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n‐Type conjugated polymers featuring low‐lying lowest unoccupied molecular orbital (LUMO) energy levels are essential for achieving high‐performance n‐type organic thin‐film transistors (OTFTs) and organic thermoelectrics (OTEs). However, the synthesis of acceptors with strong electron‐withdrawing characteristics presents a significant challenge. Herein, a peripheral functionalization strategy is employed on the tricyclic framework anthracene by introducing dual N,O‐bidentate BF2/B(CN)2 groups to enhance its electron‐withdrawing capability. This approach successfully navigates synthetic challenges, leading to the development of two novel acceptor building blocks: DBNF and DBNCN. Compared to the counterparts with a single N,O‐bidentate BF2/B(CN)2 moiety, DBNF and DBNCN exhibit an extended π‐backbone, enhanced molecular packing, and improved electron‐withdrawing properties. Utilizing these innovative acceptor monomers, copolymers, PDBNF and PDBNCN, are synthesized, which exhibit considerably suppressed LUMO ≈−4.0 eV. The deep LUMO of PDBNF together with its favourable bimodal packing orientation leads to remarkable electron mobility of 3.04 cm2 V−1 s−1 with improved stability in OTFTs. Importantly, efficient n‐doping in OTEs is achieved with PDBNCN, exhibiting exceptional conductivity of 95.5 S cm−1 and a maximum power factor of 147.8 μW m−1 K−2—among the highest reported for solution‐processed n‐type polymers. This work underscores the effectiveness of introducing dual B←N and cyano functionalities in attaining high‐performance n‐type plastic electronics. [ABSTRACT FROM AUTHOR]

In integrated circuits (ICs), the parasitic capacitance is one of the crucial factors that degrade the circuit dynamic performance; for instance, it reduces the operating frequency of the circuit. Eliminating the parasitic capacitance in organic transistors is notoriously challenging due to the inherent tradeoff between manufacturing costs and interlayer alignment accuracy. Here, we overcome such a limitation using a cost‐effective method for fabricating organic thin‐film transistors and rectifying diodes without redundant electrode overlaps. This is achieved by placing all electrodes horizontally and introducing sub‐100 nm gaps for separation. A representative small‐scale IC consisting of five‐stage ring oscillators based on the obtained nonparasitic transistors and diodes is fabricated on flexible substrates, which performs reliably at a low driving voltage of 1 V. Notably, the oscillator exhibits signal propagation delays of 5.8 μs per stage at a supply voltage of 20 V when utilizing pentacene as the active layer. Since parasitic capacitance has been a common challenge for all types of thin‐film transistors, our approach may pave the way toward the realization of flexible and large‐area ICs based on other emerging and highly performing semiconductors. [ABSTRACT FROM AUTHOR]

In recent years, the charge carrier mobility study of organic semiconductors has seen significant progress and surpassed that of amorphous silicon thanks to the development of various molecular engineering, solution processing, and external alignment methods. These advances have allowed the implementation of organic semiconductors for fabricating high-performance organic electronic devices. In particular, diketopyrrolopyrrole-based small-molecular and polymeric organic semiconductors have garnered considerable research interest due to their ambipolar charge-carrier properties. In this article, we focus on conducting a comprehensive review of previous studies that are dedicated to the external alignment, thermal annealing, and molecular engineering of diketopyrrolopyrrole molecular structures and side-chain structures in order to achieve oriented crystal orientation, optimized thin-film morphology, and enhanced charge carrier transport. By discussing these benchmark studies, this work aims to provide general insights into optimizing other high-mobility, solution-processed organic semiconductors and sheds lights on realizing the acceleration of organic electronic device applications. [ABSTRACT FROM AUTHOR]

Conjugated polymers are emerging as competitive candidates for organic thermoelectrics (OTEs). However, to make the device truly pervasive, both p‐ and n‐type conjugated polymers are essential. Despite great efforts, no n‐type equivalents to the p‐type benchmark PEDOT:PSS exist to date mainly due to the low electrical conductivity (σ). Herein, a near‐amorphous n‐type conjugated polymer, namely pDFSe, is reported with high σ by achieving the synergy between charge transport and doping efficiency. The polymer pDFSe is synthesized based on an acceptor‐triad moiety of diketopyrrolopyrrole‐difluorobenzoselenadiazole‐diketopyrrolopyrrole (DFSe), which has the noncovalently‐fused‐ring structure to reinforce the backbone rigidity. Furthermore, an axisymmetric thiophene‐selenophene‐thiophene donor is introduced, which enables the formation of near‐amorphous microstructures. The above merits ensure good doping efficiency without scarifying efficient intrachain charge‐carrier transport. Thus, pDFSe‐based n‐type transistors exhibit high electron mobility up to 6.15 cm2 V−1 s−1, much higher than its reference polymer pDSe without the noncovalently‐fused‐ring structure (0.77 cm2 V−1 s−1). Further upon n‐doping, pDFSe demonstrates excellent σ of 62.6 S cm−1 and maximum power factor of 133.1 μW m−1 K−2, which are among the highest values reported for solution‐processed n‐type polymers. The results demonstrate the great potential of near‐amorphous n‐type conjugated polymers with noncovalently‐fused‐ring structure for the next‐generation OTEs. [ABSTRACT FROM AUTHOR]

Theoretical studies have unequivocally determined the exceptional electron transport properties of the fluorinated tetracyanoquinodimethane (Fx‐TCNQ) family, presenting a promising avenue for the realization of high‐performance n‐channel organic thin‐film transistors (OTFTs). However, owing to the intrinsic low crystallinity of this class of materials, Fx‐TCNQ‐based n‐channel OTFTs have not been experimentally achieved so far. Herein, a molecular step template (MST)‐assisted method that dramatically improves the crystallinity of F4‐TCNQ thin films is reported. The MST not only lowers the nucleation barrier of F4‐TCNQ molecules along the in‐plane direction but also reduces the nucleation density. This approach facilitates the realization of compact, oriented, and highly crystalline F4‐TCNQ thin films, resulting in impressive electron mobility of up to 2.58 cm2 V−1 s−1. Notably, this achievement surpasses the electron mobility of F4‐TCNQ thin films fabricated without the MST by a factor of 107. Furthermore, the incorporation of the p‐type MST provides a novel pathway for constructing complementary inverters, showcasing a high voltage gain of 112.6 V V−1 and a substantial noise margin of 89.3% with exceptional uniformity. In this work, a general and efficient route is paved to produce high‐performance n‐channel OTFTs toward organic complementary circuits. [ABSTRACT FROM AUTHOR]

