GBs for application are proposed.Finally,potential research directions for GBs in OFETs are discussed.
基金Funded by the Key R&D Program of the Science and Technology Department of Hubei Province(No.2022BCE008)。
文摘Poly(3,4-ethylenedioxyethiophene)-polystyrene sulfonic acid(PEDOT:PSS)/polyallyl dimethyl ammonium chloride modified reduced graphene oxide(PDDA-rGO)was layer by layer self-assembled on the cotton fiber.The surface morphology and electric property was investigated.The results confirmed the dense membrane of PEDOT:PSS and the lamellar structure of PDDA-rGO on the fibers.It has excellent electrical conductivity and mechanical properties.The fiber based electrochemical transistor(FECTs)prepared by the composite conductive fiber has a maximum output current of 8.7 mA,a transconductance peak of 10 mS,an on time of 1.37 s,an off time of 1.6 s and excellent switching stability.Most importantly,the devices by layer by layer self-assembly technology opens a path for the true integration of organic electronics with traditional textile technologies and materials,laying the foundation for their later widespread application.
基金supported by the Characteristic Innovation Projects of General Colleges and Universities in Guangdong Province(Grant No.2018KTSCX132)the Natural Science Foundation of Guangdong Province(Grant Nos.2018A030307027,2020A1515011488)+3 种基金the Natural Science Research Special Foundation of Lingnan Normal University(Grant No.ZL2045)the Major Projects of Basic and Application Research in Guangdong Province(Grant No.2017KZDXM055)the Special Fund for Science and Technology Innovation Strategy of Guangdong Guangdong Province(Grant No.2018A03015)Zhanjiang Science and Technology Plan(Grant No.2018A02010).
文摘Tactile and temperature sensors are the key components for e-skin fabrication.Organic transistors,a kind of intrinsic logic devices with diverse internal configurations,offer a wide range of options for sensor design and have played a vital role in the fabrication of e-skin-oriented tactile and temperature sensors.This research field has attained tremendous advancements,both in terms of materials design and device architecture,thereby leading to excellent performance of resulting tactile/temperature sensors.Herein,a systematic review of organic transistor-based tactile and temperature sensors is presented to summarize the latest progress in these devices.Particularly,we focus on spotlighting various device structures,underlying mechanisms and their performance.Lastly,an outlook for the future development of these devices is briefly discussed.We anticipate that this review will provide a quick overview of such a rapidly emerging research direction and attract more dedicated efforts for the development of next-generation sensing devices towards e-skin fabrication.
基金financially supported by the Program for Special Appointment(Eastern Scholar) at Shanghai Institute of Higher Learning (No. 21577086)the National Natural Science Foundation of China(No. 21573277)
文摘The development of fabrication method for flexible thin organic electronic device is highly important for the flexible and wearable products. Herein, we develop a facile peel-off method to transfer organic thin film to various substrates. In this strategy, polyacrylonitrile (PAN) film can be easily peeled offwith trace water and further transferred to various substrates. Using PAN as supporting and dielectric layers, high performance flexible organic transistors are fabricated. Remarkably, the method uses only micro volume water as an assist to peel off PAN film, which reduces the risk of contamination by solvent and greatly contributes to the performance maintenance.
基金the FIRST(Fonds d’Impulsion pour la Recherche Scientifique et Technique)programCEA-MITIC(Centre d’excellence en Mathematiques,Informatique et TIC)for financial support.
