Semiconducting Polymer Research Articles

Harnessing the potential of porous carbon derived from chlorinated polyvinyl chloride as an effective gas analyte channel for NO2 organic sensors

Organic electronics fabricated using flexible and lightweight conjugated polymers show substantial potential for use in wearable device applications. Nonetheless, the inherently poor carrier transport characteristics of conjugated polymer semiconductors are a prevalent organic-electronics constraint that limits the sensitivities and response rates of organic gas sensors. In this study, we adhered to the principles of green chemistry and developed high-performance, cost-effective organic gas sensors by introducing stable and conductive porous carbon materials derived from chlorinated polyvinyl chloride (cPVC) into a poly(3-hexylthiophene) (P3HT) matrix. We then investigated how carbonization temperature and the presence of active potassium hydroxide (KOH) in the precursor affect sensing performance. Organic field-effect transistor (OFET) gas sensors manufactured using porous carbon obtained by carbonizing cPVC with KOH at 900 °C (referred to as “K9”) exhibited the best sensing performance, with an eight-fold increase in sensitivity to NO2 gas compared to that of the pristine P3HT-based sensor; it also demonstrated selective NO2-sensing performance in the presence of other oxidizing gases.

Ultralow-Energy-Consumption Photosynaptic Transistor Utilizing Conjugated Polymers/Perovskite Quantum Dots Nanocomposites With Ligand Density Optimization.

The photosynaptic transistor stands as a promising contender for overcoming the von Neumann bottleneck in the realm of photo-communication. In this context, photonic synaptic transistors is developed through a straightforward solution process, employing an organic semiconducting polymer with pendant-naphthalene-containing side chains (PDPPNA) in combination with ligand-density-engineered CsPbBr3 perovskite quantum dots (PQDs). This fabrication approach allows the devices to emulate fundamental synaptic behaviors, encompassing excitatory postsynaptic current, paired-pulse facilitation, the transition from short-to-long-term memory, and the concept of "learning experience." Notably, the phototransistor, incorporating the blend of the PDPPNA and CsPbBr3 PQDs washed with ethyl acetate, achieved an exceptional memory ratio of 104. Simultaneously, the same device exhibited an impressive paired-pulse facilitation ratio of 223% at a moderate operating voltage of -4V and an extraordinarily low energy consumption of 0.215 aJ at an ultralow operating voltage of -0.1mV. Consequently, these low-voltage synaptic devices, constructed with a pendant side-chain engineering of organic semiconductors and a ligand density engineering of PQDs through a simple fabrication process, exhibit substantial potential for replicating the visual memory capabilities of the human brain.

(Invited) Probing the Influence of the Dielectric Environment on Charge Carrier Dynamics in Semiconducting Polymers

Pi-conjugated semiconducting polymers have garnered attention for a variety of electronic and optoelectronic applications, such as field-effect transistors, thermoelectric generators, and photovoltaic devices. In these systems, the charge carrier dynamics are primarily governed by the properties of the polaron and the polymer microstructure. More recently, there has been growing interest in the suitability of these polymer for electrochemical transistors and (photo)electrochemical applications, where the understanding is further complicated by the presence of ions and solvent molecules, as well as the dynamic transport of these species into the semiconducting polymer. Here, we will employ steady-state and transient spectroscopic techniques to probe the influence of charge carrier doping, as well as the extrinsic and local dielectric environments, on charge carrier generation, transport, and recombination in prototypical semiconducting polymer(s). Incorporation of electrochemical techniques enables in-situ spectroscopic measurements that mimic operando conditions. Our observations will provide a better understanding of the factors that control the carrier dynamics in these compositionally complex systems and will have implications for their viability and optimization for (photo)electrochemical applications.

(Invited) Boosting Charge Transport of Polymer Semiconductors and Conductors through Nano Confinement Effects in Skin-Inspired Stretchable Electronics

In this talk, I will discuss the roles of nano confinement effect on charge transport for polymer semiconductors and conductors induced by adding an insulating material in solution. This important phenomenon enabled development of polymer semiconductors and conductors with enhanced charge transport while adding stretchability or self-healing or biodegradable functionalities. This general method is not only important for skin-inspired electronics, but also for polymer electronics in general.