Abstract In integrated circuits (ICs), the parasitic capacitance is one of the crucial factors that degrade the circuit dynamic performance; for instance, it reduces the operating frequency of the circuit. Eliminating the parasitic capacitance in organic transistors is notoriously challenging due to the inherent tradeoff between manufacturing costs and interlayer alignment accuracy. Here, we overcome such a limitation using a cost‐effective method for fabricating organic thin‐film transistors and rectifying diodes without redundant electrode overlaps. This is achieved by placing all electrodes horizontally and introducing sub‐100 nm gaps for separation. A representative small‐scale IC consisting of five‐stage ring oscillators based on the obtained nonparasitic transistors and diodes is fabricated on flexible substrates, which performs reliably at a low driving voltage of 1 V. Notably, the oscillator exhibits signal propagation delays of 5.8 μs per stage at a supply voltage of 20 V when utilizing pentacene as the active layer. Since parasitic capacitance has been a common challenge for all types of thin‐film transistors, our approach may pave the way toward the realization of flexible and large‐area ICs based on other emerging and highly performing semiconductors.

The choice of deposition technique and post deposition treatment can significantly influence the performance of organic electronic devices by altering the complex relationship between film properties and charge transport. Herein, the influence of deposition method and post deposition thermal annealing on the thin‐film properties of an emerging semiconductor, bis(tri‐n‐propylsilyl oxide) SiPc ((3PS)2‐SiPc), is examined by polarized Raman microscopy. Comparing physical vapor deposition (PVD) and spin‐coating, the orientation of (3PS)2‐SiPc molecules in films is determined and further characterized by X‐ray diffraction to assess variations in microstructure and morphology due to thermal annealing. Despite differences in film formation, non‐annealed organic thin‐film transistors (OTFTs) fabricated by PVD and spin‐coating resulted in similar electron mobilities (μe) on the order of 10−2 cm2 V−1 s−1 and threshold voltages (VT) of 10–20 V. Films fabricated by PVD annealed at 175 °C transition to a new polymorphic form with molecules aligned at a higher angle to the substrate and exhibiting reduced device performance. Conversely, spin‐coated films do not undergo any new polymorph formation or structural reorganization with thermal annealing. PVD fabricated films are thus more readily able to undergo transformations to structure and morphology with post deposition processing, while the microstructure of spin‐coated films is established at the time of deposition. [ABSTRACT FROM AUTHOR]

Advanced neurostimulation systems require intimate interface with brain or peripheral nervous system to provide a therapeutic modulation for patients experiencing neural function loss. To achieve these, it requires stimulators with high‐channel counts and mechanical flexibility. In this invited paper, we showed a 4T1C neurostimulation pixel circuit with an active‐matrix architecture, offering the opportunity for high‐channel counts. In addition, a 4‐mask photolithographic process for highly uniform organic thin‐film transistor (OTFT) integrated system was demonstrated for mechanical flexibility, which shows a high device yield of 100% (50/50) and small device variation in threshold voltage of 0.64 V and in mobility of 4.9%. By implementing OTFTs to this novel neurostimulation architecture, we fabricated an OTFT‐based high‐channel‐count neurostimulation system, showing a high stimulator yield of 71.0% and small variation of 15.6% for the output stimulation currents among pixels. [ABSTRACT FROM AUTHOR]

The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

High‐performing n‐type polymers are crucial for the advance of organic electronics field, however strong electron‐deficient building blocks with optimized physicochemical properties for constructing them are still limited. The imide‐functionalized polycyclic aromatic hydrocarbons (PAHs) with extended π‐conjugated framework, high electron deficiency and good solubility serve as promising candidates for developing high‐performance n‐type polymers. Among the PAHs, phenanthrene (PhA) features a well‐delocalized aromatic π‐system with multiple modifiable active sites. However, the PhA‐based imides are seldom studied, mainly attributed to the synthetic challenge. Herein, we report two functionalized PhAs, CPOI and CPCNI, by simultaneously incorporating imide with carbonyl or dicyanomethylene onto PhA. Notably, the dicyanomethylene‐modified CPCNI exhibits a well stabilized LUMO energy level (−3.84 eV), attributed to the synergetic inductive effect from imide and cyano groups. Subsequently, based on CPOI and CPCNI, two polymers PCPOI‐Tz and PCPCNI‐Tz were developed. Applied to organic thin‐film transistors, owing to the strong electron‐deficiency of CPCNI, polymer PCPCNI‐Tz shows an improved electron mobility and largely decreased threshold voltage compared with PCPOI‐Tz. This work affords two structurally novel electron‐deficient building blocks and highlights the effectiveness of dual functionalization of PhAs with strong electron‐withdrawing groups for devising n‐type polymers. [ABSTRACT FROM AUTHOR]

The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

The lack of ambipolar polymers with balanced hole (μh) and electron mobilities (μe) >10 cm2 V−1 s−1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π‐extended selenium‐containing acceptor‐dimeric unit, namely benzo[c][1,2,5]selenadiazol‐4‐yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur‐counterpart, BBSeE demonstrates enlarged co‐planarity, selective noncovalent interactions, polarized Se−N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor‐acceptor copolymer pN‐BBSeE, which shows a narrower band gap, lower‐lying lowest unoccupied molecular orbital level (−4.05 eV), and a higher degree of backbone planarity. Consequently, the pN‐BBSeE‐based organic transistors display an ideally balanced ambipolar transporting property with μh and μe of 10.65 and 10.72 cm2 V−1 s−1, respectively. To the best of our knowledge, the simultaneous μh/μe values >10.0 cm2 V−1 s−1 are the best performances ever reported for ambipolar polymers. In addition, pN‐BBSeE shows an excellent shelf‐storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π‐extended acceptor‐dimeric BBSeE is a promising acceptor building block for constructing high‐performance ambipolar polymers applied in next‐generation organic integrated circuit. [ABSTRACT FROM AUTHOR]

Abstract With the rapid development of advanced technologies in the Internet of Things era, higher requirements are needed for next‐generation electronic devices. Fortunately, organic thin film transistors (OTFTs) provide an effective solution for electronic skin and flexible wearable devices due to their intrinsic features of mechanical flexibility, lightweight, simple fabrication process, and good biocompatibility. So far considerable efforts have been devoted to this research field. This article reviews recent advances in various promising and state‐of‐the‐art OTFTs as well as related integrated circuits with the main focuses on: (I) material categories of high‐mobility organic semiconductors for both individual transistors and integrated circuits; (II) effective device architectures and processing techniques for large‐area fabrication; (III) important performance metrics of organic integrated circuits and realization of digital and analog devices for future smart life; (IV) applicable analytical models and design flow to accelerate the circuit design. In addition, the emerging challenges of OTFT‐based integrated circuits, such as transistor uniformity and stability are also discussed, and the possible methods to solve these problems at both transistor and circuit levels are summarized.

