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Wu, Siying

University of British Columbia

Yarns, the building blocks of textile-based wearable electronics, present integration challenges with electronic components, due to their curved linear nature and the inherent brittleness of various conductive/semiconductive materials. Addressing these challenges, this study focuses on structuring electronic components into nanofibers, aligning with the flexible and soft nature of yarns. In this work, to develop smart yarns responsive to mechanical and optical stimuli, flexible composite nanofibers, integrating inorganic metal halide perovskites (MHPs) with polymer nanofibers, were studied. These optimized nanofibers can serve as functional components in yarns, enabling piezoelectric responses and photo-sensing capabilities for mechano-electrical and opto-electrical conversions, respectively. Piezoelectric nanogenerator (PENG) yarns, composed of in-situ synthesized CsPbI₂Br in polyvinylidene difluoride (PVDF) nanofibers, achieved an open-circuit voltage of 8.4 V and a short-circuit current of 1.9 μA. After 3 months in an ambient environment without encapsulations, the PENG yarn can generate consistent voltage output in response to 192,000 cycles of mechanical compression. Moreover, these PENG yarns exhibit deformability for various textile integrations, showcasing their potential for on-body energy harvesting and motion sensing. Photo-sensing yarns, assembled with annealing-free electrospun CsPbI₂Br-polyvinyl acetate (PVAc) nanofibers, generated a photovoltage of 180 mV and a current density of 17 mA/cm² in response to 532 nm pulsed laser with an excellent ambient stability of 16 days. To further improve the overall performance and reduce the toxicity, up to 27 % of lead ions were replaced with silver ions. Photo-sensing yarns with silver-substituted CsPbI₂Br-PVAc nanofibers achieved an enhanced photovoltage of 504 mV, current density of 84 mA/cm², and better ambient stability of 60 days, due to improved crystalline structures. In summary, this study presents inorganic MHP-polymer nanofibers and their applications for smart yarns responsive towards mechanical and optical stimuli. This work charts a course for further explorations into the electrospinning of MHPs and their integration into textiles.

Text

2025-01-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87203

Materials Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/