Using a "multifluorination" strategy, ambipolar donor-acceptor conjugated polymer with hole and electron mobility (μ and μ ) up to 3.94 and 3.50 cm V s , respectively, and unipolar n-type donor-acceptor conjugated polymers with μ up to 4.97 cm V s is synthesized with isoindigo as acceptor units.

Three highly rigid and planar low-bandgap conjugated polymers comprising alternate isoindigo and dithienocarbazole groups are synthesized for the fabrication of high performance polymer solar cells. Power conversion efficiencies of up to 7.2% for conventional devices and 8.2% for inverted devices are demonstrated.

This research underscores the importance of considering both miscibility and molecular ordering in the design of higher efficiency polythiophene (PT):nonfullerene solar cells. We find that ITIC-Th1 exhibits proper miscibility and relatively highly ordered molecular packing with PDCBT-Cl, affording the record performance of >12%. Conversely, due to the excessively high miscibility of PDCBT-Cl and Y6, the system exhibits abysmal photovoltaic efficiency of 0.5%. The results provide efficient guidelines for materials matching of higher efficiency PT:nonfullerene solar cells.

Understanding the key factors influencing the mechanical and electrical properties of semiconducting polymers is crucial to the development of stretchable electronics. In this work, a high-mobility diketopyrrolopyrrole-based conjugated polymer with varied number-average molecular weights (M n ) was used as the model system to explore the impact of molecular weight on the electrical and mechanical properties. Higher-M n films are more ductile and stretchable. Both hole mobilities of thin-film transistors and elastic modulus become maximum at a moderate M n of 88 kg/mol. It was found that film continuity, entanglements, and relative degree of crystallinity are critical factors for approaching the best device performance and highest elastic modulus. The transition molecular weight of a given polymer semiconductor is the key to achieving stretchable high-mobility transistors that are practically useful. This work would help to offer guidance to manipulate the mechanical and electrical properties for other polymer semiconductors.

High-performance unipolar n-type conjugated polymers (CPs) are critical for the development of organic electronics. In the current paper, four "weak donor-strong acceptor" n-type CPs based on pyridine flanked diketopyrrolopyrrole (PyDPP), namely PPyDPP1-4FBT, PPyDPP2-4FBT, PPyDPP1-4FTVT, and PPyDPP2-4FTVT, are synthesized via direct arylation polycondensation by using 3,3′,4,4′-tetrafluoro-2,2′-bithiophene (4FBT) or (E)-1,2-bis(3,4difluorothien-2-yl)ethene (4FTVT) as weak donor unit. All four polymers exhibit low-lying highest occupied molecular orbital (≈ −5.90 eV) and lowest unoccupied molecular orbital energy levels (≈ −3.70 eV). Top-gate/ bottom-contact organic field-effect transistors based on all four polymers display unipolar n-channel characteristics with electron mobility (µ e ) above 1 cm 2 V −1 s −1 in air, and presented linear |I SD | 1/2 −V GS plots and weak dependence of the extracted moblity on gate voltage (V GS ), indicative of the reliability of the extracted mobility values. Importantly, the devices based on PPyDPP1-4FBT and PPyDPP2-4FBT show a pure unipolar n-channel transistor behavior as revealed by the typical unipolar n-channel output characteristics and clear off-regimes in transfer characteristics. Attributed to its high crystallinity and favorable thin film morphology, PPyDPP2-4FBT shows the highest µ e of 2.45 cm 2 V −1 s −1 , which is among the highest for unipolar n-type CPs reported to date. This is also the first report for DPP based pure n-type CPs with µ e greater than 1 cm 2 V −1 s −1 .

Four molecule design strategies of n-type conjugated polymers for organic thin-film transistors are summarized and discussed.

and motion; they would revolutionize present prognosis methods by introducing fast, cheap, and noninvasive alternatives. [3,5,8,13] Soft and flexible sensors can satisfy several mechanical requirements, including conformal attachment to the body, stretchability, and softness, giving greater sensing efficiency. [3,4,6,8,10,14,15] However, devices with these properties are susceptible to mechanical/structural damage (e.g., cracks and scratches), which can result from the combined effect of their soft nature and incompatibility in mechanical stress with human skin. Inevitably, this leads to a lower durability, decreased life-time, and reduced performance in many cases. [16][17][18] To address this issue, one can mimic biological systems by introducing a self-healing capability-a vital property for many organisms in nature-into flexible and soft devices, allowing the recovery of damages without external interventions. [18][19][20][21][22] Excellent progress in the development of new self-healing materials has been made in nonelectronic systems as well as in chemiresistors, supercapacitors, and electrochemical devices. [22][23][24] Nevertheless, field effect transistors (FETs) with extractable multiparameters, offering considerable advantages as a sensor over other competing strategies by delivering a label-free response using a simple electronic readout setup that can be easily miniaturized by employing printed circuit technologies, [25] has not yet been targeted. To prepare FETs, self-healing insulator (dielectric), conductive (electrodes), and semiconductive (channel) materials are required, with the latter being the more challenging. The difficulty of obtaining such material arises from the rigidity of semiconductors because of their conjugated and high crystalline structure, which is contradictory to the softness and high chain mobility of selfhealing materials. Recently, Bao and co-workers have succeeded in synthesizing a healable semiconducting polymer based on 3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione repeating units and nonconjugated 2,6-pyridine dicarboxamide moieties with a µ h of ≈1.4 cm 2 V −1 s −1 , ≈10 6 on/off ratio, and high operating voltages up to −60 V. Nevertheless, the healing process needed solvent treatment or high temperatures for electrical and mechanical recovery with the limitation of selfhealable damage size (<100 nm nanocracks) as well. [26] Indeed, A flexible and stretchable field-effect transistor (FET) is an essential element in a number of modern electronics. To realize the potential of this device in harsh real-world conditions and to extend its application spectrum, new functionalities are needed to be introduced into the device. Here, solution-processable elements based on carbon nanotubes that empower flexible and stretchable FET with high hole-mobility (µ h ≈ 10 cm 2 V −1 s −1 ) and relatively low operating voltages (<8 V) and that retain self-healing properties of all FET components are reported. The device has repeatable intrinsic and autonomic self-heali...

Three thiophene-S,S-dioxidized indophenine (IDTO) isomers, 3 a (E,E,E), 3 b (Z,E,E), and 3 c (Z,E,Z), were synthesized by oxidation of an indophenine compound. 3 b and 3 c could be converted into the most-stable 3 a by heating at 110 °C. An IDTO-containing conjugated polymer, PIDTOTT, was prepared using 3 a as a comonomer through a Stille coupling reaction, and it possesses a narrow band gap and low energy levels. In organic field effect transistors (OFETs), PIDTOTT exhibited unipolar n-type semiconductor characteristics with unexpectedly high electron mobility (up to 0.14 cm(2)  V(-1)  s(-1)), despite its rather disordered chain packing.