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1. Tunable Solid‐State Properties and Anisotropic Charge Mobility in Hydrogen‐Bonded Diketopyrrolopyrrole Polymers via Automated Device Fabrication and Characterization

   https://doi.org/10.1002/adfm.202403612  

   Nyayachavadi, Audithya; Wang, Chengshi; Vriza, Aikaterini; Wang, Yunfei; Ma, Guorong; Mooney, Madison; Mason, Gage T; Hu, Anita; Liu, Yuzi; Gu, Xiaodan; et al (October 2024, Advanced Functional Materials)

   Abstract The optoelectronic properties of semiconducting polymers and device performance rely on a delicate interplay of design and processing conditions. However, screening and optimizing the relationships between these parameters for reliably fabricating organic electronics can be an arduous task requiring significant time and resources. To overcome this challenge, Polybot is developed—a robotic platform within a self‐driving lab that can efficiently produce organic field‐effect transistors (OFETs) from various semiconducting polymers via high‐throughput blade coating deposition. Polybot not only handles the fabrication process but also can conduct characterization tests on the devices and autonomously analyze the data gathered, thus facilitating the rapid acquisition of data on a large scale. This work leverages the capabilities of this platform to investigate the fabrication of OFETs using hydrogen bonding‐containing semiconducting polymers. Through high‐throughput fabrication and characterization, various data trends are analyzed, and large extents of anisotropic charge mobility are observed in devices. The materials are thoroughly characterized to understand the role of processing conditions in solid state and electronic properties of these organic semiconductors. The findings demonstrate the effectiveness of automated fabrication and characterization platforms in uncovering novel structure–property relationships, facilitating refinement of rational chemical design, and processing conditions, ultimately leading to new semiconducting materials. 

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2. Effect of polar side chains on neutral and p-doped polythiophene

   https://doi.org/10.1039/D0TC04290K  

   Finn, Peter A.; Jacobs, Ian E.; Armitage, John; Wu, Ruiheng; Paulsen, Bryan D.; Freeley, Mark; Palma, Matteo; Rivnay, Jonathan; Sirringhaus, Henning; Nielsen, Christian B. (November 2020, Journal of Materials Chemistry C)

   null (Ed.)

   Incorporation of polar side chains on organic semiconducting materials have been used recently in thermoelectric materials to increase dopant:semiconductor miscibility and stability to further increase the performance and durability of devices. However, investigations into how polar side chains can affect the structure and energetics of polythiophenes compared to non-polar alkyl side chains are usually carried out using materials with no common morphological structure. Within this work we systematically investigate the increase in polar side chain content on poly(3-hexylthiophene) (P3HT) and how the optical, electrochemical, and structural properties are affected. We find a decreasing degree of aggregation with increasing polar side chain content leading to lower charge carrier mobilities. Upon doping with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), we find that the electrical conductivity is reduced when incorporating the polar side chain and no stabilising effect is demonstrated when annealing the doped thin films at raised temperatures. This study emphasises that polar functionalities do not always increase dopant:semiconductor interactions and can harm desirable structural and electrical characteristics, and therefore should be incorporated into organic semiconductors with caution. 

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3. Machine learning of the architecture–property relationship in graft polymers

   https://doi.org/10.1039/D5CP01334H  

   Bigting, Kevin V; Carden, Jordan J; Nag, Shubhadeep; Lawrence, Jimmy; Su, Yen-Fang; An, Yaxin (June 2025, Physical Chemistry Chemical Physics)

   Graft polymers are promising in energy and biomedical applications. However, the diverse architectures make it challenging to establish their structure–property relationships. We systematically investigate how backbone and side-chain architectures influence four key properties: glass transition temperature (Tg), self-diffusion coefficient (D), radius of gyration (Rg), and packing density (ρ). Using molecular dynamics simulations, we analyze a dataset of 500 graft polymers with randomly positioned side chains. Tg and D exhibit decoupled relationships due to the distinct topological effects. Furthermore, we develop dense neural networks (DNNs) and convolutional neural networks (CNNs) to pave the way to polymer design with desired properties. 

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4. Material properties and applications of mechanically interlocked polymers

   https://doi.org/10.1038/s41578-021-00278-z  

   Hart, Laura F.; Hertzog, Jerald E.; Rauscher, Phillip M.; Rawe, Benjamin W.; Tranquilli, Marissa M.; Rowan, Stuart J. (January 2021, Nature Reviews Materials)

   null (Ed.)

   Mechanically interlocked polymers (MIPs), polymer architectures that incorporate the mechanical bond, have seen a dramatic growth in interest over the last decade or so. Of particular interest in these architectures are the high mobility and conformational freedom of the interlocked components, which can give rise to unique property profiles. Over the years the research advances, from the chemistry, physics, material science and engineering fields, has started to build an understanding of how incorporating mechanical bonds into a polymer structure impacts its properties. This review focuses on summarizing the state-of-the-art understanding of the structure-property relationships in these materials and an outlook toward their applications, specifically focusing on four main classes of MIPs, polyrotaxanes, slide-ring gels, daisy-chain polymers and polycatenanes. 

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5. Dynamic self-stabilization in the electronic and nanomechanical properties of an organic polymer semiconductor

   https://doi.org/10.1038/s41467-022-30801-x  

   Dobryden, Illia; Korolkov, Vladimir V.; Lemaur, Vincent; Waldrip, Matthew; Un, Hio-Ieng; Simatos, Dimitrios; Spalek, Leszek J.; Jurchescu, Oana D.; Olivier, Yoann; Claesson, Per M.; et al (December 2022, Nature Communications)

   Abstract The field of organic electronics has profited from the discovery of new conjugated semiconducting polymers that have molecular backbones which exhibit resilience to conformational fluctuations, accompanied by charge carrier mobilities that routinely cross the 1 cm 2 /Vs benchmark. One such polymer is indacenodithiophene-co-benzothiadiazole. Previously understood to be lacking in microstructural order, we show here direct evidence of nanosized domains of high order in its thin films. We also demonstrate that its device-based high-performance electrical and thermoelectric properties are not intrinsic but undergo rapid stabilization following a burst of ambient air exposure. The polymer’s nanomechanical properties equilibrate on longer timescales owing to an orthogonal mechanism; the gradual sweating-out of residual low molecular weight solvent molecules from its surface. We snapshot the quasistatic temporal evolution of the electrical, thermoelectric and nanomechanical properties of this prototypical organic semiconductor and investigate the subtleties which play on competing timescales. Our study documents the untold and often overlooked story of a polymer device’s dynamic evolution toward stability. 

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