文摘In this contribution, we report on the effect of pentacene thickness and temperature on the performance of top gate transistors. We first investigated the temperature dependence of the transport properties in the temperature range of 258 K - 353 K. The electrical characteristics showed that the threshold voltage (VT) and the onset voltage (Von) remain unchanged. However, the subthreshold current (Ioff), the on-current (Ion) and the field effect mobility (μ) are highly affected with a slight deterioration of subthreshold slope. We observed Arrhenius-like behavior suggesting a thermally activated mobility with an activation energy EA = 68 meV. Moreover the dependence of the charge carrier mobility on the organic semiconductor thickness has also been studied. The mobility decreased as the pentacene thickness increases whereas the threshold voltage and Ioff current remain minimally affected. In order to understand the transport properties and in view to put in light morphology peculiarities of pentacene, AFM images were performed. It turns out that the pentacene grain sizes are smaller and disorganized as the film thickness increases, and charge carriers are more prone to be trapped, leading to decrease the field effect mobility and the Ion current. The devices were also tested under bias stress and the transistors with low thicknesses exhibited a relatively good electrical stability compared to those with high pentacene thicknesses. This work points out the influence of temperature, semiconductor thickness and bias stress effect on the device performance and stability of transistor using top gate configuration.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60676033 and 60276026)the Natural Science Foundation of Gansu Province,China (Grant No ZS031-A25-012-G)‘Qing Lan’ Talent Engineering Funds from Lanzhou Jiaotong University,China (Grant No QL-08-18A)
文摘Fabrication of ambipolar organic field-effect transistors (OFETs) is essential for the achievement of an organic complementary logic circuit. Ambipolar transports in OFETs with heterojunction structures are realized.We select pentacene as a P-type material and N,N'-bis(4-trifluoromethylben-zyl)perylene-3,4,9,10-tetracarboxylic diimide (PTCDI-TFB) as a n-type material in the active layer of the OFETs.The field-effect transistor shows highly air-stable ambipolar characteristics with a field-effect hole mobility of 0.18 cm^2/(V·s) and field-effect electron mobility of 0.031 cm^2/(V·s).Furthermore the mobility only slightly decreases after being exposed to air and remains stable even for exposure to air for more than 60 days.The high electron affinity of PTCDI-TFB and the octadecyltrichlorosilane (OTS) self-assembly monolayer between the SiO2 gate dielectric and the organic active layer result in the observed air-stable characteristics of OFETs with high mobility.The results demonstrate that using the OTS as a modified gate insulator layer and using high electron affinity semiconductor materials are two effective methods to fabricate OFETs with air-stable characteristics and high mobility.
基金Project supported by the National Natural Science Foundation of China(Grant No.61177032)the Foundation for Innovation Groups of the National Natural Science Foundation of China(Grant No.61021061)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.ZYGX2010Z004)the Scientific Research Staring Foundation for the Returned Overseas Chinese Scholars of the Education Ministry of China(Grant No.GGRYJJ08-05)
文摘Pentacene organic field-effect transistors (OFETs) based on single- or double-layer biocompatible dielectrics of poly(methyl methacrylate) (PMMA) and/or silk fibroin (SF) are fabricated. Compared with those devices based on sin- gle PMMA or SF dielectric or SF/PMMA bilayer dielectric, the OFETs with biocompatible PMMA/SF bilayer dielectric exhibit optimal performance with a high field-effect mobility of 0.21 cm2/Vs and a current on/off ratio of 1.5 × 104. By investigating the surface morphology of the pentacene active layer through atom force microscopy and analyzing the elec- trical properties, the performance enhancement is mainly attributed to the crystallization improvement of the pentacene and the smaller interface trap density at the dielectric/organic interface. Meanwhile, a low contact resistance also indicates that a good electrode/organic contact is formed, thereby assisting the performance improvement of the OFET.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61071026 and 61177032)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China (Grant No.61021061)+1 种基金the Fundamental Research Fund for the Central Universities of Misistry of Education of China (Grant No.ZYGX2010Z004)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20090185110020)
文摘A top-contact organic field-effect transistor (OFET) is fabricated by adopting a pentacene/1,11-bis(di-4- tolylaminophenyl) cyclohexane (TAPC) heterojunction structure and inserting an MoO3 buffer layer between the TAPC organic semiconductor layer and the source/drain electrode. The performances of the heterojunction OFET, including output current, field-effect mobility, and threshed voltage~ are all significantly improved by introducing the MoO3 thin buffer layer. The performance improvement of the modified heterojunction OFET is attributed to a better contact formed at the Au/TAPC interface due to the MoO3 thin buffer layer, thereby leading to a remarkable reduction of the contact resistance at the metal/organic interface.
基金supported by the National Basic Research Program of China(2013CB933500)National Natural Science Foundation of China(Grant Nos.61422403,51672180,51622306,21673151)+2 种基金Qing Lan ProjectCollaborative Innovation Center of Suzhou Nano Science and Technology(NANO-CIC)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.
基金the "Strategic Priority Research Program" (XDB12010100) and the National Natural Science Foundation of China (51173200 and 21522209), the Ministry of Science and Technology (2011CB932300), and the Chinese Acade- my of Sciences. We thank Professor Steven Abbott for helpful discussion about Hansen Solubility Parameter.