Theoretical studies have unequivocally determined the exceptional electron transport properties of the fluorinated tetracyanoquinodimethane (Fx‐TCNQ) family, presenting a promising avenue for the realization of high‐performance n‐channel organic thin‐film transistors (OTFTs). However, owing to the intrinsic low crystallinity of this class of materials, Fx‐TCNQ‐based n‐channel OTFTs have not been experimentally achieved so far. Herein, a molecular step template (MST)‐assisted method that dramatically improves the crystallinity of F4‐TCNQ thin films is reported. The MST not only lowers the nucleation barrier of F4‐TCNQ molecules along the in‐plane direction but also reduces the nucleation density. This approach facilitates the realization of compact, oriented, and highly crystalline F4‐TCNQ thin films, resulting in impressive electron mobility of up to 2.58 cm2 V−1 s−1. Notably, this achievement surpasses the electron mobility of F4‐TCNQ thin films fabricated without the MST by a factor of 107. Furthermore, the incorporation of the p‐type MST provides a novel pathway for constructing complementary inverters, showcasing a high voltage gain of 112.6 V V−1 and a substantial noise margin of 89.3% with exceptional uniformity. In this work, a general and efficient route is paved to produce high‐performance n‐channel OTFTs toward organic complementary circuits.

The early determination of disease-related biomarkers can significantly improve the survival rate of patients. Thus, a series of explorations for new diagnosis technologies, such as optical and electrochemical methods, have been devoted to life and health monitoring. Organic thin-film transistor (OTFT), as a state-of-the-art nano-sensing technology, has attracted significant attention from construction to application owing to the merits of being label-free, low-cost, facial, and rapid detection with multi-parameter responses. Nevertheless, interference from non-specific adsorption is inevitable in complex biological samples such as body liquid and exhaled gas, so the reliability and accuracy of the biosensor need to be further improved while ensuring sensitivity, selectivity, and stability. Herein, we overviewed the composition, mechanism, and construction strategies of OTFTs for the practical determination of disease-related biomarkers in both body fluids and exhaled gas. The results show that the realization of bio-inspired applications will come true with the rapid development of high-effective OTFTs and related devices. [ABSTRACT FROM AUTHOR]

With growing interest in organic phototransistors, as not only sensors but also neuromorphic computing elements, the vast majority of research investigates structures comprising Ohmic source/drain contacts. Here, it is shown how source‐gated transistors (SGTs), in which a source contact barrier dominates electrical characteristics, can be implemented as phototransistors. Organic photo‐SGTs (OPSGTs) based on vacuum‐processed small‐molecule dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐]thiophene (DNTT) demonstrate low saturation voltage, exceptional tolerance to channel length variation, and photo‐to‐dark current ratio (PDCR) peaks over 106 for 819 µW broad spectrum incident light power. At zero gate‐source voltage, the PDCR reaches 104, showing promise for simple sensor circuit implementation in medical and wellbeing applications. [ABSTRACT FROM AUTHOR]

A series of thienoisoindigo (TIG)‐based conjugated polymers (CPs) with high molecular weights are synthesized by direct arylation polycondensation (DArP) by using TIG derivatives as CBr monomer and multi‐halogenated thiophene derivatives, i.e., (E)–1,2‐bis(3,4‐difluorothien‐2‐yl)ethene (4FTVT), (E)–1,2‐bis(3,4‐dichlorothien‐2‐yl)ethene (4ClTVT), 3,3',4,4'‐tetrafluoro‐2,2'‐bithiophene (4FBT), and 3,3',4,4'‐tetrachloro‐2,2'‐bithiophene (4ClBT), as CH monomers. Density functional theory (DFT) calculations reveal the high selectivity between α‐CH bonds in 4FTVT, 4ClTVT, 4FBT, and 4ClBT and β‐CH bonds in TIG CBr monomer. All four resulting CPs exhibit low optical bandgaps of ca. 1.20 eV and ambipolar transport characteristics with both electron and hole mobility above 0.1 cm2 V−1 s−1 as elaborated with organic thin‐film transistors (OTFTs). The polymer TIG‐4FTVT delivers the best device performance. With this polymer, n‐channel OTFTs with electron mobility up to 1.67 cm2 V−1 s−1 and p‐channel OTFTs with hole mobility up to 0.62 cm2 V−1 s−1 are fabricated by modifying source/drain electrodes with polyethylenimine ethoxylated (PEIE) and MoO3, respectively, to selectively inject electrons and holes. [ABSTRACT FROM AUTHOR]

Mobility is an important parameter to estimate the performance of organic thin‐film transistors, one of the key factors affecting the mobility is the first several semiconductors molecular layers near the insulator surface. A strategy is proposed to introduce aromatic‐rings in the gate insulating layer to modulate the growth of pentacene, thus a series of aryl group containing polymers by reversible‐addition‐fragmentation chain‐transfer polymerization is synthesized for the preparation of organic thin‐film transistor insulators. The semiconductor layer is evaporated on the polymer insulators at room temperature. As the inducing function of the aromatic ring, greater weak interactions between dielectric materials and semiconductors by simulation, which makes the initial pentacene layer weak epitaxial growth, therefore pentacene could form better morphology, especially larger crystal domains and uniform thin‐film continuity. The results show that precision design and synthesis of polymer insulator layers provide new methods to achieve high performance of organic thin‐film transistors with easier fabricating process. [ABSTRACT FROM AUTHOR]

