Abstract
Stretchable polymer semiconductors (PSCs) have seen great advancements alongside the development of soft electronics. But it remains a challenge to simultaneously achieve high charge carrier mobility and stretchability. Herein, we report the finding that stretchable PSC thin films (<100-nm-thick) with high stretchability tend to exhibit multi-modal energy dissipation mechanisms and have a large relative stretchability (rS) defined by the ratio of the entropic energy dissipation to the enthalpic energy dissipation under strain. They effectively recovered the original molecular ordering, as well as electrical performance, after strain was released. The highest rS value with a model polymer (P4) exhibited an average charge carrier mobility of 0.2 cm2V−1s−1 under 100% biaxial strain, while PSCs with low rS values showed irreversible morphology changes and rapid degradation of electrical performance under strain. These results suggest rS can be used as a parameter to compare the reliability and reversibility of stretchable PSC thin films.
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Introduction
Polymer semiconductors (PSCs) have been developed for use in next-generation soft electronics (e.g., flexible, bendable, or stretchable devices)1,60 and a sin(omega) correction was applied for the data analyses. Agilent Cary 6000i UV/Vis/NIR spectroscopy was used to measure the UV-vis absorption spectra. A polarizer crystal was equipped to measure the absorption intensity with the polarization parallel (A//) and perpendicular (A⊥) to the stretching directions. The dichroic ratio (DR) was determined by A///A⊥ for analyzing polymer chain alignment under strain. The rS value is defined as the ratio of DR/rDoC at various strains, the DR values were averaged from at least 3 samples from 3 different batches and the rDoC values were averaged from at least 3 samples from 3 different batches for each polymer under a specific strain condition (i.e., 0, 50, or 100% strain). All the FET devices were probed using a Keithley 4200 semiconductor parameter analyzer (Keithley Instruments Inc.) in ambient at room temperature
Data availability
The authors declare that all data supporting the findings of this study are available within the article and its Supplementary Information files or from the corresponding author upon request.
References
Root, S. E., Savagatrup, S., Printz, A. D., Rodriquez, D. & Lipomi, D. J. Mechanical properties of organic semiconductors for stretchable, highly flexible, and mechanically robust electronics. Chem. Rev. 117, 6467–6499 (2017).
Ma, R., Chou, S. Y., **e, Y. & Pei, Q. Morphological/nanostructural control toward intrinsically stretchable organic electronics. Chem. Soc. Rev. 48, 1741–1786 (2019).
Fratini, S., Nikolka, M., Salleo, A., Schweicher, G. & Sirringhaus, H. Charge transport in high-mobility conjugated polymers and molecular semiconductors. Nat. Rev. Mater. 19, 491–502 (2020).
Printz, A. D. & Lipomi, D. J. Competition between deformability and charge transport in semiconducting polymers for flexible and stretchable electronics. Appl. Phys. Rev. 3, 021302 (2016).
Wang, G. J. N., Gasperini, A. & Bao, Z. Stretchable polymer semiconductors for plastic electronics. Adv. Electronic Mater. 4, 1700429 (2018).
Qian, Y. et al. Stretchable organic semiconductor devices. Adv. Mater. 28, 9243–9265 (2016).
Thiyagarajan, K. & Jeong, U. Strategies for stretchable polymer semiconductor layers. MRS Bulletin 42, 98–102 (2017).
**no, H. et al. Stretchable and waterproof elastomer-coated organic photovoltaics for washable electronic textile applications. Nat. Energy 2, 780–785 (2017).
Zhang, G. et al. Robust and stretchable polymer semiconducting networks: from film microstructure to macroscopic device performance. Chem. Mater. 31, 6530–6539 (2019).
Yin, H., Zhu, Y., Youssef, K., Yu, Z. & Pei, Q. Structures and materials in stretchable electroluminescent devices. Adv. Mater. 33, 2106184 (2021).
Wang, B. et al. Foundry-compatible high-resolution patterning of vertically phase-separated semiconducting films for ultraflexible organic electronics. Nat. Commun. 12, 4937 (2021).
Zheng, Y. Q. et al. Monolithic optical microlithography of high-density elastic circuits. Science 373, 88–94 (2021).
Matsuhisa, N. et al. High-frequency and intrinsically stretchable polymer diodes. Nature 600, 246–252 (2021).
Roth, B. et al. Mechanical properties of a library of low-band-gap polymers. Chem. Mater. 28, 2363–2373 (2016).
Lu, C. et al. Effects of molecular structure and packing order on the stretchability of semicrystalline conjugated poly (tetrathienoacene‐diketopyrrolopyrrole) polymers. Adv. Electronic Mater. 3, 1600311 (2017).
Oh, J. Y. et al. Intrinsically stretchable and healable semiconducting polymer for organic transistors. Nature 539, 411–415 (2016).
