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
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
The compatibility of the gate dielectrics with semiconductors is vital for constructing efficient conducting channel for high charge transport.However,it is still a highly challenging mission to clearly clarify the re...The compatibility of the gate dielectrics with semiconductors is vital for constructing efficient conducting channel for high charge transport.However,it is still a highly challenging mission to clearly clarify the relationship between the dielectric layers and the chemical structure of semiconductors,especially vacuum-deposited small molecules.Here,interfacial molecular screening of polyimide(Kapton)dielectric in organic field-effect transistors(OFETs)is comprehensively studied.It is found that the semiconducting small molecules with alkyl side chains prefer to form a high-quality charge transport layer on polyimide(PI)dielectrics compared with the molecules without alkyl side chains.On this basis,the fabricated transistors could reach the mobility of 1.2 cm^(2) V^(−1)s^(−1) the molecule with alkyl side chains on bare PI dielectric.What is more,the compatible semiconductor and dielectric would further produce a low activation energy(E_(A))of 3.01 meV towards efficient charge transport even at low temperature(e.g.,100 K,0.9 cm^(2) V^(−1)s^(−1)).Our research provides a guiding scheme for the construction of high-performance thin-film field-effect transistors based on PI dielectric layer at room and low temperatures.展开更多
Diketopyrrolopyrrole(DPP)is one of the most promising building blocks for constructing polymer semiconductors with high charge-carrier mobilities in organic field-effect transistors(OFETs).In this study,a novel DPP-ba...Diketopyrrolopyrrole(DPP)is one of the most promising building blocks for constructing polymer semiconductors with high charge-carrier mobilities in organic field-effect transistors(OFETs).In this study,a novel DPP-based conjugated polymer,PDPPy-BDD,was designed and synthesized.The ambipolar field-effect transistor characteristics were realized with the average hole and electron mobilities of 3.5×10^(-3)and 3.07×10^(-2)cm^(2)V^(-1)s^(-1),respectively.Both the hole and electron mobilities could be successfully en-hanced by using a tetramethylammonium iodide(NMe4l)additive.Such an enhancement was attributed to the formation of stronger interchainπ-πstackings,the weakening of the face-on packing orientation in the thin film state,and the higher channel conductivi-ties in the OFETs.展开更多
The recent progress in the design and synthesis of high-performance donor-acceptor conjugated polymeric semiconducting materials is reviewed from the perspective of multiscale structures.The multiscale of conjugated p...The recent progress in the design and synthesis of high-performance donor-acceptor conjugated polymeric semiconducting materials is reviewed from the perspective of multiscale structures.The multiscale of conjugated polymers is from the primary one-dimensional polymer molecular scale to the secondary polymer-chains interaction scale,and then to the tertiary polymer aggregate scale.This review focuses on the design and synthesis of polymer molecules,proposes new classification rules,and rationally summarizes the design strategies and modulation methods of polymers.We describe the recent progress from these three aspects:(1)the modification ofπ-conjugated backbone,(2)the evolution of the polymerization methods,and(3)the regulation of aggregate-state structure.展开更多
Biosensors based on organic field-effect transistors(OFETs)are one of the most promising electronic devices for emerging bioanalytical applications.The selection of organic semiconductors(OSCs)is essential to improve ...Biosensors based on organic field-effect transistors(OFETs)are one of the most promising electronic devices for emerging bioanalytical applications.The selection of organic semiconductors(OSCs)is essential to improve the sensitivity and reliability of this kind of biosensors.Given the good field effect performance and tunable structures of D-A type conjugated polymers,here,we design two D-A type copolymers[P(BDT-co-DPP2T-ThC_(2))and P(BDT-co-DPP2T-Th)],which are applied as the OSC layers.With carcinoembryonic antigen antibody(anti-CEA)adsorbed onto the OSC layers as the recognition sites,OFETs based biosensors for CEA detection are developed.The experimental findings support that the attachment of ester side groups onto the polymer backbone[as for P(BDT-co-DPP2T-ThC_(2))]is favorable for improved solubility and filming properties of the polymer.The introduction of ester side groups affects molecular stacking and enhances intermolecular forces.The resultant devices show high charge mobility and antibody adsorption ability,both of which are critical for sensitive and facile detection of CEA biomarkers.The reliable determination of CEA down to the picomolar level is determined.It is expected that this kind of biosensors fabricated by D-A type conducting polymers will open new avenues toward the early diagnosis,real-time monitoring and treatment of future cancer diseases.展开更多