The choice of deposition technique and post deposition treatment can significantly influence the performance of organic electronic devices by altering the complex relationship between film properties and charge transport. Herein, the influence of deposition method and post deposition thermal annealing on the thin‐film properties of an emerging semiconductor, bis(tri‐n‐propylsilyl oxide) SiPc ((3PS)2‐SiPc), is examined by polarized Raman microscopy. Comparing physical vapor deposition (PVD) and spin‐coating, the orientation of (3PS)2‐SiPc molecules in films is determined and further characterized by X‐ray diffraction to assess variations in microstructure and morphology due to thermal annealing. Despite differences in film formation, non‐annealed organic thin‐film transistors (OTFTs) fabricated by PVD and spin‐coating resulted in similar electron mobilities (μe) on the order of 10−2 cm2 V−1 s−1 and threshold voltages (VT) of 10–20 V. Films fabricated by PVD annealed at 175 °C transition to a new polymorphic form with molecules aligned at a higher angle to the substrate and exhibiting reduced device performance. Conversely, spin‐coated films do not undergo any new polymorph formation or structural reorganization with thermal annealing. PVD fabricated films are thus more readily able to undergo transformations to structure and morphology with post deposition processing, while the microstructure of spin‐coated films is established at the time of deposition.

Driven by the success of quinoidal units for enabling high‐performance polymer semiconductors, herein a new quinoidal building block that terminated by indandione is reported. By introducing Br atoms into the terminal benzene rings of indandione, two CPs, P2TbTI‐DPP and P2TbTI‐TIID, are synthesized through Stille polycondensation. The strong electron‐withdrawing ability of indandione‐terminated quinoidal unit enables P2TbTI‐DPP and P2TbTI‐TIID with low‐lying LUMO energy levels of ≈–3.90 eV. Organic thin‐film transistors based on P2TbTI‐DPP and P2TbTI‐TIID exhibit n‐type transport behavior. Besides, it is found that the electron mobility of these two polymers is weakly dependent on the annealing temperature due to the near‐amorphous of polymer thin‐film. [ABSTRACT FROM AUTHOR]

3,4‐Difluorothiophene‐substituted aryls, i.e., 1,4‐bis(3,4‐difluorothiophen‐2‐yl)‐benzene (Ph‐2FTh), 1,4‐bis(3,4‐difluorothiophen‐2‐yl)‐2,5‐difluorobenzene (2FPh‐2FTh), and 4,7‐bis(3,4‐difluorothiophen‐2‐yl)‐2,1,3‐benzothiadiazole (BTz‐2FTh), are synthesized as C─H monomers for the synthesis of conjugated polymers (CPs) via direct arylation polycondensation (DArP) with diketopyrrolopyrrole (DPP) and isoindigo (IID) derivatives as C─Br monomers. The Gibbs free energies of activation for direct arylation (ΔG298 K, kcal mol−1) for α─C─H bonds of thiophene moieties as calculated by density functional theory (DFT) are 14.3, 16.5, and 16.4 kcal mol−1 for Ph‐2FTh, 2FPh‐2FTh and BTz‐2FTh, respectively, meaning that inserting an electron‐deficient unit in 3,3′,4,4′‐tetrafluoro‐2,2′‐bithiophene (4FBT, ΔG298K: 14.6 kcal mol−1) may cause a reactivity decrease of the C─H monomers. Photophysical and semiconducting properties of the resulting six CPs (i.e., DPP‐Ph, DPP‐2FPh, DPP‐BTz, 2FIID‐Ph, 2FIID‐2FPh, and 2FIID‐BTz) are characterized in detail. DPP‐based CPs show ambipolar transport properties while IID‐based ones exhibited n‐type behavior owing to the deeper frontier molecular orbital energy levels of IID‐based CPs. With source/drain electrodes modified with polyethylenimine ethoxylated, n‐channel organic thin‐film transistors with maximum electron mobility of 0.40, 0.54, 0.29, 0.05, 0.16, and 0.01 cm2 V−1 s−1 for DPP‐Ph, DPP‐2FPh, DPP‐BTz, 2FIID‐Ph, 2FIID‐2FPh, and 2FIID‐BTz, respectively, are fabricated. DPP‐2FPh exhibits the best device performance due to the good film morphology and the highest intermolecular packing order. [ABSTRACT FROM AUTHOR]

Here, a polymer blend active layer that exhibits both electronic and adhesive properties is introduced. Various conjugated polymers are blended with a catechol‐based polymer that shows high adhesion, such that blends serve as the active layer of multifunctional sticky organic thin‐film transistors (OTFTs). Blend films maintain relatively constant field‐effect charge carrier mobility in OTFTs regardless of composition. Lap shear adhesion strength tests show that all blend films exhibit adhesive properties with adhesion values ranging from 0.05 to 4.30 MPa. With relatively consistent mobility and the presence of adhesive properties at different compositions, blends of conjugated and adhesive polymers can lead to next‐generation organic transistors for stable 3D stacking and waterproof adhesive sensors. [ABSTRACT FROM AUTHOR]

Integration of organic thin‐film transistor (OTFT) devices with a wireless data transmission system such as 2.4‐GHz Bluetooth low energy (BLE) is a significant requirement for activating the Internet of Thing (IoT) ecosystem based on a vast number of sensors, while conventional OTFT circuits have problems with their high output impedance and the need for multiple power supplies. Here, a wireless, real‐time, and flexible sodium ion sensing system composed of a printed Na+ sensor, printed OTFT‐based amplifiers, inorganic passive elements, a BLE module, and a 3‐V sheet‐type battery is demonstrated. The printed organic amplifier circuits based on dual threshold technology and dual‐gate structure are combinable with a BLE module because of their low output impedance of 50 kΩ and operate with 3‐V single supply as well as improving operational stability under illumination. The sensitivity to Na+ concentration is improved from 53.7 to 242.5 mV dec−1 (4.5 times higher) by the OTFT‐based amplifier, and the data is transmitted in real‐time to a tablet via the BLE wireless communication. [ABSTRACT FROM AUTHOR]

Abstract Here, a polymer blend active layer that exhibits both electronic and adhesive properties is introduced. Various conjugated polymers are blended with a catechol‐based polymer that shows high adhesion, such that blends serve as the active layer of multifunctional sticky organic thin‐film transistors (OTFTs). Blend films maintain relatively constant field‐effect charge carrier mobility in OTFTs regardless of composition. Lap shear adhesion strength tests show that all blend films exhibit adhesive properties with adhesion values ranging from 0.05 to 4.30 MPa. With relatively consistent mobility and the presence of adhesive properties at different compositions, blends of conjugated and adhesive polymers can lead to next‐generation organic transistors for stable 3D stacking and waterproof adhesive sensors.

