# Electrospun Nanofibers for Integrated Sensing, Storage, and Computing Applications
## 6 Artificial Synapses and Other Electronic Devices Prepared by Electrospinning
It was also found that EPSC could not decay back to the original current value following intense stimulation in a brief amount of time, demonstrating the long-term synaptic plasticity of the device. Low power consumption of 0.44 pJ demonstrated its potential applications for energy-efficient artificial synapses for sophisticated neuromorphic networks. Simultaneously, electrospun nanofibers also give full play to their advantages for various electronic devices. For instance, photoelectric detectors could have sensitive photoresponse and incredible electrical performance when they are fabricated by 1D electrospun nanofibers with a large specific area and increased photosensitive area of the materials. A novel UV photodetector with a ZnO nanofiber array was realized in this way. Aligned pure n-type ZnO nanofibers and Ag-doped p-type ZnO nanofibers formed a crossed array that functioned as homojunction to change the material conductivity under optical radiation and the device was fully transparent on the quartz substrate [131] (Figure 22a,b). The performance of this photodetector was considerably improved to have a high on/off ratio of 2.5 \(\times\) 10\({}^{4}\) together with a responsivity of 1 \(\times\) 10\({}^{3}\)\(\upmu\)m W\({}^{-1}\) in the p-n junction form under zero bias voltage. (Figure 22c,d). Electrospun nanofibers were able to produce a heterojunction that acted as photodetector as well and the obtained SnO\({}_{2}\)/NiO nanofiber array (Figure 22e) was proven to have a high detectivity of 2.33 \(\times\) 10\({}^{13}\) Jones and responsivity up to 8.67 A W\({}^{-1}\), as exhibited in Figure 22f, outperforming most of the state-of-art SnO\({}_{2}\)-based photodetectors [132]. Besides, electrospinninging also brought new possibilities to the portable and wearable power source as conductive electrodes. A uniform, free-standing,  
Figure 20: Solid-ion gated OFETs with PEO/PQT12 nanofiber channel and its electrical properties: (**a**) Image of practical structure of the FET. (**b**) Typical EPSC behavior of the transistors triggered by a presynaptic spike (\(-\)1 V, 0.1 s). (**c**) Typical PPF behavior of the transistors triggered by a presynaptic spike (\(-\)1 V, 0.1 s on, 0.2 s off). (**d**) Exploration of the energy consumption of the transistors at varied spike intensities and read voltages. (**e**) The lowest-energy EPSC behavior of the device is triggered by \(-\)0.5 mV and recorded by \(-\)0.1 mV and the minimum energy consumption is about 3.9 fJ. (**f**) EPSC signals in response to ten presynaptic pulses of different frequencies. Reprinted with permission from Reference [128]. Copyright 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Sn-based (Sn@CFC) electrode was fabricated by the electrospinningning technique to serve in the sodium-ion batteries (SIBs) for large-scale energy storage instead of conventional lithium-ion batteries (LIBs) (Figure 22g) [133]. Ultra-small Sn nanoparticles were decorated around the three-dimensional carbon nanofibers, leading to the shortened pathway for sodium ions and electrons, mitigated volume expansion, and improved electrical conductivity. This fiber-based electrode showed high reversible areal capacity (1.68 mA h cm\({}^{-2}\)) and a long-life cycle of 1000 cycles with above 80% capacity retention in Figure 22h,i. Apart from electrode materials of SIBs and LIBs, electrospun fiber-based mats have gradually extended their applications to many other energy storage devices, such as supercapacitors, Li-S batteries, Li-CO\({}_{2}\) batteries, Li-O\({}_{2}\) batteries, and so on [134, 135, 136, 137, 138, 139]. These studies demonstrated the fact that nanomaterials produced by electrospinningning have become a potential option for high-efficiency photodetectors and electrodes, and inspired a new way to design other optoelectronic devices with various 1D semiconductor materials. Figure 21: Examples of transistor-based artificial synapses prepared by electrospinningning.