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Abstract The development of intrinsically stretchable polymer semiconductor holds substantial promise in the field of wearable electronics. However, charge transport mobility is typically compromised in existing stretchable semiconductors to achieve the desired stretchability. Herein, a novel “regional conjugation” strategy is proposed to design an intrinsically stretchable polymer semiconductor oligo‐diketopyrrolopyrrole‐thieno[3,2‐b]thiophene (DPPTT)–urethane, in which oligo‐DPPTT conjugated units and alkyl urethane nonconjugated units are introduced. The regional conjugation of oligo‐DPPTT in the polymer backbone endows DPPTT–urethane with good molecular packing, leading to a high mobility of up to 1.7 cm2 V−1 s−1. Additionally, incorporating alkyl urethane nonconjugated units in the backbone can reduce film crystallinity and chain aggregation, which contribute to the stretchability of the polymer thin film. Consequently, fully stretchable transistors retain carrier mobility even at 100% biaxial tensile strain. Furthermore, the fully stretchable organic field‐effect transistor arrays show remarkable charge transport reversibility and durability after 1000 stretch–release cycles at 25% strain. Additionally, the device exhibits extraordinary electrical stability in air atmosphere. Overall, these results indicate that the “regional conjugation” strategy provides an effective and promising methodology to design intrinsically stretchable and high‐performance polymer semiconductor that can advance the development of soft and wearable electronics.

Oligomers and polymers consisting of multiple thiophenes are widely used in organic electronics such as organic transistors and sensors because of their strong electron-donating ability. In this study, a solution to the problem of the poor solubility of polythiophene systems was developed. A novel π-conjugated polymer material, PDPP-5Th, was synthesized by adding the electron acceptor unit, DPP, to the polythiophene system with a long alkyl side chain, which facilitated the solution processing of the material for the preparation of devices. Meanwhile, the presence of the multicarbonyl groups within the DPP molecule facilitated donor–acceptor interactions in the internal chain, which further improved the hole-transport properties of the polythiophene-based material. The weak forces present within the molecules that promoted structural coplanarity were analyzed using theoretical simulations. Furthermore, the grazing incidence wide-angle X-ray scanning (GIWAXS) results indicated that PDPP-5Th features high crystallinity, which is favorable for efficient carrier migration within and between polymer chains. The material showed hole transport properties as high as 0.44 cm2 V−1 s−1 in conductivity testing. Our investigations demonstrate the great potential of this polymer material in the field of optoelectronics.

Organic dye semiconductors have received increasing attention as the next generation of semiconductors, and one of their potential applications is as a core component of organic transistors. In this study, two novel diketopyrrolopyrrole (DPP) dye core-based materials were designed and separately prepared using Stille coupling reactions under different palladium catalyst conditions. The molecular weights and elemental compositions were tested to demonstrate that both catalysts could be used to successfully prepare materials of this structure, with the main differences being the weight-average molecular weight and the dispersion index. PDPP-2Py-2Tz I with a longer conjugation length exhibited better thermodynamic stability than the counterpart polymer PDPP-2Py-2Tz II. The intrinsic optical properties of the polymers were relatively similar, while the electrochemical tests showed small differences in their energy levels. The polymers obtained with different catalysts displayed similar and moderate electron mobility in transistor devices, while PDPP-2Py-2Tz I possessed a higher switching ratio. Our study provides a comparison of such dye materials under different catalytic conditions and also demonstrates the great potential of dye materials for optoelectronic applications.

