Ultrahigh Responsivity and Robust Semiconducting Fiber Enabled by Molecular Soldering‐Governed Defect Engineering for Smart Textile Optoelectronics

Abstract Semiconducting fibers (SCFs) are of significant interest to design next‐generation wearable and comfortable optoelectronics that seamlessly integrate with textiles. However, the practical applications of current SCFs are always limited by poor optoelectronic performance and low mechanical robustness caused by uncontrollable multiscale structural defects. Herein, a versatile in situ molecular soldering‐governed defect engineering strategy is proposed to construct ultrahigh responsivity and robust wet‐spun MoS 2 SCFs, by using a π‐conjugated dithiolated molecule to simultaneously patch microscale sulfur vacancies within MoS 2 nanosheets, diminish mesoscale interlayer voids/wrinkles, promote macroscale orientation, build long‐range photoelectron percolation bridges, and provide n‐doping effect. The derived MoS 2 SCFs exhibit over two orders of magnitude higher responsivity (144.3 A W −1 ) than previously reported fiber photodetectors, 37.3‐fold faster photoresponse speed (52 ms) than pristine counterpart, and remarkable bending robustness (retain 94.2% of the initial photocurrent after 50 000 bending‐flattening cycles). Such superior robustness and photodetection capacity of MoS 2 SCFs further enable large‐scale weaving of reliable smart textile optoelectronic systems, such as direction‐identifiable wireless light alarming system, modularized mechano‐optical communication system, and indoor light‐controlled IoT system. This work offers a universal strategy for the scalable production of mechanically robust and high‐performance SCFs, opening up exciting possibilities for large‐scale integration of wearable optoelectronics.