(Invited) Doping at the Extreme in Organic Semiconductors: Challenges and Opportunities

Molecular doping is an effective tool to enhance bulk conductivity, increase carrier injection and de-activate electron or hole traps in organic molecular and polymer semiconductors. Considerable effort has been directed toward the synthesis of powerful and stable p-type and n-type molecular dopants over the past decade.[1,2] This talk reviews a range of molecular redox agents used in organic electronics, with focus on strong reductants and oxidants for organic semiconductors with low electron affinity (EA) and large ionization energy (IE), respectively. In particular, we look at air-stable dimers, e.g. [RuCp*Mes]2, formed of 19-electron organometallic sandwich compounds able to reduce organic semiconductors with EA well below 3 eV.[3] We review powerful single-electron molecular oxidants, e.g. F6-TCNNQ and CN6-CP, which can introduce holes in organic semiconductors with IE larger than 5.6 eV. Applications of these n- and p-dopants to improve the conductivity of carrier injection layers and create large gap semiconductor p-i-n structures are described.[4] The last part of the talk focuses on recent work on adduct-based p-doping of organic semiconductors, applicable to a range of hole transport materials.[5][1]S. Barlow, S.R. Marder, X. Lin, F. Zhang and A. Kahn, Electrical Doping of Organic Semiconductors with Molecular Oxidants and Reductants, Handbook of Conducting Polymers (2019)[2] G. Song, S.B. Kim,S. Mohapatra, Y. Qi, T. Sajoto, A. Kahn, S.R. Marder, S. Barlow, n-Doping of Organic Electronic Materials Using Air-Stable Organometallics, Adv. Mat. 24, 699 (2012)[3] X. Lin, B. Wegner, K. M. Lee, M. A. Fusella, F. Zhang, K. Moudgil, B. P. Rand, S. Barlow, S. R. Marder, N. Kochand A. Kahn, Beating the Thermodynamic Limit: Photo-Activation of n-Doping in Organic Semiconductors, Nature Materials 16, 1209 (2017)[4] H. L. Smith, J. T. Dull, S. Mohapatra, S. Barlow, S. Marder, B. P. Rand, and A. Kahn, Powerful organic molecular oxidant and reductant enable a large gap, blue light-emitting organic homojunction diode, ACS Appl. Mat. Int. 14, 2381 (2022)[5] N. Sakai, R. Warren, F. Zhang, S. Nayak, S. V. Kesava, Y.-H. Lin, H. S. Biswal, X. Lin, A. Kahn, M. Riede, P. K. Nayak and H. J. Snaith, Adduct-based p-doping of Organic Semiconductors, Nature Materials, 20, 1248 (2021)

(Invited) Point-of-Care Biomembrane-Based Electronic Sensors

The development of medical devices that comply with the soft mechanics of biological systems at different length and complexity levels is highly desirable. With the emergence of conducting polymers exciting directions opened up in bioelectronics research, bridging the gap between traditional electronics and biology. With the ultimate goal of fully integrated devices, organic bioelectronic technologies have been heavily explored the past decade resulting in novel materials/device configurations. Multiplexing capability, ability to adopt to complex performance requirements in biological fluids, sensitivity, stability, literal flexibility and compatibility with large-area processes are only some of the merits of this technology for biomedical applications. A recent example of a bio-integrated electronic device, the BiOET, is based on polymeric semiconductor technology and is fabricated using nano/micro-fabrication methods in conjunction with synthetic biology approaches to incorporate hierarchically organized biological models of the cell membrane. Despite their significance, cell membranes are still an underexplored target for studying the mechanisms of diseases or drug therapies. Cell-free commercially available technologies for cell membrane studies have been limited to synthetic membranes that lack the inherent complexity found in the membrane of the cell. In this talk I will describe a method to create native cell membranes, using vesicles derived from live cells, on top of conducting polymer- based microfabricated electrodes and transistors. The activity of transmembrane proteins in response to different stimuli can be electrically monitored, offering a direct means to characterize drug toxicity or potency at the critical first contact point: membrane interaction.