The article in Advanced Electronic Materials discusses a new approach called "regional conjugation" to create an intrinsically stretchable polymer semiconductor for use in stretchable electronics. The strategy developed by Zhihui Wang, Zhengran Yi, and their team allows for high-performance charge transport in fully stretchable transistors even under significant mechanical strain. This innovative method shows promise for the future development of durable and flexible polymer thin film electronics. [Extracted from the article]

The design of novel acceptor molecular structures based on classical building blocks is regarded as one of the efficient ways to explore the application of organic conjugated materials in conductivity and electronics. Here, a novel acceptor moiety, thiophene-vinyl-diketopyrrolopyrrole (TVDPP), was envisioned and prepared with a longer conjugation length and a more rigid structure than thiophene-diketopyrrolopyrrole (TDPP). The brominated TVDPP can be sequentially bonded to trimethyltin-containing benzo[c][1,2,5]thiadiazole units via Suzuki polycondensation to efficiently prepare the polymer PTVDPP-BSz, which features high molecular weight and excellent thermal stability. The polymerization process takes only 24 h and eliminates the need for chlorinated organic solvents or toxic tin-based reagents. Density functional theory (DFT) simulations and film morphology analyses verify the planarity and high crystallinity of the material, respectively, which facilitates the achievement of high carrier mobility. Conductivity measurements of the polymeric material in the organic transistor device show a hole mobility of 0.34 cm2 V−1 s−1, which illustrates its potential for functionalized semiconductor applications. [ABSTRACT FROM AUTHOR]

Oligomers and polymers consisting of multiple thiophenes are widely used in organic electronics such as organic transistors and sensors because of their strong electron-donating ability. In this study, a solution to the problem of the poor solubility of polythiophene systems was developed. A novel π-conjugated polymer material, PDPP-5Th, was synthesized by adding the electron acceptor unit, DPP, to the polythiophene system with a long alkyl side chain, which facilitated the solution processing of the material for the preparation of devices. Meanwhile, the presence of the multicarbonyl groups within the DPP molecule facilitated donor–acceptor interactions in the internal chain, which further improved the hole-transport properties of the polythiophene-based material. The weak forces present within the molecules that promoted structural coplanarity were analyzed using theoretical simulations. Furthermore, the grazing incidence wide-angle X-ray scanning (GIWAXS) results indicated that PDPP-5Th features high crystallinity, which is favorable for efficient carrier migration within and between polymer chains. The material showed hole transport properties as high as 0.44 cm2 V−1 s−1 in conductivity testing. Our investigations demonstrate the great potential of this polymer material in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

Organic dye semiconductors have received increasing attention as the next generation of semiconductors, and one of their potential applications is as a core component of organic transistors. In this study, two novel diketopyrrolopyrrole (DPP) dye core-based materials were designed and separately prepared using Stille coupling reactions under different palladium catalyst conditions. The molecular weights and elemental compositions were tested to demonstrate that both catalysts could be used to successfully prepare materials of this structure, with the main differences being the weight-average molecular weight and the dispersion index. PDPP-2Py-2Tz I with a longer conjugation length exhibited better thermodynamic stability than the counterpart polymer PDPP-2Py-2Tz II. The intrinsic optical properties of the polymers were relatively similar, while the electrochemical tests showed small differences in their energy levels. The polymers obtained with different catalysts displayed similar and moderate electron mobility in transistor devices, while PDPP-2Py-2Tz I possessed a higher switching ratio. Our study provides a comparison of such dye materials under different catalytic conditions and also demonstrates the great potential of dye materials for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Organic polymer semiconductor materials, due to their good chemical modifiability, can be easily tuned by rational molecular structure design to modulate their material properties, which, in turn, affects the device performance. Here, we designed and synthesized a series of materials based on terpolymer structures and applied them to organic thin-film transistor (OTFT) device applications. The four polymers, obtained by polymerization of three monomers relying on the Stille coupling reaction, shared comparable molecular weights, with the main structural difference being the ratio of the thiazole component to the fluorinated thiophene (Tz/FS). The conjugated polymers exhibited similar energy levels and thermal stability; however, their photochemical and crystalline properties were distinctly different, leading to significantly varied mobility behavior. Materials with a Tz/FS ratio of 50:50 showed the highest electron mobility, up to 0.69 cm2 V−1 s−1. Our investigation reveals the fundamental relationship between the structure and properties of materials and provides a basis for the design of semiconductor materials with higher carrier mobility. [ABSTRACT FROM AUTHOR]