Abstract Integration of organic thin‐film transistor (OTFT) devices with a wireless data transmission system such as 2.4‐GHz Bluetooth low energy (BLE) is a significant requirement for activating the Internet of Thing (IoT) ecosystem based on a vast number of sensors, while conventional OTFT circuits have problems with their high output impedance and the need for multiple power supplies. Here, a wireless, real‐time, and flexible sodium ion sensing system composed of a printed Na+ sensor, printed OTFT‐based amplifiers, inorganic passive elements, a BLE module, and a 3‐V sheet‐type battery is demonstrated. The printed organic amplifier circuits based on dual threshold technology and dual‐gate structure are combinable with a BLE module because of their low output impedance of 50 kΩ and operate with 3‐V single supply as well as improving operational stability under illumination. The sensitivity to Na+ concentration is improved from 53.7 to 242.5 mV dec−1 (4.5 times higher) by the OTFT‐based amplifier, and the data is transmitted in real‐time to a tablet via the BLE wireless communication.

Developing high‐performance but low‐cost n‐type polymers remains a significant challenge in the commercialization of organic field‐effect transistors (OFETs). To achieve this objective, it is essential to design the key electron‐deficient units with simple structures and facile preparation processes, which can facilitate the production of low‐cost n‐type polymers. Herein, by sequentially introducing fluorine and cyano functionalities onto trans‐1,3‐butadiene, we developed a series of structurally simple but highly electron‐deficient building blocks, namely 1,4‐dicyano‐butadiene (CNDE), 3‐fluoro‐1,4‐dicyano‐butadiene (CNFDE), and 2,3‐difluoro‐1,4‐dicyano‐butadiene (CNDFDE), featuring a highly coplanar backbone and deep‐positioned lowest unoccupied molecular orbital (LUMO) energy levels (−3.03–4.33 eV), which render them highly attractive for developing n‐type semiconducting polymers. Notably, all these electron‐deficient units can be easily accessed by a two‐step high‐yield synthetic procedure from low‐cost raw materials, thus rendering them highly promising candidates for commercial applications. Upon polymerization with diketopyrrolopyrrole (DPP), three copolymers were developed that demonstrated unipolar n‐type transport characteristics in OFETs with the highest electron mobility of >1 cm2 V−1 s−1. Hence, CNDE, CNFDE, and CNDFDE represent a class of novel, simple, and efficient electron‐deficient units for constructing low‐cost n‐type polymers, thereby providing valuable insight for OFET applications. [ABSTRACT FROM AUTHOR]

Detecting volatile organic compounds is a fundamental step in water quality analysis. Methylisoborneol (MIB) provides a lousy odor to water, whereas geosmin (GEO) is responsible for its sour taste. A widely-used technique for their detection is gas-phase chromatography. On the other hand, an electronic nose from organic thin-film transistors is a cheaper and faster alternative. Poly(2,5-bis(3-tetradecyl-thiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT-C14) features semiconducting properties suitable for organic electronics. However, in order to expose the active layer in a bottom-gate transistor structure with photolithographically patterned electrodes, a cross-linked dielectric such as poly(4-vinyl phenol) (PVP) is necessary. In this work, the cross-linking was demonstrated using FTIR and Raman spectroscopies, as well as high-k capacitors with a dielectric constant of 5.3 . The presence of enhanced crystallinity with terrace formation in the semiconducting film was confirmed with UV-visible spectrophotometry, atomic force microscopy, and X-ray diffraction. Finally, for the first time, a PBTTT-C14 transistor on cross-linked PVP was shown to respond to isoborneol with a sensitivity of up to 6% change in mobility per ppm. Due to its similarity to MIB, a system comprising these sensors must be investigated in the future as a tool for sanitation companies in real-time water quality monitoring. [ABSTRACT FROM AUTHOR]

Thienoacenes are a representative class of high mobility organic semiconductor materials (OSCs). Asymmetric molecules based on them tend to form a bilayer arrangement in thin films and grow in a twodimensional layer-like manner, which has the advantage of achieving high mobility. The length of the alkyl substituents affects the packing microstructure of OSCs. Herein, thieno [4, 5-b] [1] benzothieno [3, 2-b] [1] benzothiophenes substituted with different lengths of alkyl chains (syn-BTBTT-Cn, n=4, 5, 6, 7, 8, 10) are designed and synthesized to systematically investigate the effects of lengths of alkyl chains on their thermal stability, energy levels, charge carrier transport capabilities, packing structures and film morphologies. All compounds are thermally stable and do not have liquid crystalline behaviors. All molecules in the vacuumdeposited films form a bilayer arrangement, within the conjugated cores forming a herringbone packing motif, and the alkyl chain length affects the film order and the tightness of the packing. Organic thin. film transistors devices all exhibit mobilities beyond 7. 0 cm² (/ V·s). Among them, the syn-BTBTT-C8 devices show a mobility of up to 13. 8 cm² (/ V·s) with the average values of 12. 5 cm² (/ V·s). [ABSTRACT FROM AUTHOR]

This invited paper reviews the development of all‐inkjet‐printed organic thin‐film transistors and their applications to wearable bioelectronics, for which ultra‐low power, high gain and stretchability are important characteristics. The subthreshold operation of devices is discussed, and a structure for transparent devices is demonstrated. [ABSTRACT FROM AUTHOR]

The solubility of a direct arylation polycondensation (DArP) synthesized conjugated polymer, i.e., poly(3,6-bis(furan-2-yl)-2,5-bis(4-tetradecyloctadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-1,2-bis(3,4-difluorothien-2-yl)ethene) (PFuDPP-4FTVT), in various organic solvents was studied. The polymer is soluble in 3-methylcyclohexanone (3-MC), a green solvent from peppermint oil, besides other solvents such as anisole, cyclopentyl methyl ether (CPME) and o-dichlorobenzene (o-DCB), etc. Based on the Hansen solubility parameters (HSP) analysis, 3-MC is identified as a "marginal solvent" of PFuDPP-4FTVT. The morphology of the spin-coated films with 3-MC as the solvent strongly correlated with the solution preparation conditions. With a 3-MC solution aged for 3 h at 70 °C, n-channel organic thin-film transistors (OTFTs) with electron mobility (μe) above 1 cm2·V−1·s−1 and current on/off ratio (Ion/Ioff) higher than 105 were fabricated by spin-coating. This is the first report on high mobility conjugated polymers for OTFTs processible with naturally occurred green solvent. [ABSTRACT FROM AUTHOR]