文摘Non-chlorinated solvents are highly preferable for organic electronic processing due to their environmentally friendly characteristics. Four different halogen-free solvents, tetrafuran, toluene, meta-xylene and 1,2,4-trimethyl- benzene, were selected to fabricate n-channel organic thin film transistors (OTFTs) based on 3-hexylundecyl sub- stituted naphthalene diimides fused with (1,3-dithiol-2-ylidene)malononitrile groups (NDI3HU-DTYM2). The OTFTs based on NDI3HU-DTYM2 showed electron mobility of up to 1.37 cm2-V-1·s -1 under ambient condition. This is among the highest device performance for n-channel OTFTs processed from halogen-free solvents. The dif- ferent thin-film morphologies, from featureless low crystalline morphology to well-aligned nanofibres, have a great effect on the device performance. These results might shed some light on solvent selection and the resulting solution process for organic electronic devices.
基金by the Hubei Province Education Department Project(Q20191708)。
文摘Glutaraldehyde(GA)crosslinked chitosan(CHIT)was modified on nylon fibers.Afterwards,pyrrole was in-situ polymerized on the surface of the CHIT/Nylon fiber.The SEM and FT-IR results show that the functional fiber is successfully prepared,and the obtained polypyrrole(PPy)presents nanorods morphology on the fiber surface.The mechanical properties of the fibers were studied by Instron.The organic electrochemical transistors based on PPy/Nylon fiber,PPy/CHIT/Nylon fiber,and PPy/GA-CHIT/Nylon fiber as channels were prepared and their transistors performance was compared.It is found that PPy/GA-CHIT/Nylon fiber-based transistor has great output,transfer,transient curves,and excellent transconductance of 6.8 mS,providing a new platform for the field of wearable devices.Furthermore,the study introduces chitosan material with excellent biocompatibility,which makes prepared transistors also have potential applications in the field of biosensing.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10774013 and 10804006)the National High Technology Research and Development Program of China (Grant No. 2006AA03Z412)+3 种基金the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20070004024)the Research Fund for the Youth Scholars of the Doctoral Program of Higher Education, China (Grant No. 20070004031)the New Star Plan of Science and Technology of Beijing, China(Grant No. 2007A024)the research grants from the Academy of Sciences for the Developing World (Grant No. B08002)
文摘With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and charge carrier mobility in pentacene and regioregular poly (3-hexylthiophene) (RR-P3HT) field-effect transistors. On the basis of the results of surface morphologies and electrical properties, we presume that the charge carrier mobility is largely related to the morphology of the organic active layer. We observe that the change trends of the surface morphologies (average size and average roughness) of pentacene and RR-P3HT thin films are mutually opposite, as the thickness of the organic layer increases. Further, we demonstrate that the change trends of the field-effect mobilities of pentacene and RR-P3HT FETs are also opposite to each other, as the thickness of the organic layer increases within its limit.
基金supported by National Basic Research Program of China (973 Program) (Grant No 2006CB806204)National Natural Science Foundation of China (Grant Nos 60676001,60676008 and 60825403)
文摘This paper reports that the organic field-effect transistors with hybrid contact geometry were fabricated, in which the top electrodes and the bottom electrodes were combined in parallel resistances within one transistor. With the facility of the novel structure, the difference of contact resistance between the top contact geometry and the bottom contact geometry was studied. The hybrid contact devices showed similar characteristics with the top contact configuration devices, which provide helpful evidence on the lower contact resistance of the top contact configuration device. The origin of the different contact resistance between the top contact device and the bottom contact device was discussed.