Deciphering single-cell transcriptomic landscape of tumors in colorectal cancer treated with photothermal semiconducting polymers to design the combination therapy with checkpoint blockades for inhibition of tumor progression and metastasis

Immunotherapy is often less effective for tumors with “immune-excluded,” or “immune-desert” microenvironment. To circumvent this hurdle, new therapeutic strategies need to be designed to reprogram the tumor microenvironment (TME). It is well known that photothermal therapy (PTT) can prime the TME and provoke the systemic anti-tumor immunity. But few studies perform extensive exploration in depth to decipher the changes in TME after PTT with cutting-edge technology besides conventional flow cytometry analysis. In this study, we designed a nanosystem consisting of organic semiconductor polymer liposome nanoparticles (Y8 NPs) as a multimodal imaging and photothermal agent to image and treat tumors. Upon laser irradiation, Y8 NPs in tumors could rapidly increase the temperature, induce massive cancer cell apoptosis and also promote the immunogenic cell death (ICD), ultimately remodulating the TME. We employed single cell RNA sequencing (scRNA-seq) technology to comprehensively explore transcriptomic profiling of individual cells constituting TME, demonstrating heterogenous alterations in the subtypes of immune cells, even tumor cells. Considering the findings by scRNA-seq and TME remodulation, the combinational strategy with checkpoint blockade PD-1 antibody was designed to treat the tumors, demonstrating that the combination not only impedes primary tumor progression but also produce profound abscopal anti-tumor effect. In conclusion, we provide a simple strategy for the remodulation of TME with a photothermal nanosystem to achieve activation of anti-tumor immunity, and suppress primary and metastatic tumor progression.

3-Methyl Thiophene-Modified Boron-Doped Diamond (BDD) Electrodes as Efficient Catalysts for Phenol Detection-A Case Study for the Detection of Gallic Acid in Three Specific Tea Types.

Polymer modification has been established as a cost-effective, simple, in situ method for overcoming some of the inherent disadvantages of boron-doped diamond (BDD) electrodes, and its application has been extended to reliable, low-cost environmental monitoring solutions. The present review focuses on modifying BDD electrodes with semi-conductive polymers acting as redox mediators. This article reports on the development of a 3-methyl thiophene-modified boron-doped diamond (BDD/P3MT) sensor for the electrochemical determination of total phenolic compounds (TPCs) in tea samples, using gallic acid (GA) as a marker. GA is a significant polyphenol with various biological activities, making its quantification crucial. Thus, a simple, fast, and sensitive GA sensor was fabricated using the electroanalytical square wave voltammetry (SWV) technique. The sensor utilizes a semi-conductive polymer, 3-methyl thiophene, as a redox mediator to enhance BDD's sensitivity and selectivity. Electrochemical synthesis was used for polymer deposition, allowing for greater purity and avoiding solubility problems. The BDD/P3MT sensor exhibits good electrochemical properties, including rapid charge transfer and a large electrochemical area, enabling GA detection with a limit of detection of 11 mg/L. The sensor's response was correlated with TPCs measured by the Folin-Ciocalteu method. Square wave voltammetry (SWV) showed a good linear relationship between peak currents and GA concentrations in a wide linear range of 3-71 mg/L under optimal conditions. The BDD/P3MT sensor accurately measured TPCs in green tea, rooibos tea, and black tea samples, with green tea exhibiting the highest TPC levels. The results demonstrate the potential of the modified BDD electrode for the rapid and accurate detection of phenolic compounds in tea, with implications for quality control and antioxidant activity assessments. The prolific publications of the past decade have established BDD electrodes as robust BDD sensors for quantifying polyphenols. Fruits, vegetables, nuts, plant-derived beverages such as tea and wine, traditional Eastern remedies and various herbal nutritional supplements contain phenolic chemicals. The safety concerns of contaminated food intake are significant health concerns worldwide, as there exists a critical nexus between food safety, nutrition, and food security. It has been well established that green tea polyphenol consumption promotes positive health effects. Despite their potential benefits, consuming high amounts of these polyphenols has sparked debate due to concerns over potential negative consequences.