Organic polymer semiconductor materials are conveniently tuned to energy levels because of their good chemically modifiable properties, thus enhancing their carrier transport capabilities. Here, we have designed and prepared a polymer with a donor-acceptor structure and tested its potential as a p-type material for organic field-effect transistor (OFET) applications using a solution-processing method. The conjugated polymers, obtained via the polymerization of the two monomers relying on the Stille coupling reaction, possess extremely high molecular weights and thermodynamic stability. Theoretical-based calculations show that PDPP-2S-Se has superior planarity, which is favorable for carrier transport within the main chain. Photophysical and electrochemical measurements systematically investigated the properties of the material and the energy levels with respect to the theoretical values. The maximum hole mobility of the PDPP-2S-Se-based OFET device is 0.59 cm2 V−1 s−1, which makes it a useful material for potential organic electronics applications. [ABSTRACT FROM AUTHOR]

The development of n-type organic semiconductor materials for transporting electrons as part of logic circuits is equally important to the development of p-type materials for transporting holes. Currently, progress in research on n-type materials is relatively backward, and the number of polymers with high electron mobility is limited. As the core component of the organic field-effect transistor (OFET), the rational design and judicious selection of the structure of organic semiconductor materials are crucial to enhance the performance of devices. A novel conjugated copolymer with an all-acceptor structure was synthesized based on an effective chemical structure modification and design strategy. PDPPTT-2Tz was obtained by the Stille coupling of the DPPTT monomer with 2Tz-SnMe3, which features high molecular weight and thermal stability. The low-lying lowest unoccupied molecular orbital (LUMO) energy level of the copolymer was attributed to the introduction of electron-deficient bithiazole. DFT calculations revealed that this material is highly planar. The effect of modulation from a donor–acceptor to acceptor–acceptor structure on the improvement of electron mobility was significant, which showed a maximum value of 1.29 cm2 V−1 s−1 and an average value of 0.81 cm2 V−1 s−1 for electron mobility in BGBC-based OFET devices. Our results demonstrate that DPP-based polymers can be used not only as excellent p-type materials but also as promising n-type materials. [ABSTRACT FROM AUTHOR]

Stretchable electronics have received intense attention due to their broad application prospects in many areas, and can withstand large deformations and form close contact with curved surfaces. Stretchable conductors are vital components of stretchable electronic devices used in wearables, soft robots, and human–machine interactions. Recent advances in stretchable conductors have motivated basic scientific and technological research efforts. Here, we outline and analyse the development of stretchable conductors in transistors and circuits, and examine advances in materials, device engineering, and preparation technologies. We divide the existing approaches to constructing stretchable transistors with stretchable conductors into the following two types: geometric engineering and intrinsic stretchability engineering. Finally, we consider the challenges and outlook in this field for delivering stretchable electronics. [ABSTRACT FROM AUTHOR]

Organic field‐effect transistor (OFET)‐based circuits require stable device performance. However, OFETs are suffering from process variation and environmental instability, which limits circuit performance. Here, an optimally designed XOR gate based on p‐type‐only OFETs is reported. The circuit has excellent postfabrication tunability that is enough to cope with a threshold voltage shift as high as 1.5 V. Moreover, the circuit largely reduces the number of transistors by 81% compared with conventional design and can realize ultralow power consumption. In addition, the XOR gate can act as a programmable inverter with good regenerative property. Utilizing the XOR gate, the authors demonstrate its application in cryptography. A 3481‐bit message is correctly encrypted and decrypted with an accuracy rate of up to 98.5%. The authors' work enables the accurate prediction of circuit operation in the presence of OFET threshold voltage shifts. [ABSTRACT FROM AUTHOR]

