Search

N‐type conjugated polymers as the semiconducting component of organic electrochemical transistors (OECTs) are still undeveloped with respect to their p‐type counterparts. Herein, we report two rigid n‐type conjugated polymers bearing oligo(ethylene glycol) (OEG) side chains, PgNaN and PgNgN, which demonstrated an essentially torsion‐free π‐conjugated backbone. The planarity and electron‐deficient rigid structures enable the resulting polymers to achieve high electron mobility in an OECT device of up to the 10−3 cm2 V−1 s−1 range, with a deep‐lying LUMO energy level lower than −4.0 eV. Prominently, the polymers exhibited a high device performance with a maximum dimensionally normalized transconductance of 0.212 S cm−1 and the product of charge‐carrier mobility μ and volumetric capacitance C* of 0.662±0.113 F cm−1 V−1 s−1, which are among the highest in n‐type conjugated polymers reported to date. Moreover, the polymers are synthesized via a metal‐free aldol‐condensation polymerization, which is beneficial to their application in bioelectronics. [ABSTRACT FROM AUTHOR]

From established to emergent technologies, doping plays a crucial role in all semiconducting devices. Doping could, theoretically, be an excellent technique for improving repressively low transconductances in n-type organic electrochemical transistors – critical for advancing logic circuits for bioelectronic and neuromorphic technologies. However, the technical challenge is extreme: n-doped polymers are unstable in electrochemical transistor operating environments, air and water (electrolyte). Here, the first demonstration of doping in electron transporting organic electrochemical transistors is reported. The ammonium salt tetra-n-butylammonium fluoride is simply admixed with the conjugated polymer poly(N,N'-bis(7-glycol)-naphthalene-1,4,5,8-bis(dicarboximide)-co-2,2'-bithiophene-co-N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide), and found to act as a simultaneous molecular dopant and morphology-additive. The combined effects enhance the n-type transconductance with improved channel capacitance and mobility. Furthermore, operational and shelf-life stability measurements showcase the first example of water-stable n-doping in a polymer. Overall, the results set a precedent for doping/additives to impact organic electrochemical transistors as powerfully as they have in other semiconducting devices. Improving electron transport and stability of n-type organic electrochemical transistors (OECTs) is required to realize a commercially-viable technology for bioelectronics applications. Here, the authors report water-stable doped n-type OECTs with enhanced transconductance and record stability. [ABSTRACT FROM AUTHOR]

Nanomedicines that inhibit/disassemble amyloid β (Aβ) aggregates in Alzheimer's disease (AD) are highly desirable yet remain challenging. Therapeutic efficacy and systemic delivery of reported molecules and nanoparticles (NPs) are hampered by various challenges, including low biocompatibility, off‐target toxicity, and lack of specificity. Herein, a versatile NP is designed by integrating high Aβ‐binding affinity, stimuli‐responsive drug release, and photothermal degradation properties for efficient disassembly of Aβ. Near‐infrared (NIR)‐absorbing conjugated polymer PDPP3T‐O14 serves as a photothermal core while thermal‐responsive polymer 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine at the outer layer as the NIR‐stimuli gatekeeper. Curcumin, an inhibitor of Aβ aggregation, is loaded into the NP with high encapsulation efficiency. The 5‐mer β‐sheet breaker peptides LPFFD (Leu‐Pro‐Phe‐Phe‐Asp) having high binding affinity toward Aβ are further anchored onto the surface of polyethylene glycol‐lipid shell for active Aβ‐targeting. The resultant NPs exhibit good Aβ‐targeting ability and obvious photothermal dissociation effect together with Aβ aggregation‐dependent fluorescence detection capability. Upon NIR laser irradiation, entrapped curcumin can be effectively released from the unconsolidated NPs to enhance the anti‐amyloid activity. In vitro studies demonstrate that the NPs dramatically lower Aβ‐induced cytotoxicity of PC12 cells, and therefore show great potential for the application in AD treatment. [ABSTRACT FROM AUTHOR]