Zheng, Y. et al. An intrinsically stretchable high‐performance polymer semiconductor with low crystallinity. Adv. Funct. Mater. 29, 1905340 (2019).
Wu, H.-C. et al. Isoindigo-based semiconducting polymers using carbosilane side chains for high performance stretchable field-effect transistors. Macromolecules 49, 8540–8548 (2016).
Mun, J. et al. A design strategy for high mobility stretchable polymer semiconductors. Nat. Commun. 12, 3572 (2021).
Wang, G. J. N. et al. Inducing elasticity through oligo‐siloxane crosslinks for intrinsically stretchable semiconducting polymers. Adv. Funct. Mater. 26, 7254–7262 (2016).
Wang, G. J. N. et al. Tuning the cross-linker crystallinity of a stretchable polymer semiconductor. Chem. Mater. 31, 6465–6475 (2018).
Zheng, Y. et al. A molecular design approach towards elastic and multifunctional polymer electronics. Nat. Commun. 12, 5701 (2021).
Chen, S. et al. Highly flexible and efficient all‐polymer solar cells with high‐viscosity processing polymer additive toward potential of stretchable devices. Angew. Chem. In. Ed. 57, 13277–13282 (2018).
Mun, J. et al. Conjugated carbon cyclic nanorings as additives for intrinsically stretchable semiconducting polymers. Adv. Mater. 31, 1903912 (2019).
Xu, J. et al. Tuning conjugated polymer chain packing for stretchable semiconductors. Adv. Mater. 33, 2104747 (2022).
Scott, J. I. et al. Significantly increasing the ductility of high performance polymer semiconductors through polymer blending. ACS Appl. Mater. Interfaces 8, 14037–14045 (2016).
Shin, M. et al. Highly stretchable polymer transistors consisting entirely of stretchable device components. Adv. Mater. 26, 3706–3711 (2014).
Kim, H. J., Thukral, A., Sharma, S. & Yu, C. Biaxially stretchable fully elastic transistors based on rubbery semiconductor nanocomposites. Adv. Mater. Tech. 3, 1800043 (2018).
Zhang, G. et al. Versatile interpenetrating polymer network approach to robust stretchable electronic devices. Chem. Mater. 29, 7645–7652 (2017).
Xu, J. et al. Highly stretchable polymer semiconductor films through the nanoconfinement effect. Science 355, 59–64 (2017).
Xu, J. et al. Multi-scale ordering in highly stretchable polymer semiconducting films. Nat. Mater. 18, 594–601 (2019).
Wen, H.-F. et al. Soft poly (butyl acrylate) side chains toward intrinsically stretchable polymeric semiconductors for field-effect transistor applications. Macromolecules 50, 4982–4992 (2017).
Sugiyama, F. et al. Stretchable and degradable semiconducting block copolymers. Macromolecules 51, 5944–5949 (2018).
Wang, J.-T. et al. Stretchable conjugated rod–coil poly (3-hexylthiophene)-block-poly (butyl acrylate) thin films for field effect transistor applications. Macromolecules 50, 1442–1452 (2017).
Choi, J. et al. Importance of critical molecular weight of semicrystalline n-type polymers for mechanically robust, efficient electroactive thin films. Chem. Mater. 31, 3163–3173 (2019).
Pei, D. et al. Impact of molecular weight on the mechanical and electrical properties of a high-mobility diketopyrrolopyrrole-based conjugated polymer. Macromolecules 53, 4490–4500 (2020).
Koch, F. P. V. et al. The impact of molecular weight on microstructure and charge transport in semicrystalline polymer semiconductors–poly (3-hexylthiophene), a model study. Prog. Polym. Sci. 38, 1978–1989 (2013).
Chen, J.-Y. et al. Electrospinning-induced elastomeric properties of conjugated polymers for extremely stretchable nanofibers and rubbery optoelectronics. J. Mater. Chem. C 8, 873–882 (2019).
Lin, L. et al. Towards tunable sensitivity of electrical property to strain for conductive polymer composites based on thermoplastic elastomer. ACS Appl. Mater. Interfaces 5, 5815–5824 (2013).
Niu, W. et al. Synthesis and properties of soluble fused thiophene diketopyrrolopyrrole-based polymers with tunable molecular weight. Macromolecules 51, 9422–9429 (2018).
Dechnarong, N. et al. Microdomain structure change and macroscopic mechanical response of styrenic triblock copolymer under cyclic uniaxial and biaxial stretching modes. Polym. J. 53, 703–712 (2021).
Rodriquez, D. et al. Comparison of methods for determining the mechanical properties of semiconducting polymer films for stretchable electronics. ACS Appl. Mater. Interfaces 9, 8855–8862 (2017).
Noriega, R. et al. A general relationship between disorder, aggregation and charge transport in conjugated polymers. Nat. Mater. 12, 1038–1044 (2013).
Chen, J. et al. Effect of molecular chain architecture on dynamics of polymer thin films measured by the Ac-chip calorimeter. Macromolecules 47, 3497–3501 (2014).
