## 3 Results and Discussion
First, we inspected their appearance to verify that the silver-nanowire-embedded flexible electrodes with the NOAs were well constructed. As can be seen in the inset of Figure 4a, the flexible electrodes looked clearer than those constructed with SU8 because the NOAs are more transparent. Additionally, no tears or defects can be seen. Thus, we confirmed the successful fabrication of silver-nanowire-embedded transparent electrodes with the NOA series polymers. After preparing the electrodes, we measured the thicknesses at their center and edge, which are shown in Figure 4b,c, respectively. Because the NOAs have a higher viscosity than SU8 (the highest viscosity of SU8 was 1500 cps, whereas NOA63 has a viscosity of 2500 cps), we expected the film to be thicker using NOAs. In fact, the maximum thickness at the center was 80 \(\upmu\)m with SU8 and 180 \(\upmu\)m with NOA63. However, the trend of the thickness for different viscosities and spinning speeds was similar. The flexible electrodes became thinner with increasing spin speed, whereas high-viscosity NOA solutions induced thicker electrodes. Additionally, the edge was thicker than the center. However, it was impossible to fabricate silver-nanowire-embedded transparent electrodes at high spinning speed using NOA73, i.e., that with the lowest viscosity, because the layers were excessively thin and could not be delaminated from the PMMA-coated substrate. Figure 3: **(a)** Thickness difference and **(b)** thickness ratio in silver-nanowire-embedded flexible electrodes in different SU8. The thickness difference was calculated by subtracting the thickness at the edge from that at the center. The thickness ratio was obtained by dividing them by the thickness at the edge. We then calculated the thickness difference and ratio between the center and edge. Figure 5a,b shows the thickness difference and ratio based on the thickness at the edge. Similar to SU8, the thickness difference decreased for increasing spinning speed in all films except for the NOA63 one. We speculate that this is because the viscosity of NOA63 was so high that the considered spinning speed range was too low. Moreover, the silver-nanowire-embedded electrodes in NOA63 showed the lowest thickness difference at a spin speed of 250 rpm. In fact, because of the high viscosity of NOA63, a low spin speed was insufficient to spread out and remove the prepolymer from the substrate. Thus, all the polymer dropped contributed to the formation of the film. A uniform dropping of NOA63 could result in a low thickness deviation. The thickness ratio of all the films appeared to be in the 40-60% range, with an average of approximately 50%, except for the NOA63 one, which was spin-coated at a very low speed. Thus, we conclude that, similar to SU8, NOAs have a specific thickness ratio independent of the spinning speed and prepolymer solution viscosity, with values similar to those of SU8. Finally, we prepared PTB7:PC\({}_{71}\)BM solar cells with silver-nanowire-embedded flexible transparent electrodes made with NOA and compared their performance at different positions with different thicknesses to examine the effect of the thickness difference on the performance. Figure 6 shows the J-V characteristics of organic solar cells located at the center and edge of silver nanowire flexible electrodes. Although their thickness was slightly different in different locations, the cells showed comparable characteristics. The open-circuit voltage and short-circuit current density of the solar cells located at the center were 0.73 V and 17.11 mA/cm\({}^{2}\), respectively, resulting in a power conversion efficiency of 6.12%, and those of the solar cells located at the edge were 0.74 V and 17.82 mA/cm\({}^{2}\), resulting in a power conversion efficiency of 6.80%. This indicates that the performance of the flexible electrodes is comparable and is independent of the location and thickness difference of the electrode film.