Conjugated polymers that support mixed (electronic and ionic) conduction are in demand for applications spanning from bioelectronics to energy harvesting and storage. To design polymer mixed conductors for high‐performance electrochemical devices, relationships between the chemical structure, charge transport, and morphology must be established. A polymer series bearing the same p‐type conjugated backbone with increasing percentage of hydrophilic, ethylene glycol side chains is synthesized, and their performance in aqueous electrolyte gated organic electrochemical transistors (OECTs) is studied. By using device physics principles and electrochemical analyses, a direct relationship is found between the OECT performance and the balanced mixed conduction. While hydrophilic side chains are required to facilitate ion transport—thus enabling OECT operation—swelling of the polymer is not de facto beneficial for balancing mixed conduction. It is shown that heterogeneous water uptake disrupts the electronic conductivity of the film, leading to OECTs with lower transconductance and slower response times. The combination of in situ electrochemical and structural techniques shown here contributes to the establishment of the structure–property relations necessary to improve the performance of polymer mixed conductors and subsequently of OECTs. [ABSTRACT FROM AUTHOR]

Conjugated polymers are essential for solution-processable organic opto-electronic devices. In contrast to the great efforts on developing new conjugated polymer backbones, research on developing side chains is rare. Herein, we report branched oligo(ethylene glycol) (OEG) as side chains of conjugated polymers. Compared with typical alkyl side chains, branched OEG side chains endowed the resulting conjugated polymers with a smaller π-π stacking distance, higher hole mobility, smaller optical band gap, higher dielectric constant, and larger surface energy. Moreover, the conjugated polymers with branched OEG side chains exhibited outstanding photovoltaic performance in polymer solar cells. A power conversion efficiency of 5.37 % with near-infrared photoresponse was demonstrated and the device performance could be insensitive to the active layer thickness. [ABSTRACT FROM AUTHOR]

The article cites reference of an article related to the synthesis of branched oligo side chains bearing diketopyrrolopyrrole-based conjugated polymers for photovoltaic devices by J. Liu and L. Wang et al which appeared in 2016 issue of journal.

We synthesize and systematicallystudy a series of conjugated polymerswith oligo(ethylene glycol) (OEG) or alkyl chain as the side chainand poly[2,7-fluorene-alt-5,5-(4,7-di-2-thienyl-2,1,3-benzothiadiazole)]as the polymer backbone. Replacing alkyl chain with OEG chain candecrease the π–π stacking distance of polymer backbonein thin film from 0.44 to 0.41 nm because OEG chain is more flexiblethan alkyl chain. As the result, the conjugated polymer with OEG sidechain exhibits higher hole mobility, red-shifted absorption spectrumin thin film and smaller bandgap than those of the conjugated polymerwith alkyl side chain. With the increase of the length of OEG sidechain, the resulting conjugated polymers exhibit unchanged π–πstacking distance and decreased hole mobility. Moreover, owing tothe large polarity of OEG chain, OEG side chain makes the conjugatedpolymer suitable for polymer solar cell (PSC) devices processed withpolar nonhalogenated solvent, methoxybenzene. A power conversion efficiencyof 4.04% is demonstrated with the resulting PSC devices. This workprovides the new insight into the effect of OEG side chain on conjugatedpolymer, which can be used in the molecular design of novel conjugatedpolymer materials with excellent optoelectronic device performance. [ABSTRACT FROM AUTHOR]

• An organic electrochemical transistor (OECT) based on an n-type polymer is developed. • The channel and gate are functionalized with the enzyme, glucose oxidase. • The OECT is integrated with a microfluidic system for real-time glucose monitoring. • Microfluidic integrated OECT sensor shows excellent signal-to-noise ratios and a detection limit of 1 nM. • Transistor configuration allows high signal-to-noise-ratios for metabolite sensing. The organic electrochemical transistor (OECT) can translate biochemical binding events between a recognition unit and its analyte into an electrical signal. We present an OECT comprising an n-type (electron transporting) conjugated polymer-based channel and lateral gate electrode functionalized with the enzyme, glucose oxidase. The device is integrated with a microfluidic system for real-time glucose monitoring in a flow-through manner. The n-type polymer has direct electrical communication with glucose oxidase, allowing glucose detection while surpassing hydrogen peroxide production. The microfluidic-integrated OECT shows superior features compared to its microfluidic-free counterpart, including higher current and transconductance values as well as improved signal-to-noise (SNR) ratios, which enhances the sensor sensitivity and its detection limit. Thanks to the low noise endowed by the integrated microfluidics, the gate current changes upon metabolite recognition could be resolved, revealing that while the relative changes in gate and drain currents are similar, the drain current output has a higher SNR. This is the first demonstration of the integration of a microfluidic system with an n-type accumulation mode OECT for real-time enzymatic metabolite detection. The microfluidic-integrated design provides new insights into the mechanisms leading to high sensor sensitivities, crucial for the development of portable and autonomous lab-on-a-chip technologies. [ABSTRACT FROM AUTHOR]