The fundamental I-V formula of an organic field effect transistor(OFET)is improved to overcome the divergence of the integrand,so it is very convenient for both numerical calculations and analytic derivations.The anal...The fundamental I-V formula of an organic field effect transistor(OFET)is improved to overcome the divergence of the integrand,so it is very convenient for both numerical calculations and analytic derivations.The analytic I-V formulae are derived based on the exponential mobility model and power-function mobility model,respectively,and the derived analytic formulae are applied to three OFET devices.The results calculated from the reformulated analytic I-V formulae taking in exponential and power function mobility models are all in good agreement with the experimental I-V data.The parameters μ_(0) and γ that are extracted from the mobility model and fitted by experimental data show simple Arrhenius temperature dependence and inverse linear relationship with temperature,respectively.These findings are very useful for practical applications and device simulations.展开更多
Organic field-effect transistors(OFETs)refer to field-effect transistors that use organic semiconductors as channel materials.Owing to the advantages of organic materials such as solution processability and intrinsic ...Organic field-effect transistors(OFETs)refer to field-effect transistors that use organic semiconductors as channel materials.Owing to the advantages of organic materials such as solution processability and intrinsic flexibility,OFETs are expected to be applicable in emergent technologies including wearable electronics and sensors,flexible displays,internet-of-things,neuromorphic computing,etc.Improving the electrical performance and developing multifunctionalities of OFETs are two major and closely relevant aspects for OFETs-related research.The former one aims for investigating the device physics and expanding the horizons of OFETs,while the later one is critical for leading OFETs into practical and emergent applications.The development in each of the two aspects would undoubtfully promote the other and bring more confidence for future development of OFETs.Hence,this review is divided into two parts that respectively summarize the recent progress in high-performance OFETs and multifunctional OFETs.展开更多
The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas w...The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.展开更多
1 Restults Tetrathiafulvalene (TTF) and its derivatives have been extensively investigated in the field of organic conductors and superconductors since 1973. Recently, their application in organic field-effect transis...1 Restults Tetrathiafulvalene (TTF) and its derivatives have been extensively investigated in the field of organic conductors and superconductors since 1973. Recently, their application in organic field-effect transistors (OFETs) has attracted considerable attention. So far, on the one hand, the fabrication techniques of the TTF-based FETs have been primarily limited to high vacuum evaporation, which is a relatively expensive process. On the other hand, low FET performances, such as the low on/off ratio...展开更多
A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoi...A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoided. The photo-cross-linker, BBP-4, was added into host polymers by simple solution blending process, which was capable of abstracting hydrogen atoms from polymers containing active C--H groups upon exposure to ultraviolet (UV) radiation. The cross-linking can be completed with a relatively long wavelength UV light (365 nm). The approach has been applied to methacrylate and styrenic polymers such as commercial poly(methylmethacrylate) (PMMA), poly(iso-butylmethacrylate) (PiBMA) and poly(4-methylstyrene) (PMS). The cross-linked networks enhanced dielectric properties and solvent resistance of the thin films. The bottom-gate organic field-effect transistors (OFETs) through all solution processes on plastic substrate were fabricated. The OFET devices showed low voltage operation and steep subthreshold swing at relatively small gate dielectric capacitance.展开更多
Two-dimensional(2D)organic semiconductor crystals(OSCs)are ideal platforms for investigating fundament materials as well as achieving high-performance organic field-effect transistors(OFETs).The surfactants played an ...Two-dimensional(2D)organic semiconductor crystals(OSCs)are ideal platforms for investigating fundament materials as well as achieving high-performance organic field-effect transistors(OFETs).The surfactants played an important role in the 2DOSCs growth in previous studies.However,residual surfactants may cause performance degradation of devices.Herein,a simple and effective dual-function surfactant strategy is used to control the growth of large-area few-molecular-layer 2DOSCs.The introduction of phosphatidylcholine decreases the interfacial tension and improves the crystal growth dynamics,resulting in high-quality and large-area few-molecular-layer 2,6-bis(4-hexylphenyl)anthracene(C_6–DPA)2DOSC.The additive also passivates charge traps,boosting the mobility of 2DOSC-based OFETs by almost threefold.This method is also suitable for the growth of various high-quality 2DOSCs,opening up a new avenue for high-quality 2DOSCs towards high-performance OFETs.展开更多
