Gensys 10 series

In this study, the AgNP solution samples without any rinsing were directly analyzed by an UV-Vis (Gensys 10 Series, Thermo Scientific, Waltham, MA, USA). The morphological properties of the Ag nanoparticles were studied using an H-7100 (Hitachi, Tokyo, Japan) TEM. XRD (Empyrean, Malvern Panalytical, Malvern, UK) was used to further characterize the nanoparticles. Measurements of the Ag conductive ink viscosities were carried out using a DV3T viscometer (Brookfield Engineering Laboratories, Middleboro, MA, USA). The surface tension of Ag conductive ink was assessed using Model 100SB (Sindatek Instruments, New Taipei, Taiwan). Finally, electrical resistivity of the patterns was measured using a Surfcorder ET3000 microfigure measuring instrument (Kosaka Laboratory, Tokyo, Japan) and a Keithley 2000-EM4P four-point probe analyzer (Tektronix, Beaverton, OR, USA).

In this study, the CuNP solution samples without any rinsing were directly analyzed by UV–vis (Gensys 10 Series, Thermo Scientific, Waltham, MA, USA). The morphological properties of the CuNPs were studied using an H-7100 TEM (Hitachi, Tokyo, Japan). Measurement of the Cu conductive ink viscosity was carried out using a DV3T viscometer (Brookfield Engineering Laboratories, Middleboro, MA, USA). XRD (Empyrean, Malvern Panalytical, Malvern, UK) was used to further characterize the CuNPs. The surface tension of Cu conductive ink was assessed using a Model 100SB device (Sindatek Instruments, New Taipei, Taiwan). Fourier-transform infrared (FTIR) spectroscopy (FT/IR-6000, Jasco International Co., Tokyo, Japan) was used to confirm the functional groups change of PET before and after surface modification, and atomic force microscopy (AFM; XE-100, Park Scientific Instruments, Sunnyvale, CA, USA) was used to measure the surface roughness. Finally, the electrical resistivity of the patterns was measured using a Surfcorder ET3000 microfigure measuring instrument (Kosaka Laboratory, Tokyo, Japan) and a Keithley 2000-EM4P four-point probe analyzer (Tektronix, Beaverton, OR, USA).