## 2 Experimental Details  
Figure 1 illustrates the fabrication process for UAPR-coated Ag nanowire TE. A 0.15 wt% Ag nanowire solution in isopropyl alcohol (IPA) was purchased from Nanopy-xis and used without post-treatment. The Ag nanowires had an average diameter and length of \(\sim\)35 nm and \(\sim\)15 \(\upmu\)m, respectively. The Ag nanowire solution was coated on a polyethylene terephthalate (PET, Kolon Inc.) substrate with a thickness of 125 \(\upmu\)m using doctor blading, as shown in Figure 1a. The blade height and speed were fixed at 150 \(\upmu\)m and 10 mm/s, respectively. To remove the solvent, the as-coated Ag nanowires were dried in ambient air at 80 \({}^{\circ}\)C for 10 min using a convection oven. UAPR resin containing \(\sim\)1.5 wt% 1-hydroxycyclohexylhenyl berlotene as the photoinitiator was provided by BASP, which was then coated onto the Ag nanowire samples using the same doctor blading system (Figure 1b). The blade height and the blading speed for this step were 160 \(\upmu\)m and 10 mm/s, respectively. The coated Ag nanowire TEs were then exposed to UV light with a light intensity of 30 mW/cm\({}^{2}\) at 365 nm for 60 s using a UV chamber (KGW-94 N, KAIS) as shown in Figure 1c,d. The resulting cured UAPR coating had a thickness of 3 \(\upmu\)m as measured using an Alpha-Step (KLA Tencor, D-500), which was the thinnest layer that could be achieved in this study. Below 3 \(\upmu\)m, the thickness of the coating was non-uniform through the sample, while the thickest layer possible using our fabrication system that did  
not lose its uniformity was \(\sim\)10 \(\upmu\)m. There was no major difference in the optical properties of the layer up to a thickness of \(\sim\)10 \(\upmu\)m, which showed an optical transmittance of \(\sim\)91.3% up to \(\sim\)10 \(\upmu\)m. The cured UAPR exhibited a pencil hardness of 2H; in a crosshatch adhesion test using scotch tape, no lifting was observed, confirming that the UAPR had suitable adhesion to the PET substrate.  
The sheet resistance of the Ag nanowire TEs was measured using a non-contact sheet resistance measurement system ([PERSON], EC-80) to prevent potential damage caused by the probes of the conventional contact-based measurement system. Before the coating process, the sheet resistance of the Ag nanowire TEs was measured using both the non-contact system and a typical four-point probe method (FPP-2400). For the same samples, the sheet resistance values were similar when measured using the non-contact and four-point probe methods. After the coating had been applied, the resistance measured using the non-contact system did not change significantly when compared to the resistance of the bare electrode. These results confirmed that there was no significant difference in the sheet resistance measured by the contact and non-contact systems. The sheet resistance before and after UAPR coating was \(\sim\)50.6 ohm/sq and \(\sim\)51.3 ohm/sq, respectively. Optical transmittance was characterized using an optical transmittance measurement system (BYK, haze-gard i). Bright-field optical images of the UAPR-coated Ag nanowire TEs were taken using an optical microscope (Nikon, Eclipse LV150N). The detailed microstructure of the samples was analyzed using a scanning electron microscope (FE-SEM, XL30 ESEM-FEG, Phillips). Bending tests were performed by using a manual bending tester (Woorim Tech.) under the condition of a 3 mm bending radius and 100 bending cycles. For bending tests, the samples were cut into 5 cm \(\times\) 5 cm sizes, and both ends of the samples were clamped to the clip of the upper and lower plates of the bending tester. By folding and unfolding the upper and lower plates, the bending strain was applied to the samples. During every 20 cycles of bending, the sheet resistance and optical transmittance were measured in the bent region of the samples.