Process optimization of simple preparation of AgNPs by polyol method and performance study of a strain sensor

Abstract

In this experiment, silver nanoparticles (AgNPs) were prepared by the polyol method, which is simple and low-cost. The AgNPs were characterized by SEM, UV–Vis, and XRD. It was determined that the prepared AgNPs had good morphology and the average particle size was about 53.01 nm. At the same time, the optimum conditions for preparation were determined: The molar ratio of polyvinylpyrrolidone K30 (PVP K-30) to AgNO3 was 6:1, the reaction time was 40 min, and the reaction temperature was 160 °C. Then the sintering process parameters were discussed. It was determined that when the content of AgNPs was 2.5%, the temperature of high-temperature sintering should reach 250 °C and above, the time should reach 30 min and above, and the lowest resistivity reaches 0.7 × 10−5 Ω·m under high-temperature sintering. In chemical sintering, Cl− replaces the N and O atoms of PVP K-30, induces spontaneous aggregation of Ag, and completes room temperature sintering. It is found that the sintering time needs to reach 30 min or more, and the resistivity is 3.325 × 10−5 Ω·m. Finally, the conductive region is printed by the material deposition system and the strain sensor is prepared by two sintering methods. The experimental test proves that the sensor prepared by high-temperature sintering has good cycle response and stability. The sensor prepared by chemical sintering has a good cycle response, but the repeatability is poor, which is not conducive to long-term high-strength use. The sensor can be applied to the field of flexible electronic products.