Zhang, W., Milner, S. T. & Gomez, E. D. Nematic order imposes molecular weight effect on charge transport in conjugated polymers. ACS Central Sci. 4, 413–421 (2018).
O’Connor, B. et al. Correlations between mechanical and electrical properties of polythiophenes. ACS Nano 4, 7538–7544 (2010).
Printz, A. D., Zaretski, A. V., Savagatrup, S., Chiang, A. S. C. & Lipomi, D. J. Yield point of semiconducting polymer films on stretchable substrates determined by onset of buckling. ACS Appl. Mater. Interfaces 7, 23257–23264 (2015).
Flory, P. J. & Yoon, D. Y. Molecular morphology in semicrystalline polymers. Nature 272, 226–229 (1978).
Men, Y., Rieger, J. & Strobl, G. Role of the entangled amorphous network in tensile deformation of semicrystalline polymers. Phys. Rev. Lett. 91, 095502 (2003).
Jiang, Z. et al. Structural evolution of tensile-deformed high-density polyethylene during annealing: scanning synchrotron small-angle X-ray scattering study. Macromolecules 40, 7263–7269 (2007).
Jabbari-Farouji, S. et al. Plastic deformation mechanisms of semicrystalline and amorphous polymers. ACS Macro Lett. 4, 147–150 (2015).
O’Connor, B. T. et al. Morphological origin of charge transport anisotropy in aligned polythiophene thin films. Adv. Funct. Mater. 24, 3422–3431 (2014).
Nikzad, S. et al. Effect of extensional flow on the evaporative assembly of a donor–acceptor semiconducting polymer. ACS Appl. Electronic Mater. 1, 2445–2454 (2019).
Dechnarong, N. et al. In situ synchrotron radiation X-ray scattering investigation of a microphase-separated structure of thermoplastic elastomers under uniaxial and equi-biaxial deformation modes. Macromolecules 53, 8901–8909 (2020).
Hiss, R. et al. Network stretching, slip processes, and fragmentation of crystallites during uniaxial drawing of polyethylene and related copolymers. A comparative study. Macromolecules 32, 4390–4403 (1999).
Gargi, D. et al. Charge transport in highly face-on poly (3-hexylthiophene) films. J. Phys. Chem. C 117, 17421–17428 (2013).
Heinrich, G., Straube, E., & Helmis, G. Rubber elasticity of polymer networks: Theories. In Polymer physics 33–87 (Springer, Berlin, Heidelberg, 1988).
Schroeder, B. C. et al. Non-conjugated flexible linkers in semiconducting polymers: A pathway to improved processability without compromising device performance. Adv. Electronic. Mater. 2, 1600104 (2016).
Savagatrup, S. et al. Mechanical properties of conjugated polymers and polymer-fullerene composites as a function of molecular structure. Adv. Funct. Mater. 24, 1169–1181 (2014).
Baker, J. L. et al. Quantification of thin film crystallographic orientation using X-ray diffraction with an area detector. Langmuir 26, 9146–9151 (2010).
Acknowledgements
This work is supported by the Air Force Office of Scientific Research under award numbers FA9550-18-1-0143 (17RT0917) and FA9550-21-1-0413 (21RT0491). J.X. acknowledges the Center for Nanoscale Materials, supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. N.M. acknowledges funding support from an overseas fellowship from the Japan Society for the Promotion of Science (JSPS). C.L. acknowledges support from the National Science Foundation through grant CMMI-1911836. This work was partially performed at the Stanford Nano Shared Facilities (SNSF), supported by the National Science Foundation under award ECCS-1542152. GIXD experiments were carried out at the Stanford Synchrotron Radiation Laboratory (SSRL), a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. The authors acknowledge Bart Johnson at SSRL for supporting GIXD experiment and Brandon Clark for hel** thin film characterizations.
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H.-C.W and S.N. contributed equally to this work. H.-C.W., M.H., and Z.B. conceived and designed the experiments; H.-C.W., S.N., C.Z., N.M., J.X., and Y.-Q.Z. fabricated and characterized thin films and transistor devices; H.-C.W., S.N., and H.Y. did the GIXD characterizations; Y.L., W.N., J.R.M. and M.H. designed and synthesized the conjugated polymers; P.K.A., R.R., and C.L. carried out the simulation of stretched films; H.Y. and M.F.T. advised on the discussion of morphological results; H.-C.W. organized the data and wrote the first draft of the manuscript. All authors reviewed and commented on the manuscript. Z.B. directed the project.
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Wu, HC., Nikzad, S., Zhu, C. et al. Highly stretchable polymer semiconductor thin films with multi-modal energy dissipation and high relative stretchability. Nat Commun 14, 8382 (2023). https://doi.org/10.1038/s41467-023-44099-w
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DOI: https://doi.org/10.1038/s41467-023-44099-w
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