**2. Materials and Methods**

#### *2.1. Materials*

The nano-Ag composite paste was made by ultrasonically mixing the 30 nm Ag NPs and the 30 nm SiOx NPs with a specific weight ratio such as 0.1 wt%, accompanied by organic vehicles that included surfactants, binders, and thinners [16]. Figure 1a shows that the surfactant, binders, and thinners are dissolved by acetone in a beaker as a mixture. As seen from Figure 1b, in order to disperse the SiOx NPs and the Ag NPs uniformly in the mixture, the mixture was stirred at 2000 rpm for 10 min using a planetary centrifugal mixer (THINKY ARE310).
