Ultrasound-assisted facile and green preparation of Ag nanoparticle conductive ink for printing electronics

Abstract

The development of low-cost, high-efficiency, and environment-friendly methods for the preparation of Ag nanoparticle (NP) conductive inks is key to promoting the application of such inks for printing flexible electronic components. This article presents an effective method for preparing a AgNP ink by reducing silver compounds in a polyol solution with ultrasonication. When the silver solution was ultrasonicated at 640 W, 21-nm AgNPs were readily produced within 5 min, and the particles grew considerably to 53 nm as the reaction was continued for 15 min. Thereafter, the NP size increased marginally with further increase in reaction time. When the reaction was conducted for a fixed duration of 15 min and the ultrasonic power was increased from 480 to 760 W, the AgNP size decreased from 63 to 48 nm. During ultrasonication, the bubble eruption in the solution generates large temperature and pressure gradients, inducing the rapid reduction of the Ag(I) to Ag(0). Printing experiments revealed that the synthesized AgNP ink has good inkjet printability. During the sintering of the printed film, the bridge connections between large particles increased and the interparticle voids decreased gradually, resulting in a decrease in film resistivity. A relatively low resistivity of 40×10−5 Ωcm was obtained when the flexible AgNP pattern was heated at 250 °C for 80 min. The facile synthesis process and the favorable conductive properties of the obtained ink render this preparation method promising for the low-cost production of flexible electronics.