Because of the dramatic increase in the all kinds of energy consumption, globally, the use of sustainable, renewable and green energy sources are gaining more attention in the last couple of decades. Solar energy, as one of the most important sources of sustainable energy, can be used to generate electricity through photovoltaic cells in order to prevent environmental pollutions, such as fossil fuels. To date, researchers, in various fields related to solar energy, have developed many projects for high-performance TCE, with optimum transmittance and conductivity, to use in photovoltaic cells. Recently, MNWN or MNFN-based structures were introduced as superior alternatives to electrodes such as ITO films. These lattice structures demonstrate favorable electrical, optical and mechanical properties due to their high aspect ratios of NWs and are, economically, more efficient compared to other structures. Modification in properties of CuNWs attracted a considerable attention among other NWs, such as silver, due to the low price and high conductivity. So far, many researches are conducted on the fabricated of CuNFs by electrospinning. In this study, by producing CuNFs as core-shell electrospinning, smooth and uniform crystalline nanofibers are produced that compete with other nanofibers in point of structure and morphology. The production of flexible CuNFs electrodes is performed in a three-stage process of: a) nanofibers production, b) calcinate, and c) transfer to a flexible substrate. In the first stage, different concentrations of Cucl2 are tested through core-shell electrospinning of Cucl2 and polyvinyl alcohol to achieve optimum properties of nanofibers, despite keeping constant the concentrations of 10% of w/v polymer solution. In this process, we compared the structure and the properties of produced nanofibers with CuCl2 concentrations of 25%, 30% and 35%. Also, under ambient temperature and humidity conditions, with a voltage of 18 kV and a working distance of 19 cm, in the periods of 6, 8 and 10 hours, electrospinning is performed to create networks with different traarency. In the second stage, thermal processes at 500 ° C, resulted in the formation of CuNWN by welding copper crystals, removing the polymer component and other impurities. The structure of the network has been examined by SEM, TEM, EDS, XRD and FTIR tests. In the last stage, to transfer the network to a flexible substrate PMMA polymer, two methods of dip coating and spin coating are implemented. In addition, the electrical, optical and mechanical properties of the produced structure are characterized with devices 4-point probe, spectrophotometer and Zwick. In this study, by maintaining the coherence between the copper crystals along the nanofibers and creating a uniform and smooth surface, completely crystalline nanofibers with high aspect ratio are produced. In these lattice structures, by reducing the contact resistance between nanofibers and, thus, reducing the sheet resistance, we can provide a better electrical conductivity. The average sheet resistance of all CuNFN samples, before and after transferring to the flexible substrate, is 58.30 ohm's and 4.50 MPa, respectively. The average traarency was 58.72% at 550 nm (visible spectra). The mechanical stability of the electrodes and the change in sheet resistance are also evaluated. On the other hand, CuNFN, at a concentration of 30%, show a better results compared other concentrations. Moreover, by increasing the concentration of cucl2 solution to an optimum level, the diameter of nanofibers increases, and due to the increase in the flow of electrons in the cross section of nanofibers, the sheet resistance decreases. As can be seen, the electrospinning time to creating more conductive paths, reduces the sheet resistance and the traarency of the samples. Generally, by increasing the voltage, the electric current increases. In order to determine the optimum results of electrodes, a number of samples were examined by the figure of merit.