We investigated the properties of C_(60)-based organic field-enect transistors(OFETs)(?) a pentacene passivation layer inserted between the C_(60) active layer and the gate dielectric.After modification of th...We investigated the properties of C_(60)-based organic field-enect transistors(OFETs)(?) a pentacene passivation layer inserted between the C_(60) active layer and the gate dielectric.After modification of the pentacene passivation layer,the performance of the devices was considerably improved compared to C_(60)-based OFETs with only a PMMA dielectric.The peak field-effect mobility was up to 1.01 cm^2/(V·s) and the on/off ratio shifted to 10~4.This result indicates that using a pentacene passivation layer is an effective way to improve the performance of N-type OFETs.展开更多
In recent years,organic field-effect transistors(OFETs) with high performance and novel multifunctionalities have attracted considerable attention.Meanwhile,featured with reversible photoisomerization and the corres...In recent years,organic field-effect transistors(OFETs) with high performance and novel multifunctionalities have attracted considerable attention.Meanwhile,featured with reversible photoisomerization and the corresponding variation in color,chemical/physical properties,photochromic molecules have been applied in sensors,photo-switches and memories.Incorporation of photochromic molecules to blend in the device functional layers or to modify the interfaces of OFETs is common way to build photo-transistors.In this review,we focus on the recent advantages on the study of photoresponsive transistors involving one of three typical photochromic compounds spiropyran,diarylethene and azobenzene.Three main strategies are demonstrated in detail.Firstly,photochromic molecules are doped in active layers or combined with semiconductor structure thus forming photoreversible active layers.Secondly,the modification of dielectric layer/active layer interface is mainly carried out by bilayer dielectric.Thirdly,the photo-isomerization of self-assembled monolayer(SAM) on the electrode/active layer interface can reversibly modulate the work functions and charge injection barrier,result in bifunctional OFETs.All in all,the combination of photochromic molecules and OFETs is an efficient way for the fabrication of organic photoelectric devices.Photoresponsive transistors consisted of photochromic molecules are potential candidate for real applications in the future.展开更多
High responsivity and sensitivity play essential roles in the development of organic field-effect transistors(OFETs)-based biosensors with regard to biological detections,particularly for disease diagnosis.Nonetheless...High responsivity and sensitivity play essential roles in the development of organic field-effect transistors(OFETs)-based biosensors with regard to biological detections,particularly for disease diagnosis.Nonetheless,how to design a biosensor which improves these two outstanding properties while achieving low cost,easy processing,and time saving is a daunting challenge.Herein,a novel biosensor based on OFET with copolymer thin film,whose surface is illuminated with a suitable light beam is reported.This film can be used as both an organic semiconductor material and as a photoelectric active material.Due to amplification of signals as a result of the film’s strong response to light,the biosensor possesses higher responsivity and sensitivity compared to dark condition and even realizes a maximum responsivity of up to 10^(3)for alpha-fetoprotein(AFP)detection.The simple combination of light and transistor builds a bridge between photoelectric effect and biological system.In addition,the emergence of more excellent photoelectric active materials is expected to pave a way for ultrasensitive bio-chemical diagnostic tools.展开更多
Introducing photochromic molecules into the active layer of organic field-effect transistors (OFETs) is a direct way to implement a photoresponse nature in OFETs. However, active layer blended photo- responsive tran...Introducing photochromic molecules into the active layer of organic field-effect transistors (OFETs) is a direct way to implement a photoresponse nature in OFETs. However, active layer blended photo- responsive transistors based on n-type semiconductors are challenging and rarely studied, which are crucial for multifunctional organic-based logic applications. Herein, we fabricated n-channel photo- responsive OFETs based on a tri-component active layer spin-coated from the mixed solution of an n-type semiconductor (NDI2OD-DTYM2), spiropyran and polystyrene with a weight ratio of 1:1:1. The morphology of the blended films was improved by the introduction of the polymer matrix. Photochromic spiropyran molecules dispersed in the semiconductor layer could switch between the closed-ring state and ionic open-ring state flexibly under the irradiation of different wavelengths of light, and thus change the channel conductivity reversibly and modulate the OFET characteristics. Therefore, under the irradiation of alternate UV and vis light, both the device carrier mobility and current on and off ratio successfully realized a reversible switch.展开更多