基金supported by the National High Technology Research and Development Program of China (Grant No 2006AA03Z0412)the National Natural Science Foundation of China (Grant Nos 10774013 and 10804006)+4 种基金the Excellent Doctor’s Science and Technology Innovation Foundation of Beijing Jiaotong University (Grant No 48024)the Foundation of Beijing Jiaotong University (Grant No 2005SM057)the Research Fund for the Youth Scholars of the Doctoral Program of Higher Education (Grant No 20070004031)the Beijing NOVA program (Grant No 2007A024)Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The properties of top-contact organic thin-film transistors (TC-OTFTs) using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline (BCP) as a hole-blocking interlayer have been improved significantly and a BCP interlayer was inserted into the middle of the pentacene active layer. This paper obtains a fire-new transport mode of an OTFT device with double-conductible channels. The accumulation and transfer of the hole carriers arc limited by the BCP interlayer in the vertical region of the channel. A huge amount of carriers is located not only at the interface between pentacene and the gate insulator, but also at the two interfaces of pentacene/BCP interlayer and pentacene/gate insulator, respectively. The results suggest that the BCP interlayer may be useful to adjust the hole accumulation and transfer, and can increase the hole mobility and output current of OTFTs. The TC-OTFTs with a BCP interlayer at VDS = --20 V showed excellent hole mobility μFE and threshold voltage VTH of 0.58 cm^2/(V-s) and -4.6 V, respectively.
基金Project supported by the National Natural Science Foundation of China(Grant No.31872901)the National Key Research and Development Program of China(Grant No.2016YFA0501602).
文摘The luminescence intensity regulation of organic light-emitting transistor(OLED)device can be achieved effectively by the combination of graphene vertical field effect transistor(GVFET)and OLED.In this paper,we fabricate and characterize the graphene vertical field-effect transistor with gate dielectric of ion-gel film,confirming that its current switching ratio reaches up to 102.Because of the property of high light transmittance in ion-gel film,the OLED device prepared with graphene/PEDOT:PSS as composite anode exhibits good optical properties.We also prepare the graphene vertical organic light-emitting field effect transistor(GVOLEFET)by the combination of GVFET and graphene OLED,analyzing its electrical and optical properties,and confirming that the luminescence intensity can be significantly changed by regulating the gate voltage.
基金Project supported by the National Basic Research Program of China (Grant Nos. 2011CB808404 and 2009CB939703)the National Natural Science Foundation of China (Grant Nos. 10974074,90607022,60676001,60676008,and 60825403)
文摘This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolithographic and etching processes, parts of the passivation layer are etched off to form source/drain electrode patterns. Combined with conventional evaporation and lift-off techniques, organic field effect transistors with a top contact are fabricated suc- cessfully, whose properties are comparable to those prepared with the shadow mask method and one order of magnitude higher than the bottom contact devices fabricated by using a photolithographic process.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10774013,10974013,60978060 and 10804006)the Research Fund for the Doctoral Program of Higher Education,China(Grant Nos.20090009110027,20070004024 and 20070004031)+1 种基金the Beijing Municipal Science and Technology Commission(Grant No.1102028)the National Basic Research Program of China(Grant No.2010CB327704)
文摘The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C60 modification, the injection barrier is lowered and the contact resistance is reduced. Thus, the field-effect mobility increases from 0.12 to 0.52 cm2/(V.s). It means that inserting a C60 ultra thin layer is a good method to improve the organic thin film transistor (OTFT) performance. The output curve is simulated by using a charge drift model. Considering the contact effect, the field effect mobility is improved to 1.15 cm2/(V-s). It indicates that further reducing the contact resistance of OTFTs should be carried out.
基金Project supported by the National Grand Fundamental Research 973 Program of China (Grant No. 2010CB327704)the National Natural Science Foundation of China (Grant Nos. 10974013 and 60978060)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20090009110027)the Natural Science Foundation of Beijing,China (Grant No. 1102028)the National Natural Science Foundation for Distinguished Young Scholars (Grant No. 60825407)Beijing Municipal Science and Technology Commission (Grant No. Z090803044009001)
文摘In this article, an organic thin-film field-effect transistor (OTFFET) with top-gate and bottom-contact geometry based on pentacene as the active layer is fabricated. The experimental data of the I-V are obtained from the OTFFET device. The alternating-current (AC) resistance value of the OTFFET device is calculated using the derivation method from the experimental data, and the AC resistance trend curves of the OTFFET device are obtained with the region fitting method. We analyse the characteristics of the OTFFET device with an AC resistance trend curve. To discover whether it has a high resistance, it is proposed to judge the region of the source/drain voltage (VDs) less than the transition voltage, thereby determining whether the contact between the metal electrode and the organic semiconductor layer of the OTFFET device is Ohmic or non-Ohmic. The theoretical analysis shows that the field-effect mobility and the AC resistance are in reverse proportion. Therefore, we point out that reducing AC resistance is necessary if field-effect mobility is to be improved.