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Item type:Publication, Access status: with files , Boosting OECT performance with PEGylated gold nanoparticles in hydrophobic channelsOrganic electrochemical transistors (OECTs) require organic mixed ion-electron conductors (OMIECs) (i.e., hydrophilic materials supporting electron and ion transportation) as active materials. However, high-performance OMIECs grafted with hydrophilic side chains are difficult to synthesize and purify, and often suffer from swelling during operation. In contrast, the synthetic pathways toward a broad range of hydrophobic polymeric semiconductors used in classic organic-field-effect transistors are well established, and several are even commercially available. Yet, these hydrophobic materials do not intrinsically support ionic transport, limiting their application in OECTs. Here, poly(ethyleneglycol) (PEG)-coated gold nanoparticles (AuNP) are incorporated into conventional hydrophobic polymeric semiconductors like poly-3-hexylthiophene (P3HT), improving not only ionic but also electronic transport. The hydrophilic AuNPs modify P3HT crystallite orientation, shorten lamellar and π–π distances, and create pathways for ion penetration, as evidenced by GIWAXS and AFM studies. With 5 wt% AuNP loading, OECTs achieve µC* of 98 F cm−1 V−1 s−1, comparable to hydrophilic materials. The strategy also works for other polymer systems, offering a facile method to utilize hydrophobic materials in OECTs and boost their performance.Publicationtype: Journal Article38 21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Stretchable semiconducting triblock copolymer blends : exploring the impact of block size(2024-03-06); ; ;Henke, Fritz ;Un Nisa, SabourStretchable semiconductors are vital for the development of emerging electronic biointerfaces. The physical blending of polymer semiconductors into elastomers presents a promising and straightforward method for creating stretchable films with high charge carrier mobilities. However, the understanding of the interplay between film morphology and the associated mechanical and electronic characteristics in blends is still limited. Especially, investigations into the blending behavior of more complex conjugated polymers, such as block copolymers, are lacking. In this study, we investigate the blending behavior of two semiconducting and stretchable triblock copolymers (TBCs). These copolymers comprise a middle block of poly(diketopyrrolopyrrole-co-thienothiophene) (PDPP-TT) and two outer blocks of poly(dimethylsiloxane) (PDMS) with different block-size ratios (85:15 and 40:60). The TBCs are blended into a crosslinked PDMS matrix. The resulting blends exhibit superior stretchability compared to the PDPP-TT homopolymer and retain their electric properties down to 40% PDPP-TT content in the blend. Increasing the PDMS block size inhibits macrophase separation and results in drastic decrease in charge carrier mobility, suggesting the necessity for macrophase separation within TBC/elastomer blends to maintain superior electric properties.Publicationtype: Journal Article27 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Rapid Detection of SARS-CoV-2 Antigens and Antibodies Using OFET Biosensors Based on a Soft and Stretchable Semiconducting PolymerIn the midst of the COVID-19 pandemic, adaptive solutions are needed to allow us to make fast decisions and take effective sanitation measures, e.g., the fast screening of large groups (employees, passengers, pupils, etc.). Although being reliable, most of the existing SARS-CoV-2 detection methods cannot be integrated into garments to be used on demand. Here, we report an organic field-effect transistor (OFET)-based biosensing device detecting of both SARS-CoV-2 antigens and anti-SARS-CoV-2 antibodies in less than 20 min. The biosensor was produced by functionalizing an intrinsically stretchable and semiconducting triblock copolymer (TBC) film either with the anti-S1 protein antibodies (S1 Abs) or receptor-binding domain (RBD) of the S1 protein, targeting CoV-2-specific RBDs and anti-S1 Abs, respectively. The obtained sensing platform is easy to realize due to the straightforward fabrication of the TBC film and the utilization of the reliable physical adsorption technique for the molecular immobilization. The device demonstrates a high sensitivity of about 19%/dec and a limit of detection (LOD) of 0.36 fg/mL for anti-SARS-Cov-2 antibodies and, at the same time, a sensitivity of 32%/dec and a LOD of 76.61 pg/mL for the virus antigen detection. The TBC used as active layer is soft, has a low modulus of 24 MPa, and can be stretched up to 90% with no crack formation of the film. The TBC is compatible with roll-to-roll printing, potentially enabling the fabrication of low-cost wearable or on-skin diagnostic platforms aiming at point-of-care concepts.Publicationtype: Journal Article24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Synthesis of linear unsubstituted poly(4,4′-triphenylamine) via Suzuki-Miyaura coupling of an asymmetric AB monomer(2022-06-15); ; ; ; Polytriarylamines (PTAAs) are amorphous polymers that can be reversibly oxidized to generate stable radical cations. Despite exhibiting a low charge carrier mobility, PTAAs are widely used as hole-transporting layers in perovskite solar cells due to their excellent stability under ambient conditions. The highest occupied molecular orbital (HOMO) energy levels of PTAA are generally in the range of −5.1 to −5.2 eV, and therefore slightly too high for an optimal alignment with perovskites. Most linear PTAAs carry two or three methyl substituents per repeating unit. While these prevent crosslinking of chains and thus provide reaction control, the electron-donating substituents raise the energy level of the HOMO. Unsubstituted PTAA on the other hand is usually obtained crosslinked via oxidative polymerization, while nickel-catalyzed Grignard polycondensation leads to inclusion of impurities. We report the synthesis of linear unsubstituted PTAA using Suzuki-Miyaura coupling of a novel asymmetric monomer, 4-((4-bromophenyl)(phenyl)amino)phenyl)boronic acid M1. Based on matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) and 1H NMR analysis, we can conclude that the hydrogen-terminated linear polymer is obtained. The determined HOMO energy level of −5.47 eV is a favorable match for many perovskite systems.Publicationtype: Journal Article16