Monolayer organic field-effect transistors(OFETs) are attracting worldwide interest in device physics and novel applications due to their ultrathin active layer for two-dimensional charge transport. The monolayer film...Monolayer organic field-effect transistors(OFETs) are attracting worldwide interest in device physics and novel applications due to their ultrathin active layer for two-dimensional charge transport. The monolayer films are generally prepared by thermal evaporation, the Langmuir technique or self-assembly process, etc., but their electrical performance is relatively lower than corresponding thick films. From 2011, the performance of monolayer OFETs has been boosted by using the monolayer molecular crystals(MMCs) as active channels, which opened up a new era for monolayer OFETs. In this review, recent progress of monolayer OFETs, including the preparation of monolayer films, their OFET performance and applications are summarized.Finally, perspectives of monolayer OFETs in the near future are also discussed.展开更多
Organic field-effect transistors (OFETs) have received significant research interest because of their promising applications in low cast, lager area, plastic circuits, and tremendous progress has been made in material...Organic field-effect transistors (OFETs) have received significant research interest because of their promising applications in low cast, lager area, plastic circuits, and tremendous progress has been made in materials, device performance, OFETs based circuits in recent years. In this article we introduce the advances in organic semiconductor materials, OFETs based integrating techniques, and in particular highlight the recent progress. Finally, the prospects and problems of OFETs are discussed.展开更多
Fused thiophenes refer to oligothienoacenes in which several thiophenes are coupled together via twoor multi-positions and their derivatives. The synthesized organic semiconductors based on fused thiophenes exhibit ex...Fused thiophenes refer to oligothienoacenes in which several thiophenes are coupled together via twoor multi-positions and their derivatives. The synthesized organic semiconductors based on fused thiophenes exhibit excellent field effect properties due to their efficient intermolecular S…S interactions and π…π stacking. The performances of organic field-effect transistors (OFETs) depend not only on the materials but also on the devices. Such factors which influence the device performances as device structures, fabrication technologies and interface engineering are extensively investigated based on the fused thiophenes. Searching for new organic semiconductors and improving the device fabrication technologies are two major issues in the development of OFETs.展开更多
Recent advances in organic electronics of novel materials and optoelectronic devices spark great interest in the design and synthesis of high-performance polymer semiconductors. During the last decade, isoindigo(ⅡD) ...Recent advances in organic electronics of novel materials and optoelectronic devices spark great interest in the design and synthesis of high-performance polymer semiconductors. During the last decade, isoindigo(ⅡD) and its derivatives have sprung up as common electron-deficient building blocks and obtained extensive applications in organic field-effect transistors(OFETs).In this review, we first present the current status, basic principles, and general material design strategies for OFETs. Then,multiple ⅡD-type acceptors, mature synthetic routes to monomers, and typical ⅡDs-based conjugated polymers are summarized.We also introduce side-chain engineering and cutting-edge applications, like stretchable transistors, sensing, active-matrix driving, etc., of the classic copolymer poly(isoindigo-co-bithiophene). Green polymerization approaches towards conjugated polymers incorporating ⅡDs are subsequently discussed for efficient polymerization. Finally, we conclude this review and propose in-depth prospects with respect to material synthesis and device applications. Undoubtedly, ⅡDs-based conjugated polymers would occupy a significant position in the future of organic electronics, due to diverse building blocks, mature synthetic pathways, tunable side chains, and unique optoelectronic properties.展开更多
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financial support from National Key Research and Development Program(Nos.2021YFA0717900,2022YFE0124200)National Natural Science Foundation of China(Nos.62004138,52273190,61905121,U2241221)Haihe Laboratory of Sustainable Chemical Transformations.
文摘The compatibility of the gate dielectrics with semiconductors is vital for constructing efficient conducting channel for high charge transport.However,it is still a highly challenging mission to clearly clarify the relationship between the dielectric layers and the chemical structure of semiconductors,especially vacuum-deposited small molecules.Here,interfacial molecular screening of polyimide(Kapton)dielectric in organic field-effect transistors(OFETs)is comprehensively studied.It is found that the semiconducting small molecules with alkyl side chains prefer to form a high-quality charge transport layer on polyimide(PI)dielectrics compared with the molecules without alkyl side chains.On this basis,the fabricated transistors could reach the mobility of 1.2 cm^(2) V^(−1)s^(−1) the molecule with alkyl side chains on bare PI dielectric.What is more,the compatible semiconductor and dielectric would further produce a low activation energy(E_(A))of 3.01 meV towards efficient charge transport even at low temperature(e.g.,100 K,0.9 cm^(2) V^(−1)s^(−1)).Our research provides a guiding scheme for the construction of high-performance thin-film field-effect transistors based on PI dielectric layer at room and low temperatures.