Cu‐benzenehexathiol (Cu‐BHT) has attracted significant attention due to its record high electrical conductivity and crystal defects Cu2c. However, the nonporous structure and small specific surface area of Cu‐BHT with two‐dimensional kagome lattice invariably limit its practical application in sensing and catalysis. In this work, Cu‐BHT nanotubes (Cu‐BHT‐NTs) are designed and prepared via a facile homogeneous reaction to solve these problems. Compared with the traditional nanorod‐like structure, the Cu‐BHT‐NTs not only have a higher specific surface area but also possess a higher proportion of crystal defects (66.6%). The successfully configured DPPTT/Cu‐BHT‐NTs heterostructure organic field‐effect transistor (OFET)‐based sensor exhibits excellent sensitivity as high as 13 610%, a minimum detection limits down to 5 ppb, and exceptional selectivity to nitric oxide (NO) toxic gases. Theoretical analysis systematically shows that Cu2c sites in the Cu‐BHT‐NTs increase the number of electrons transferred from the heterostructure to NO molecules, confirming that the high sensitivity and selectivity result from the high binding between Cu‐BHT‐NTs and NO molecules. Furthermore, a fully flexible device based on the heterojunction OFET sensor is prepared to ensure the convenience of wearing and carrying gas sensors, opening up a new avenue for the next generation of wearable intelligent electronics. [ABSTRACT FROM AUTHOR]

Thermal energy transfer across a silicon-aluminum thin films pair is considered. The thin films pair is thermally disturbed from the silicon film edge by a repetitive temperature pulses while phonon transport in the film pairs is examined. The transient frequency dependent Boltzmann transport equation is solved numerically incorporating the appropriate initial and boundary conditions. Thermal boundary resistance is adopted at the thin films interface and electron-phonon coupling is introduced to account for the thermal communication of electron and lattice subsystems in the aluminum film. The influence of repetition of temperature disturbance on the phonon transport characteristics is assessed. The numerical code developed is validated through the thermal conductivity data reported in the previous study. It is found that thermal conductivity predictions agree well with the experimental data. The long pulse temperature disturbance from the silicon edge results in large phonon intensity oscillations in the silicon and the aluminum films. The ballistic phonons contribute significantly to damping of phonon intensity oscillations in the silicon film. The magnitude of temperature jump at the film edges and the films pair interface remains low for the frequency dependent solution of the Boltzmann equation. [ABSTRACT FROM AUTHOR]

The development of efficient, low-cost, and durable electrocatalysts toward both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is of great significance for overall water splitting associated with renewable energy conversion and storage. Carbon-based nanomaterials have been widely employed as electrocatalysts for the independent HER or OER; however, research on bifunctional metal-free electrocatalysts for water splitting is still in its infancy and remains a formidable challenge to develop highly active catalysts for future applications. Here we report a highly active defect-rich, carbon-based, bifunctional metal-free water splitting electrocatalyst, prepared by a template approach, in which a nitrogen-enriched polydopamine analogue is used as the carbon precursor. The resultant defect-rich porous carbon (DRPC) exhibits a large specific surface area with a hierarchically micro/mesoporous structure and a high nitrogen doping content with rich pyridinic N. Accordingly, the newly developed DRPC electrocatalysts display superb bifunctional catalytic activities for both the HER and the OER in alkaline solution, outperforming all other reported metal-free catalysts. Significantly, the DRPC catalyst couple-based alkaline water electrolyzer with strong durability delivers a 10 mA cm−2 overall water splitting current at a considerably low voltage of 1.74 V, and a demonstration of a self-powered electrochemical water splitting system is also presented, highlighting its great potential for practical applications. [ABSTRACT FROM AUTHOR]

A table of contents for the issue is presented.

A bioinspired polydopamine derivative was prepared by self-polymerization of 6-(2-aminoethyl)-3-hydroxypyridin-2(1H)-one (AHPO) in an alkaline aqueous medium. It was used as a precursor to produce nanocapsules of pyridinic N-rich carbon with a desired N doping content by using silica nanoparticles as the template. These N-doped nanocapsules exhibited superior electrocatalytic activity and stability towards the oxygen reduction reaction (ORR), lending an attractive alternative to the Pt catalyst. This work provides an important insight into the rational designing of bioinspired polymers for the development of functional carbon materials with excellent properties. [ABSTRACT FROM AUTHOR]

A table of contents for the 2015 issue of "Journal of Materials Chemistry C" is presented.