Utilizing Secondary Bonds Formed by Halogen Substituents: Achieving the Dynamic Transition of Low-Bandgap Semiconductor Polymers from Macromolecules to Small Molecules

Utilizing Secondary Bonds Formed by Halogen Substituents: Achieving the Dynamic Transition of Low-Bandgap Semiconductor Polymers from Macromolecules to Small Molecules

Semiconducting polymer nanoprodrugs enable tumor-specific therapy via sono-activatable ferroptosis

Ferroptosis, a recently identified form of cell death, holds promise for cancer therapy, but concerns persist regarding its uncontrolled actions and potential side effects. Here, we present a semiconducting polymer nanoprodrug (SPNpro) featuring an innovative ferroptosis prodrug (DHU-CBA7) to induce sono-activatable ferroptosis for tumor-specific therapy. DHU-CBA7 prodrug incorporate methylene blue, ferrocene and urea bond, which can selectively and specifically respond to singlet oxygen (1O2) to turn on ferroptosis action via rapidly cleaving the urea bonds. DHU-CBA7 prodrug and a semiconducting polymer are self-assembled with an amphiphilic polymer to construct SPNpro. Ultrasound irradiation of SPNpro leads to the production of 1O2 via sonodynamic therapy (SDT) of the semiconducting polymer, and the generated 1O2 activated DHU-CBA7 prodrug to achieve sono-activatable ferroptosis. Consequently, SPNpro combine SDT with the controlled ferroptosis to effectively cure 4T1 tumors covered by 2-cm tissue with a tumor inhibition efficacy as high as 100 %, and also completely restrain tumor metastases. This study introduces a novel sono-activatable prodrug strategy for regulating ferroptosis, allowing for precise cancer therapy.

Using a Flexible Fountain Pen to Directly Write Organic Semiconductor Patterns with Crystallization Regulated by the Precursor Film.

Organic semiconductor (OSC) films fabricated by meniscus-guided coating (MGC) methods are suitable for cost-effective and flexible electronics. However, achieving crystalline thin films by MGC methods is still challenging because the nucleation and crystal growth processes are influenced by the intertwined interactions among solvent evaporation, stochastic nucleation, and the fluid flow instabilities. Herein, a novel flexible fountain pen with active ink supply is designed and used to print OSCs. This direct-write method allows the flexible pen tip to contact the substrate, maintaining a robust meniscus by eliminating the gap found in conventional MGCs. An in situ optical microscopy observation system shows that the precursor film plays a critical role on the crystallization and the formation of coffee rings and dendrites. The computational fluid dynamics simulations demonstrate that the microstructure of the pen promotes extensional flows, facilitating mass transport and crystal alignment. Highly-aligned ribbon-shaped crystals of a small organic molecule (TIPS-pentacene), as well as a semiconducting polymer (N2200) with highly-ordered orientations, have been successfully printed by the flexible fountain pen. Organic field-effect transistors based on the flexible pen printed OSCs exhibit high performances and strong anisotropic mobility. In addition, the flexible fountain pen is expandable for printing multiple lines or large-area films.

Synchronously Manipulating the D−A Interaction and Planarity in Semiconducting Polymers to Achieve 84.7% Photothermal Conversion Efficiency for NIR‐II Imaging‐Guided Tumor Therapy

AbstractExploiting photothermal agents with second‐near‐infrared (NIR‐II, 1000−1700 nm) emission and a high photothermal conversion efficiency (PCE) is an appealing and challenging task. Herein, by simultaneously tailoring the D−A interaction and planarity in fluorophores, two donor‐acceptor (D−A) −type semiconducting polymers (SPs), T‐BTP and B‐BTP, are constructed. Compared with T‐BTP, B‐BTP shows increased intramolecular interactions and improved molecular planarity, leading to bathochromic‐shift absorption, NIR‐II emission, and high PCE. Notably, the B‐BTP NPs achieve a remarkable PCE of 84.7%, which is among the highest PCEs of SPs in NIR‐II fluorescence imaging‐guided photothermal therapy (PTT). Because of these promising features, B‐BTP NPs are successfully used in NIR‐II vascular imaging and cancer therapy. This study provides valuable guidelines for the development of high‐performance NIR‐II SPs.

Effects of Planarization of the Triphenylamine Unit on the Electronic and Transport Properties of Triarylamine-Fluorene Copolymers in Both Doped and Undoped Forms.