基金the National Natural Science Foundation of China(grant no.62150610496)Department of Education of Guangdong Province University Innovation Foundation(2021KTSCX107)+2 种基金Shenzhen Science,Technology and Innovation Commission(JCYJ20220530113014033).P.S.is thankful to QUT for the financial support from the Australian Research Council(ARC)for the Discovery Grant(DP210103006)and QUT core funding(QUT/322120-0301/07)The synchrotron radiation experiments were performed at BL40B2 in SPring-8 with the approval of JASRI(Proposal No.2020A0651)The authors thank Dr.Hiroyasu Masunaga and Dr.Noboru Ohta(Japan Synchrotron Radiation Research Institute:JASRI)for assistance in the GIWAXS experiments。
文摘Diketopyrrolopyrrole(DPP)is one of the most promising building blocks for constructing polymer semiconductors with high charge-carrier mobilities in organic field-effect transistors(OFETs).In this study,a novel DPP-based conjugated polymer,PDPPy-BDD,was designed and synthesized.The ambipolar field-effect transistor characteristics were realized with the average hole and electron mobilities of 3.5×10^(-3)and 3.07×10^(-2)cm^(2)V^(-1)s^(-1),respectively.Both the hole and electron mobilities could be successfully en-hanced by using a tetramethylammonium iodide(NMe4l)additive.Such an enhancement was attributed to the formation of stronger interchainπ-πstackings,the weakening of the face-on packing orientation in the thin film state,and the higher channel conductivi-ties in the OFETs.
基金financially supported by the National Key R&D Program of‘Key Scientific Issues of Transformative Technology’(No.2018YFA0703200)the National Natural Science Foundation of China(Nos.U22A6002,91833306,21922511 and 51873216)+4 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB30000000)the CAS Project for Young Scientists in Basic Research(No.YSBR-053)the CAS-Croucher Funding Scheme for Joint Laboratoriesthe CAS Cooperation Project(No.121111KYSB20200036)the Lu Jiaxi international team(No.GJTD-2020-02)。
文摘The recent progress in the design and synthesis of high-performance donor-acceptor conjugated polymeric semiconducting materials is reviewed from the perspective of multiscale structures.The multiscale of conjugated polymers is from the primary one-dimensional polymer molecular scale to the secondary polymer-chains interaction scale,and then to the tertiary polymer aggregate scale.This review focuses on the design and synthesis of polymer molecules,proposes new classification rules,and rationally summarizes the design strategies and modulation methods of polymers.We describe the recent progress from these three aspects:(1)the modification ofπ-conjugated backbone,(2)the evolution of the polymerization methods,and(3)the regulation of aggregate-state structure.
基金supported by the National Natural Science Foundation of China(Nos.22275068,21975178)the Open Project of the State Key Laboratory of Supramolecular Structure and Materials,China.
文摘Biosensors based on organic field-effect transistors(OFETs)are one of the most promising electronic devices for emerging bioanalytical applications.The selection of organic semiconductors(OSCs)is essential to improve the sensitivity and reliability of this kind of biosensors.Given the good field effect performance and tunable structures of D-A type conjugated polymers,here,we design two D-A type copolymers[P(BDT-co-DPP2T-ThC_(2))and P(BDT-co-DPP2T-Th)],which are applied as the OSC layers.With carcinoembryonic antigen antibody(anti-CEA)adsorbed onto the OSC layers as the recognition sites,OFETs based biosensors for CEA detection are developed.The experimental findings support that the attachment of ester side groups onto the polymer backbone[as for P(BDT-co-DPP2T-ThC_(2))]is favorable for improved solubility and filming properties of the polymer.The introduction of ester side groups affects molecular stacking and enhances intermolecular forces.The resultant devices show high charge mobility and antibody adsorption ability,both of which are critical for sensitive and facile detection of CEA biomarkers.The reliable determination of CEA down to the picomolar level is determined.It is expected that this kind of biosensors fabricated by D-A type conducting polymers will open new avenues toward the early diagnosis,real-time monitoring and treatment of future cancer diseases.
