The immobilization of enzymes is always an important factor that limits the development of biosensors. Especially for optical fiber biosensors, it is usually necessary to modify the surface of the optical fiber through complex chemical reactions so that enzymes can be attached to the surface firmly. In this article, we used the enzyme immobilization method of electrospinning on the optical fiber sensor for the first time. The detection of glucose was realized by using electrospinning to fix a layer of crosslinked polyvinyl alcohol nanofibers that encapsulated glucose oxidase on the surface of the side-polished D-shape optical fiber. The experimental results show that the sensitivity of the designed sensor is 1.875dB/(mg/ml) when the glucose concentration range is 0mg/ml~4mg/ml. The electrospinning method of optical fiber enzyme immobilization is very promising and can be used to rapidly develop more other types of optical fiber biosensors.

In recent years, owing to the continuous development of polymer nanofiber manufacturing technology, various nanofibers with different structural characteristics have emerged, allowing their application in the field of sensing to continually expand. Integrating polymer nanofibers with optical sensors takes advantage of the high sensitivity, fast response, and strong immunity to electromagnetic interference of optical sensors, enabling widespread use in biomedical science, environmental monitoring, food safety, and other fields. This paper summarizes the research progress of polymer nanofibers in optical sensors, classifies and analyzes polymer nanofiber optical sensors according to different functions (fluorescence, Raman, polarization, surface plasmon resonance, and photoelectrochemistry), and introduces the principles, structures, and properties of each type of sensor and application examples in different fields. This paper also looks forward to the future development directions and challenges of polymer nanofiber optical sensors, and provides a reference for in-depth research of sensors and industrial applications of polymer nanofibers.

Ultraviolet-visible-near infrared broadband photodetectors have significant prospects in many fields such as image sensing, communication, chemical sensing, and day and nighttime surveillance. Hybrid one-dimensional (1D) and zero-dimensional (0D) materials are attractive for broadband-responsive photodetectors since its unique charges transfer characteristics and facile fabrication processes. Herein, a Si/ZnO nanowires/Ge quantum dots photodetector has been constructed via processes that combined electrospinning and spin-coating methods. A broadband response behavior from ultraviolet to near-infrared (from 250 to 1550 nm) is observed. The responsivity of the hybrid structure increases around three times from 550 to 1100 nm compared with the pure Si photodetector. Moreover, when the photodetector is illuminated by a light source exceeding 1100 nm, such as 1310 and 1550 nm, there is also a significant photoresponse. Additionally, the ZnO NWs/Ge quantum dots heterostructure is expected to be used in flexible substrates, which benefits from electrospinning and spin-coating processes. The strategy that combines 1D ZnO NWs and 0D solution-processed Ge QDs nanostructures may open a new avenue for flexible and broadband photodetector.

With the in-depth study of solid-state batteries (SSBs), various in situ and ex situ characterization technologies have been widely used to study them. The performance and reliability of SSBs are limited by the formation and evolution of lithium dendrites at the interfaces between solid electrodes and solid electrolytes. We propose a new method based on optical coherence tomography (OCT) for in situ characterization of the internal state of solid-state batteries. OCT is a low-loss, high-resolution, non-invasive imaging technique that can provide real-time monitoring of cross-sectional images of internal structures of SSBs. The morphology, growth, and evolution of lithium dendrites at different stages of cycling under various conditions can be visualized and quantified by OCT. Furthermore, we validate and correlate the OCT results with scanning electron microscopy (SEM) and XPS, proving the accuracy and effectiveness of the OCT characterization method. We reveal the interfacial phenomena and challenges in SSBs and demonstrate the feasibility and advantages of OCT as a powerful tool for in situ and operando imaging of battery interfaces. This study provides new insights into the mechanisms and factors that affect SSB performance, safety, and lifetime, and suggests possible solutions for improvement and application in the field of applied energy.