Triarylamine-alt-fluorene (TAF) copolymers are widely used for hole injection and transport in organic electronics. Despite suggestions to planarize the triphenylamine moiety, little research has been conducted. Here, we report a comprehensive investigation of the effects of planarization on the electronic and transport properties of a model TAF polymer semiconductor core. We compared the conventional twisted-propeller N-4-methoxyphenyl-N,N-diphenylamine-4',4″-diyl (TA) unit and its planarized bridged analogue (bTA) where adjacent o,o'-positions are linked by 1,1-dimethylmethylene. We studied both polyelectrolyte and non-polyelectrolyte forms of this core in both doped and undoped states. We found that planarization leads to an unprecedented trap-free transport of holes, and a pronounced enhancement of their mobility in the undoped state though less so in the doped state. Planarization also induces a slight reduction in the ionization energy of the undoped polymer, consequently lowering the work function of the doped polymer. This is accompanied by small spectral shifts: a red shift in the first absorption band of the undoped polymer and a blue shift in the first absorption band of the polaron. Furthermore, this study unveils new fundamental features of TAF polymers: (i) Doping induces the formation of three polaron bands within the subgap. (ii) Absorption of both neutral and polaron segments exhibit a linear intensity relationship with doping level. (iii) Electrical conductivity reaches a maximum at the half-doped state, varying as σ ∼ (x (1 - x))3 for 0.1 ≲ x ≲ 0.9, where x is the doping level. Finally, we demonstrate the successful integration of these self-compensated hole-doped TAF polymers as efficient hole injection layers in organic semiconductor diodes.

II-Scheme Heterojunction Frameworks Based on Covalent Organic Frameworks and HKUST-1 for Boosting Photocatalytic Hydrogen Evolution.

Covalent organic frameworks (COFs) are one type of promising polymer semiconductors in solar-driven hydrogen production, but majority of COFs-based photocatalytic systems show low photocatalytic efficiency owing to lack of metal active sites. Herein, we reported II-Scheme heterojunction frameworks based on COF (TpPa-1) and metal-organic framework (HKUST-1) for highly efficient hydrogen production. The coordination bonding directed self-assembly of HKUST-1 on the surface of TpPa-1 endows the heterojunction frameworks (HKUST-1/TpPa-1) with strong interface interaction, optimized electronic structures and abundant redox active sites, thus remarkably boosting photocatalytic hydrogen evolution. The hydrogen evolution rate for optimal HKUST-1/TpPa-1 is as high as 10.50 mmol g-1 h-1, which is significantly enhanced when compared with that of their physical mixture (4.13 mmol g-1 h-1), TpPa-1 (0.013 mmol g-1 h-1) and Pt-based counterpart (6.70 mmol g-1 h-1). This work offers a facile approach to the construction of noble-metal-free II-Scheme heterojunctions based on framework materials for efficient solar energy conversion.

A polymer–semiconductor–ceramic cantilever for high-sensitivity fluid-compatible microelectromechanical systems

A polymer–semiconductor–ceramic cantilever for high-sensitivity fluid-compatible microelectromechanical systems

Synthesis of thienopyrazine‐ and cyclofluorene–thiophene‐based donor–acceptor low‐band gap polymers and their application in memory devices

AbstractLow‐band gap semiconductor polymer materials play a crucial role in the field of organic optoelectronics. In this context, a series of low‐band gap polymers containing thienopyrazine as the acceptor and cyclofluorene–bithiophene as the donor were synthesized and utilized in resistive random access memory (RRAM) devices. These memory devices consistently exhibit nonvolatile flash memory behavior. Remarkably, all three polymers demonstrate stability even after 1000 cycles without significant fluctuations. Notably, the three polymer‐based devices also exhibit excellent ternary memory performance, with current ratios of 1:102.8:104, 1:101.3:103.9, and 1:101.8:103.6. Furthermore, the photoelectric properties of the three polymers and the conduction mechanisms of the memory devices were thoroughly discussed.

Neutrophil-based Trojan horse containing polymer nano-therapeutics for sono-activatable ferroptosis-immunotherapy of orthotopic glioma