文摘The fundamental I-V formula of an organic field effect transistor(OFET)is improved to overcome the divergence of the integrand,so it is very convenient for both numerical calculations and analytic derivations.The analytic I-V formulae are derived based on the exponential mobility model and power-function mobility model,respectively,and the derived analytic formulae are applied to three OFET devices.The results calculated from the reformulated analytic I-V formulae taking in exponential and power function mobility models are all in good agreement with the experimental I-V data.The parameters μ_(0) and γ that are extracted from the mobility model and fitted by experimental data show simple Arrhenius temperature dependence and inverse linear relationship with temperature,respectively.These findings are very useful for practical applications and device simulations.
基金supported by the National Key Research and Development Program of China(Nos.2019YFE0116700 and 2019YFA0705900)Ministry of Science and Technology,National Natural Science Foundation of China(Nos.62075224,22021002,51873182 and 52103231)+3 种基金Zhejiang Province Science and Technology Plan(No.2021C04012)Zhejiang Provincial Department of Science and Technologysupported by the Lu Jiaxi International Teams Project(No.GJTD-2020–02)the Fundamental Research Funds for the Central Universities(No.2021QNA4033)。
文摘Organic field-effect transistors(OFETs)refer to field-effect transistors that use organic semiconductors as channel materials.Owing to the advantages of organic materials such as solution processability and intrinsic flexibility,OFETs are expected to be applicable in emergent technologies including wearable electronics and sensors,flexible displays,internet-of-things,neuromorphic computing,etc.Improving the electrical performance and developing multifunctionalities of OFETs are two major and closely relevant aspects for OFETs-related research.The former one aims for investigating the device physics and expanding the horizons of OFETs,while the later one is critical for leading OFETs into practical and emergent applications.The development in each of the two aspects would undoubtfully promote the other and bring more confidence for future development of OFETs.Hence,this review is divided into two parts that respectively summarize the recent progress in high-performance OFETs and multifunctional OFETs.
基金Project supported by the National Natural Science Foundation of China (Grant No.12065015)the Hongliu Firstlevel Discipline Construction Project of Lanzhou University of Technology。
文摘The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.
文摘1 Restults Tetrathiafulvalene (TTF) and its derivatives have been extensively investigated in the field of organic conductors and superconductors since 1973. Recently, their application in organic field-effect transistors (OFETs) has attracted considerable attention. So far, on the one hand, the fabrication techniques of the TTF-based FETs have been primarily limited to high vacuum evaporation, which is a relatively expensive process. On the other hand, low FET performances, such as the low on/off ratio...
基金financially supported by the National Natural Science Foundation of China (Nos.21674060,21274087,61674102,and 61334008)National Key R&D Program (No.2016YFB0401100)
文摘A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoided. The photo-cross-linker, BBP-4, was added into host polymers by simple solution blending process, which was capable of abstracting hydrogen atoms from polymers containing active C--H groups upon exposure to ultraviolet (UV) radiation. The cross-linking can be completed with a relatively long wavelength UV light (365 nm). The approach has been applied to methacrylate and styrenic polymers such as commercial poly(methylmethacrylate) (PMMA), poly(iso-butylmethacrylate) (PiBMA) and poly(4-methylstyrene) (PMS). The cross-linked networks enhanced dielectric properties and solvent resistance of the thin films. The bottom-gate organic field-effect transistors (OFETs) through all solution processes on plastic substrate were fabricated. The OFET devices showed low voltage operation and steep subthreshold swing at relatively small gate dielectric capacitance.