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In this study, organic thin‐film transistors (OTFTs) are investigated as a promising platform for cost‐effective, reconfigurable, and strong electronic physically unclonable functions (PUFs) for highly secure cryptography primitives. Simple spin‐casting of solution‐processable small‐molecule organic semiconductors forms unique and unclonable fingerprint thin films with randomly distributed polycrystalline structures ranging from nanoscale molecular orientations to microcrystalline orientations, which provides a stochastic entropy source of device‐to‐device variations for OTFT arrays. Blending organic semiconductors with polymer materials is a promising strategy to improve the reliability of OTFT‐based PUFs. Studies on the relationship between the phase‐separated polycrystalline microstructure of organic semiconductor/polymer blend films and PUF characteristics reveal that the 2D mosaic microcrystalline structure of organic semiconductors in the vertically phase‐separated trilayered structure enables the implementation of OTFT‐based PUFs that simultaneously satisfy the requirements of being unclonable and unpredictable, with reliable cryptographic properties. The inherent multiscale randomness of the crystalline structure allows random distribution in OTFT‐based PUFs even with various channel dimensions. The secret bit stream generated from the OTFT‐based PUF developed in this study is reconfigurable by simply changing the gate bias, demonstrating the potential to counter evolving security attack threats. [ABSTRACT FROM AUTHOR]

Quinoidal compounds have great potential utility as high‐performance organic semiconducting materials because of their rigid planar structures and extended π‐conjugation. However, the existence of E and Z isomers adversely affects the charge‐transport properties of quinoidal compounds. In this study, three isomerically pure oxindole‐terminated quinoids were developed by introducing chlorine atoms in the quinoidal core. The synthesized quinoids were confirmed to have a Z,Z configuration by means of 1H NMR spectroscopy, density functional theory calculations, and single‐crystal X‐ray analysis. Importantly, the strategy of chlorination allowed to maintain low‐lying frontier molecular orbital energy levels and ensure favorable intermolecular packing. Consequently, all three quinoidal compounds showed n‐type transport characteristics in organic thin‐film transistors, with electron mobilities up to 0.35 cm2 V−1 s−1, which is the highest value reported to date for oxindole‐terminated quinoids. Our study can provide new guidelines for the design of isomerically pure quinoids with high electron mobilities. [ABSTRACT FROM AUTHOR]

Organic semiconductors are excellent candidates for X‐ray detectors that can adapt to new applications, with unique properties including mechanical flexibility and the ability to cover large surfaces. Their chemical composition, primarily carbon and hydrogen, makes them human tissue equivalent in terms of radiation absorption. This is a highly desirable property for a radiation dosimeter to be employed in medical diagnostics and therapy, however a low‐Z composition limits the absorption of ionizing radiation. The detection efficiency can be enhanced by considering the photoconductive gain (PG) effect, a significant contributor to the ionizing radiation detection mechanism in this class of materials. In this work, a process of controlled solution deposition by nozzle printing and crystallization of an organic semiconductor thin film is demonstrated whereby a flexible, arrayed thin‐film X‐ray detector with record X‐ray sensitivities among flexible radiation detectors (S = (9.0 ± 0.4) × 107 µC Gy−1 cm−3) is developed. The excitonic peaks responsible for the activation of the PG effect are investigated and identified using a novel technique called photocurrent spectroscopy optical quenching, and the analysis of the changes in trap states is further demonstrated. [ABSTRACT FROM AUTHOR]

The development of readily accessible high-mobility n-type semiconducting polymers is in great demand for realizing high-performance p-n junction-based organic electronics. In this study, we demonstrate that with the combination of dual-acceptor strategy and C-H direct arylation polymerization (DArP), unipolar n-type semiconducting polymers can be conveniently synthesized. By tuning the monomer concentration, three dual-acceptor polymers, namely, poly(naphthalene diimide-alt-dithiophenyl pyrrolopyrrole-dione) (PNDI-DPP), poly(naphthalene diimide-alt-dithiophenyl isoindigo) (PNDI-IID), and poly (naphthalene diimide-alt-dithiophenyl bezothiadiazole) (PNDI-BT) can be obtained via C-H activation with decent number average molecular weight of ∼10 to 30 kg mol−1 and relatively narrow polydispersity index of ∼2. In addition, these polymers are defect-free in nature as evidenced by the nuclear magnetic resonance. Moreover, we attribute the different molar masses of the three copolymers under the same DArP condition to the different α-C-H acidity, which may stem from different electron-withdrawing capability of the hydrogenated acceptor units. Furthermore, the influence of the hydrogenated acceptor monomers on the optical, electrochemical and charge transporting properties is comprehensively studied. Among the three dual-acceptor polymers, PNDI-BT demonstrates the highest electron mobilities of up to 0.6 cm2 V−1 s−1 in unipolar n-type organic transistors because of its relatively planar backbone, larger overlaps of the lowest unoccupied molecular orbital and strong H-aggregation. Note that the transistor performance of PNDI-BT synthesized via C-H activation in this study is at least comparable to the one made by conventional C(sp2)-C(sp2) Stille or Suzuki cross-coupling polymerization. This study demonstrates the presented protocol can be a useful platform for sustainable and convenient synthesis of high-performance n-type semiconducting polymers. [ABSTRACT FROM AUTHOR]

In the present work synthesis of new semiconductor-based Schiff's base Cu/Zn-complexes for sonophoto mineralization of agrichemical wastewater (ACWW), pesticides, and various types of industrial wastewater, are reported under ultrasonicated and visible light treatment circumstances. The newly prepared ligands and [Cu 2 (HBAPAT)(OAc) 2 ] and [Zn 2 (HBAPAT)(OAc) 2 ] complexes are systematically analyzed with several spectroscopic methods and confirmed as 2:1 ratio of Cu2+/Zn2+ ions and ligand with distorted octahedral structure. These reported complexes are used for the sonophoto mineralization of ACWW and pesticides under ultrasonication and visible light treatment. With the increase in the dosage of complexes, the rate of mineralization of ACWW increased. Further, ACWW samples were analyzed through HPLC and mass spectral techniques for identification of various pesticides present in wastewater samples, before and after sonophotocatalysis. The active species for sonophotocatalysis of ACWW were identified by EPR, scavengers for superoxide radicals and metal organic thin-film transistor study for electrons. The metal complex [Cu 2 (HBAPAT)(OAc) 2 ] is with better efficiency than [Zn 2 (HBAPAT)(OAc) 2 ] for mineralization of ACWW and pesticides are reported using indigenous sonophotocatalytic reactor. [Display omitted] • Synthesis and characterization of new semiconductor-based bis Cu/Zn (II) complexes. • Cu(II) complex shows higher sonophotomineralization of ACWW, pesticides and IWW. • ACWW sonophotocatalyzed samples analyzed with HPLC and MS techniques. • Sonophotocatalysis mechanism of ACWW by Cu(II) complex was systematically studied. [ABSTRACT FROM AUTHOR]

