# Electrospun Nanofibers for Integrated Sensing, Storage, and Computing Applications
## 4 Applications of Electrospinning in Memory: Storage Electronics
In this case, metal atoms from the top electrode are ionized and drift towards the bottom electrode with a positive voltage given to the top electrode. When the magnitude of the applied voltage (V\({}_{\text{SET}}\)) reaches a certain level of value, a conductive filament made up of ions originating from the top electrode forms a bridge between the top and bottom electrodes, allowing current to flow freely through the device, and the resistance of the device drops, leading to the low resistance state (LRS). The negative bias mode exhibits a similar pattern of behavior concerning electrochemical breakage of the conductive filament and the corresponding state-changing voltage is termed as the RESET voltage [111]. In 2020, [PERSON] et al. innovatively came up with a memory device based on 1D functionalized multi-walled carbon nanotubes (f-MWCNTs)-TiO\({}_{2}\) composite electrospun nanofibers [112]. The device structure can be seen in Figure 16a. This three-layer random-access memory (RAM) showed obvious bipolar resistive switching (RS) behavior with clear evidence of the hysteresis loop (Figure 16b). The composite nanofiber-based device had excellent endurance and memory retention qualities, as demonstrated in Figure 16c,d respectively, which suggested that this memory device could easily toggle between LRS and HRS 500 times and could also keep these two states until 104 s without any significant degradation. Among other kinds of organic fibers, cellulose fibers with biodegradability, biocompatibility, and high tensile strength provided good charge transport pathways as well as support for the formation of the conductive filament of the bipolar resistive switching operation [113]. The \"Sandwich\" structure of Ag/cellulose fibers/Al memory device (Figure 16e) was then fabricated using the electrospinning technique and worked on low resistive switching voltage (\(\pm 1\) V) instead of an additional electroforming step (Figure 16f). It also had excellent endurance for \(6\times 10^{3}\) resistive switching cycles with a \(10\times\) memory window and great data retention capability for the \(3\times 10^{2}\) s without any observable degradation in the resistance states (Figure 16g,h). Moreover, cellulose-gelatine micro composite fibers (CGMFs) were fully used to realize the organic resistive switching devices and they are different from the previous ones in that test results proved that they had a pretty large current (\(-4\) mA) when the RAM was in the LRS due to the formation of the conductive filament and the low resistance value of the CGMFs composite at SET voltage [114] (Figure 16i). These exploratory studies present the fact that cellulose fiber-based memristive devices represent a sensible option for the organic non-volatile memory application. Figure 15: Memory materials or devices involving the electrospun nanofiber and their characteristics. (**a,b**) morphology of Nb\({}_{2}\)O\({}_{5}\) fiber and its corresponding memory device: (**a**) SEM images of Nb\({}_{2}\)O\({}_{5}\) nanofibers annealed at 700 \({}^{\circ}\)C for 1 h in air and the insert shows the nanofibers with higher magnification. (**b**) I–V characteristics of DLC/Nb\({}_{2}\)O\({}_{5}\) nanofiber/Pt junction recorded in a constant voltage mode with a 100 k\(\Omega\) ballast resistor. Reprinted with permission from Reference [107]. Copyright 2013 AIP Publishing. (**c,d**) electrospun Er:NKN nanofiber mat and its resistance switching characteristic: (**c**) I–V characteristics of the vertical Au/NKN(260\(\upmu\)m)/Pt/Si device and the inset image shows the I–V characteristics at low voltages in the planar Au/NKN(350\(\upmu\)m)/Au cell on Sitall substrate. (**d**) SEM images of as-spun Er:NKN fibers. Reprinted from Reference [108] Copyright 2017 IOP publishing. (**e–h**) perovskite decorated electrospun TiO\({}_{2}\) nanofibers and according memory applications: SEM image showing the morphology of (**e**) PVA-TiO\({}_{2}\) mat and (**f**) perovskite decorated PVA-TiO\({}_{2}\) mat.