基金This work was supported by the Ministry of Science and Technology of China(2016YFB0401100,2017YFA0204503,and 2018YFA0703200)the National Natural Science Foundation of China(91833306,51633006,51703159,51733004,51725304,52003189 and 21875158)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12030300)the China Postdoctoral Science Foundation(2020M680875)。
文摘Two-dimensional(2D)organic semiconductor crystals(OSCs)are ideal platforms for investigating fundament materials as well as achieving high-performance organic field-effect transistors(OFETs).The surfactants played an important role in the 2DOSCs growth in previous studies.However,residual surfactants may cause performance degradation of devices.Herein,a simple and effective dual-function surfactant strategy is used to control the growth of large-area few-molecular-layer 2DOSCs.The introduction of phosphatidylcholine decreases the interfacial tension and improves the crystal growth dynamics,resulting in high-quality and large-area few-molecular-layer 2,6-bis(4-hexylphenyl)anthracene(C_6–DPA)2DOSC.The additive also passivates charge traps,boosting the mobility of 2DOSC-based OFETs by almost threefold.This method is also suitable for the growth of various high-quality 2DOSCs,opening up a new avenue for high-quality 2DOSCs towards high-performance OFETs.
基金supported by the National Natural Science Foundation of China(No.61076065)the Natural Science Foundation of Tianjin City,China(No.07JCYBJC12700)
文摘We investigated the properties of C_(60)-based organic field-enect transistors(OFETs)(?) a pentacene passivation layer inserted between the C_(60) active layer and the gate dielectric.After modification of the pentacene passivation layer,the performance of the devices was considerably improved compared to C_(60)-based OFETs with only a PMMA dielectric.The peak field-effect mobility was up to 1.01 cm^2/(V·s) and the on/off ratio shifted to 10~4.This result indicates that using a pentacene passivation layer is an effective way to improve the performance of N-type OFETs.
基金supported financially by the National Natural Science Foundation of China(Nos.21302212 and 21522209)the "Strategic Priority Research Program"(No.XDB12010100)
文摘In recent years,organic field-effect transistors(OFETs) with high performance and novel multifunctionalities have attracted considerable attention.Meanwhile,featured with reversible photoisomerization and the corresponding variation in color,chemical/physical properties,photochromic molecules have been applied in sensors,photo-switches and memories.Incorporation of photochromic molecules to blend in the device functional layers or to modify the interfaces of OFETs is common way to build photo-transistors.In this review,we focus on the recent advantages on the study of photoresponsive transistors involving one of three typical photochromic compounds spiropyran,diarylethene and azobenzene.Three main strategies are demonstrated in detail.Firstly,photochromic molecules are doped in active layers or combined with semiconductor structure thus forming photoreversible active layers.Secondly,the modification of dielectric layer/active layer interface is mainly carried out by bilayer dielectric.Thirdly,the photo-isomerization of self-assembled monolayer(SAM) on the electrode/active layer interface can reversibly modulate the work functions and charge injection barrier,result in bifunctional OFETs.All in all,the combination of photochromic molecules and OFETs is an efficient way for the fabrication of organic photoelectric devices.Photoresponsive transistors consisted of photochromic molecules are potential candidate for real applications in the future.
基金financially supported by the Ministry of Science and Technology of China(Nos.2015CB856502,2016YFB0401100 and 2017YFA0204503)National Natural Science Foundation of China(Nos.21705116,51733004,91433115,51633006,51703160,21661132006,21473222 and 51902131).
文摘High responsivity and sensitivity play essential roles in the development of organic field-effect transistors(OFETs)-based biosensors with regard to biological detections,particularly for disease diagnosis.Nonetheless,how to design a biosensor which improves these two outstanding properties while achieving low cost,easy processing,and time saving is a daunting challenge.Herein,a novel biosensor based on OFET with copolymer thin film,whose surface is illuminated with a suitable light beam is reported.This film can be used as both an organic semiconductor material and as a photoelectric active material.Due to amplification of signals as a result of the film’s strong response to light,the biosensor possesses higher responsivity and sensitivity compared to dark condition and even realizes a maximum responsivity of up to 10^(3)for alpha-fetoprotein(AFP)detection.The simple combination of light and transistor builds a bridge between photoelectric effect and biological system.In addition,the emergence of more excellent photoelectric active materials is expected to pave a way for ultrasensitive bio-chemical diagnostic tools.