Field-effect gas sensors, integrating the gas sensor and amplification transistor, exhibit excellent sensory performance. Here we report organic thin-film transistors (OTFTs) with nanofiber-textured semiconductor films that exhibit superior ammonia response compared to conventional OTFTs with uniform/flat semiconductor films. The introduce of insulating polymer additives (IPAs) facilitates the formation of semiconducting nanofiber during coating. The effects of IPAs, organic semiconductor/IPA blend ratios and solvents on OTFT-based sensory performance are studied. The results show that the use of SU8 as IPA and chloroform as solvent form intertwined semiconductor nanofibers (∼50 nm in diameter) at the bottom. The resulting OTFTs exhibit extraordinarily high sensitivities to ammonia, which reach 13676%/ppm (current) and 457%/ppm (turn-on voltage), respectively. Finite element analysis is conducted to simulate the adsorption/desorption processes of gas molecules and the effect of specific surface area on sensory performance.

Two novel asymmetric silicon phthalocyanine (SiPc) derivatives consisting of one axially substituted fluorine and one tri‐alkyl silane group are synthesized and characterized in n‐type solution processed bottom‐gate top‐contact organic thin‐film transistors (OTFTs). The effect of surface energy and fluorination are investigated at the dielectric/semiconductor interface by thin‐film X‐ray diffraction, atomic force microscopy, bright field real‐color microscopy, and grazing‐incidence wide‐angle X‐ray scattering to assess alterations in film conformation, microstructure, and morphology. Low surface energy dielectric modification and the presence of fluorine interactions produce films with large area crystalline domains that promote charge carrier transport resulting in high performing OTFTs, with a clear relationship determined between surface energy, fluorination, and OTFT operation. Through modifying deposition solvent and the exploitation of fluorine–fluorine interactions, the asymmetric SiPc derivative, (tri‐n‐hexylsilyl oxide) fluorosilicon phthalocyanine (F‐3HS‐SiPc), leads to high performing n‐type OTFTs with an average field‐effect mobility of 0.13 cm2 V−1 s−1 and a threshold voltage of 26.3 V. These results successfully demonstrate the use of asymmetric axial fluorination as a route to high performance n‐type OTFT devices through controlled self‐assembly by fluorine–fluorine interactions. [ABSTRACT FROM AUTHOR]

Recent studies in solution processed, small molecular organic semiconductors have reported unparalleled advances in charge carrier mobilities, warranting promising application in organic electronic devices such as organic gas sensors and complimentary circuits. However, the in-solution crystallization of small molecular organic semiconductors has presented specific challenges including crystal misorientation, grain boundary and mobility variation. In this article, we first discuss the effects of these issues on charge transport and highlight the virtues of solvent choices to optimize the semiconductor morphology. Then, we conduct an in-depth review of the miscellaneous solvent exchange methods to effectively palliate these challenges. By discussing various benchmark semiconductor materials such as 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) and perylenetetracarboxyldiimide derivatives (PTCDI-Cn), we demonstrate the solvent exchange-based crystallization methods can modulate supramolecular aggregation, promote nucleation formation, improve semiconductor alignment, change crystal dimensionality, and enhance charge transport. We believe this work provides useful comprehension of employing the solvent exchange methods to powerfully regulate the crystallization, morphology and mobility of organic semiconductors, and thereby casts light on high performance organic electronic applications. [ABSTRACT FROM AUTHOR]

The significant contact resistance at the metal-semiconductor interface is a well-documented issue for organic thin-film transistors (OTFTs) that hinders device and circuit performance. Here, this issue is tackled by developing three new thiol carbazole-based self-assembled monolayer (SAM) molecules, namely tBu-2SCz, 2SCz, and Br-2SCz, and utilizing them as carrier-selective injection interlayers. The SAMs alter the work function of gold electrodes by more than 1 eV, making them suitable for use in hole and electron-transporting OTFTs. Scanning tunneling microscopy analysis indicates that 2SCz and Br-2SCz form highly ordered molecular rows, resulting in work function values of 4.86 and 5.48 eV, respectively. The latter value is higher than gold electrodes modified by the commonly used pentafluorobenzenethiol (≈5.33 eV), making Br-2SCz promising for hole injection. Conversely, tBu-2SCz appears disordered with a lower work function of 4.52 eV, making it more suitable for electron injection. These intriguing properties are leveraged to demonstrate hole- and electron-transporting OTFTs with improved operating characteristics. All-organic complementary inverters are finally demonstrated by integrating p- and n-channel OTFTs, showcasing the potential of this simple yet powerful contact work function engineering approach. The present study highlights the versatility of thiol carbazole SAMs as carrier injecting interlayers for OTFTs and integrated circuits., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Detecting volatile organic compounds is a fundamental step in water quality analysis. Methylisoborneol (MIB) provides a lousy odor to water, whereas geosmin (GEO) is responsible for its sour taste. A widely-used technique for their detection is gas-phase chromatography. On the other hand, an electronic nose from organic thin-film transistors is a cheaper and faster alternative. Poly(2,5-bis(3-tetradecyl-thiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT-C14) features semiconducting properties suitable for organic electronics. However, in order to expose the active layer in a bottom-gate transistor structure with photolithographically patterned electrodes, a cross-linked dielectric such as poly(4-vinyl phenol) (PVP) is necessary. In this work, the cross-linking was demonstrated using FTIR and Raman spectroscopies, as well as high-k capacitors with a dielectric constant of 5.3. The presence of enhanced crystallinity with terrace formation in the semiconducting film was confirmed with UV-visible spectrophotometry, atomic force microscopy, and X-ray diffraction. Finally, for the first time, a PBTTT-C14 transistor on cross-linked PVP was shown to respond to isoborneol with a sensitivity of up to 6% change in mobility per ppm. Due to its similarity to MIB, a system comprising these sensors must be investigated in the future as a tool for sanitation companies in real-time water quality monitoring.