The blood-brain barrier (BBB) and tumor microenvironment of glioma limit the efficacies of various therapies, and thus glioma treatment is challenging. We herein report semiconducting polymer nano-therapeutics (SPCFe/siP) that can achieve efficient delivery into orthotopic glioma sites via neutrophil-mediated BBB transport for sono-activatable ferroptosis-immunotherapy. Such SPCFe/siP contain a semiconducting polymer, programmed death-ligand 1 (PD-L1) siRNA and iron oxide (Fe3O4) nanoparticles loaded into a singlet oxygen (1O2)-cleavable nanocarrier with surface conjugation of a neutrophil targeting ligand, sialic acid. SPCFe/siP effectively bind to neutrophils via sialic acid-based targeting pathway, and neutrophils containing SPCFe/siP serve as Trojan horses to migrate across BBB for improved delivery efficacy into orthotopic glioma sites. Upon irradiation by ultrasound (US), the semiconducting polymers produce 1O2 to destroy 1O2-cleavable nanocarriers for precise on-demand releases of Fe3O4 nanoparticles and PD-L1 siRNA, in which, Fe3O4 nanoparticles induce ferroptosis and subsequent immunogenic cell death (ICD), and PD-L1 siRNA downregulated the expression of PD-L1 for tumor cells, allowing for sono-activatable ferroptosis-immunotherapy. A strong immunological effect is formed, leading to noteworthy restriction of orthotopic glioma tumor growth and improvement of mouse survival. This study provides a neutrophil-targeting nanosystem with efficient brain delivery and activatable therapeutic action for treatment of orthotopic glioma.

On-Demand Catalysed n-Doping of Organic Semiconductors.

A new approach to control the n-doping reaction of organic semiconductors is reported using surface-functionalized gold nanoparticles (f-AuNPs) with alkylthiols acting as the catalyst only upon mild thermal activation. To demonstrate the versatility of this methodology, the reaction of the n-type dopant precursor N-DMBI-H with several molecular and polymeric semiconductors at different temperatures with/without f-AuNPs, vis-à-vis the unfunctionalized catalyst AuNPs, was investigated by spectroscopic, morphological, charge transport, and kinetic measurements as well as, computationally, the thermodynamic of catalyst activation. The combined experimental and theoretical data demonstrate that while f-AuNPs is inactive at room temperature both in solution and in the solid state, catalyst activation occurs rapidly at mild temperatures (~70 °C) and the doping reaction completes in few seconds affording large electrical conductivities (~10-140 S cm-1). The implementation of this methodology enables the use of semiconductor+dopant+catalyst solutions and will broaden the use of the corresponding n-doped films in opto-electronic devices such as thin-film transistors, electrochemical transistors, solar cells, and thermoelectrics well as guide the design of new catalysts.

On‐Demand Catalysed n‐Doping of Organic Semiconductors

AbstractA new approach to control the n‐doping reaction of organic semiconductors is reported using surface‐functionalized gold nanoparticles (f‐AuNPs) with alkylthiols acting as the catalyst only upon mild thermal activation. To demonstrate the versatility of this methodology, the reaction of the n‐type dopant precursor N‐DMBI‐H with several molecular and polymeric semiconductors at different temperatures with/without f‐AuNPs, vis‐à‐vis the unfunctionalized catalyst AuNPs, was investigated by spectroscopic, morphological, charge transport, and kinetic measurements as well as, computationally, the thermodynamic of catalyst activation. The combined experimental and theoretical data demonstrate that while f‐AuNPs is inactive at room temperature both in solution and in the solid state, catalyst activation occurs rapidly at mild temperatures (~70 °C) and the doping reaction completes in few seconds affording large electrical conductivities (~10–140 S cm−1). The implementation of this methodology enables the use of semiconductor+dopant+catalyst solutions and will broaden the use of the corresponding n‐doped films in opto‐electronic devices such as thin‐film transistors, electrochemical transistors, solar cells, and thermoelectrics well as guide the design of new catalysts.

Intrinsically Elastic Semiconductors through Aldehyde-Amine Polycondensation and Its Application on Stretchable Transistor.

With the increasing demand for elastic electronics, as a crucial component, elastic semiconductors have been widely studied. However, there are some issues for the current preparation of elastic semiconductors, such as harsh reaction conditions, low atomic economic utilization, and complicated product separation and purification. Aldehyde-amine polycondensation is an important chemical reaction with the advantages of mild reaction conditions, high atomic-economic efficiency, and easy separation and purification. Herein, intrinsically elastic semiconductors are developed via aldehyde-amine polycondensation, including a semiconducting segment and an elastic segment. The resulting polymer containing 42.62 wt % soft segments exhibits excellent stretchability and mechanical reversibility, especially with a lower modulus. Interestingly, the carrier mobility displays up to 0.04 cm2·V-1·s-1, in the range of the fully conjugated reference polymer (0.1 cm2·V-1·s-1). In brief, this strategy provides important guiding principles for the development of intrinsically elastic polymer semiconductors.