基金the National Natural Science Foundation of China (Nos. 21302212 and 21522209)the "Strategic Priority Research Program"(No. XDB12010100) for funding this work
文摘Introducing photochromic molecules into the active layer of organic field-effect transistors (OFETs) is a direct way to implement a photoresponse nature in OFETs. However, active layer blended photo- responsive transistors based on n-type semiconductors are challenging and rarely studied, which are crucial for multifunctional organic-based logic applications. Herein, we fabricated n-channel photo- responsive OFETs based on a tri-component active layer spin-coated from the mixed solution of an n-type semiconductor (NDI2OD-DTYM2), spiropyran and polystyrene with a weight ratio of 1:1:1. The morphology of the blended films was improved by the introduction of the polymer matrix. Photochromic spiropyran molecules dispersed in the semiconductor layer could switch between the closed-ring state and ionic open-ring state flexibly under the irradiation of different wavelengths of light, and thus change the channel conductivity reversibly and modulate the OFET characteristics. Therefore, under the irradiation of alternate UV and vis light, both the device carrier mobility and current on and off ratio successfully realized a reversible switch.
基金supported by the Ministry of Science and Technology of China (2017YFA0204704, 2016YFB0401100)the National Natural Science Foundation of China (21805284, 21873108)the Chinese Academy of Sciences (Hundred Talents Plan and the Strategic Priority Research Program (XDB30000000, XDB12030300)
文摘Monolayer organic field-effect transistors(OFETs) are attracting worldwide interest in device physics and novel applications due to their ultrathin active layer for two-dimensional charge transport. The monolayer films are generally prepared by thermal evaporation, the Langmuir technique or self-assembly process, etc., but their electrical performance is relatively lower than corresponding thick films. From 2011, the performance of monolayer OFETs has been boosted by using the monolayer molecular crystals(MMCs) as active channels, which opened up a new era for monolayer OFETs. In this review, recent progress of monolayer OFETs, including the preparation of monolayer films, their OFET performance and applications are summarized.Finally, perspectives of monolayer OFETs in the near future are also discussed.
基金Supported by the National Basic Research Program of China ("973" Project) (Grant Nos. 2006CB806204, 2009CB939703)the National Natural Science Foundation of China (Grant Nos. 90607022, 60676001, 60676008, 60825403)
文摘Organic field-effect transistors (OFETs) have received significant research interest because of their promising applications in low cast, lager area, plastic circuits, and tremendous progress has been made in materials, device performance, OFETs based circuits in recent years. In this article we introduce the advances in organic semiconductor materials, OFETs based integrating techniques, and in particular highlight the recent progress. Finally, the prospects and problems of OFETs are discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 20825208, 60736004 & 20721061)the National Major State Basic Research Development Program (Grant No. 2006CB806203, 2006CB932103 & 2009CB623603),and the Chinese Academy of Sciences
文摘Fused thiophenes refer to oligothienoacenes in which several thiophenes are coupled together via twoor multi-positions and their derivatives. The synthesized organic semiconductors based on fused thiophenes exhibit excellent field effect properties due to their efficient intermolecular S…S interactions and π…π stacking. The performances of organic field-effect transistors (OFETs) depend not only on the materials but also on the devices. Such factors which influence the device performances as device structures, fabrication technologies and interface engineering are extensively investigated based on the fused thiophenes. Searching for new organic semiconductors and improving the device fabrication technologies are two major issues in the development of OFETs.
基金supported by the National Natural Science Foundation of China (61890940)the National Key R&D Programof “Key Scientific Issues of Transformative Technology” (2018YFA0703200)the CAS-Croucher Funding Scheme for Joint Laboratories and the Chinese Academy of Sciences Research Program (121111KYSB20200036)。
文摘Recent advances in organic electronics of novel materials and optoelectronic devices spark great interest in the design and synthesis of high-performance polymer semiconductors. During the last decade, isoindigo(ⅡD) and its derivatives have sprung up as common electron-deficient building blocks and obtained extensive applications in organic field-effect transistors(OFETs).In this review, we first present the current status, basic principles, and general material design strategies for OFETs. Then,multiple ⅡD-type acceptors, mature synthetic routes to monomers, and typical ⅡDs-based conjugated polymers are summarized.We also introduce side-chain engineering and cutting-edge applications, like stretchable transistors, sensing, active-matrix driving, etc., of the classic copolymer poly(isoindigo-co-bithiophene). Green polymerization approaches towards conjugated polymers incorporating ⅡDs are subsequently discussed for efficient polymerization. Finally, we conclude this review and propose in-depth prospects with respect to material synthesis and device applications. Undoubtedly, ⅡDs-based conjugated polymers would occupy a significant position in the future of organic electronics, due to diverse building blocks, mature synthetic pathways, tunable side chains, and unique optoelectronic properties.