We present a comprehensive numerical analysis of contact resistance in coplanar organic thin-film transistors. A large number of hole-transporting organic transistors are investigated through two-dimensional finite-element simulation, by deliberately changing the channel length, source/drain electrode thickness, and hole-injection energy barrier heights. Gate-field-dependent terminal contact resistances of these devices are fully estimated and electrostatic distributions inside the organic semiconductor film are visualized for the understanding of physical mechanisms. It is found that the relationship between source/drain electrode thickness and contact resistance does not follow any simple trend and is also strongly associated with the injection energy barrier. Moreover, the origin of negative contact resistance in organic transistors featuring a minimal charge-injection barrier is elaborated. Finally, a direct impact of the semiconductor charge-carrier mobility on contact resistance is addressed, revealing a linear dependence of contact resistance on inverse mobility over a broad parameter range. [ABSTRACT FROM AUTHOR]

The high‐frequency and low‐voltage operation of organic thin‐film transistors (OTFTs) is a key requirement for the commercial success of flexible electronics. Significant progress has been achieved in this regard by several research groups highlighting the potential of OTFTs to operate at several tens or even above 100 MHz. However, technology maturity, including scalability, integrability, and device reliability, is another crucial point for the semiconductor industry to bring OTFT‐based flexible electronics into mass production. These requirements are often not met by high‐frequency OTFTs reported in the literature as unconventional processes, such as shadow‐mask patterning or alignment with unrealistic tolerances for production, are used. Here, ultra‐short channel vertical organic field‐effect transistors (VOFETs) with a unity current gain cut‐off frequency (fT) up to 43.2 MHz (or 4.4 MHz V−1) operating below 10 V are shown. Using state‐of‐the‐art manufacturing techniques such as photolithography with reliable fabrication procedures, the integration of such devices down to the size of only 12 × 6 µm2 is shown, which is important for the adaption of this technology in high‐density circuits (e.g., display driving). The intrinsic channel transconductance is analyzed and demonstrates that the frequencies up to 430 MHz can be reached if the parasitic electrode overlap is minimized. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Chlorinated conjugated polymers are rarely reported in ambipolar and n‐type organic thin‐film transistors (OTFTs), mainly due to the lack of chlorinated strong electron‐deficient building blocks. Herein, we report three new chlorine (Cl)‐ and cyano (CN)‐ substituted (E)‐1,2‐di(thiophen‐2‐yl)ethane building blocks and their copolymers P2Cl1CNTVT‐DPP, P4Cl1CNTVT‐DPP and P2Cl2CNTVT‐DPP. P2Cl1CNTVT‐DPP and P2Cl2CNTVT‐DPP had nearly planar backbone geometries, mixture of edge‐on and face‐on orientation and deeper energy levels, while P4Cl1CNTVT‐DPP had a twist backbone geometry, face‐on orientation and shallower energy levels. As a result, P2Cl1CNTVT‐DPP exhibited ambipolar characteristic with hole mobility (μh) of 0.70 cm2·V–1·s–1 and electron mobility (μe) of 0.84 cm2·V–1·s–1 and P2Cl2CNTVT‐DPP exhibited n‐type characteristic with μe of 0.64 cm2·V–1·s–1, while P4Cl1CNTVT‐DPP exhibited the lowest μe of 0.36 cm2·V–1·s–1. The devices based on P2Cl2CNTVT‐DPP exhibited good stability after being stored for 10 d in air. The results demonstrate that by rational molecular design, chlorinated polymers with low cost can be applied to high‐performance ambipolar and n‐type OTFTs. [ABSTRACT FROM AUTHOR]

The development of high‐performance n‐type polymer semiconductors is powered by the design and synthesis of electron‐deficient building blocks with optimized physicochemical properties. By meticulously installing an imide group onto fluorene and its cyanated derivative, we report here two very electron‐deficient building blocks, imide‐functionalized fluorenone (FOI) and its cyanated derivative (FCNI), both featuring a deep‐lying lowest unoccupied molecular orbital energy level down to −4.05 eV and highly coplanar framework, endowing them ideal units for constructing n‐type polymers. Thus, a series of polymers are built from them, exhibiting unipolar n‐type transport character with a highest electron mobility of 0.11 cm2 V−1 s−1. Hence, FOI and FCNI offer a remarkable platform for accessing high‐performance n‐type polymers and the imide functionalization of appropriate (hetero)arenes is a powerful strategy for developing polymers with deep‐lying LUMOs for n‐type organic electronics. [ABSTRACT FROM AUTHOR]

We describe organic thin‐film transistor (OTFT) demonstration by integrating existing photolithographic technology with inkjet printing, eliminating the need for dry etching and significantly reducing material consumption and the number of manufacturing processes, making OTFTs suitable for mass production. OTFTs fabricated this way demonstrate performance superior to that of amorphous silicon. [ABSTRACT FROM AUTHOR]

Abstract The high‐frequency and low‐voltage operation of organic thin‐film transistors (OTFTs) is a key requirement for the commercial success of flexible electronics. Significant progress has been achieved in this regard by several research groups highlighting the potential of OTFTs to operate at several tens or even above 100 MHz. However, technology maturity, including scalability, integrability, and device reliability, is another crucial point for the semiconductor industry to bring OTFT‐based flexible electronics into mass production. These requirements are often not met by high‐frequency OTFTs reported in the literature as unconventional processes, such as shadow‐mask patterning or alignment with unrealistic tolerances for production, are used. Here, ultra‐short channel vertical organic field‐effect transistors (VOFETs) with a unity current gain cut‐off frequency (fT) up to 43.2 MHz (or 4.4 MHz V−1) operating below 10 V are shown. Using state‐of‐the‐art manufacturing techniques such as photolithography with reliable fabrication procedures, the integration of such devices down to the size of only 12 × 6 µm2 is shown, which is important for the adaption of this technology in high‐density circuits (e.g., display driving). The intrinsic channel transconductance is analyzed and demonstrates that the frequencies up to 430 MHz can be reached if the parasitic electrode overlap is minimized.