Novel Insights into Inkjet Printed Silver Nanowires Flexible Transparent Conductive Films.

Yuehui Wang,Hui Xie,Kaiwen Lin,Jingze Li,Xiaoli Wu,Ke Wang,Xiaobing Zhang

doi:10.3390/ijms22147719

Abstract

Silver nanowire (AgNWs) inks for inkjet printing were prepared and the effects of the solvent system, wetting agent, AgNWs suspension on the viscosity, surface tension, contact angle between ink droplet and poly(ethylene) terephthalate (PET) surface, and pH value of AgNWs ink were discussed. Further, AgNWs flexible transparent conductive films were fabricated by using inkjet printing process on the PET substrate, and the effects of the number printing layer, heat treatment temperature, drop frequency, and number of nozzle on the microstructures and photoelectric properties of AgNWs films were investigated in detail. The experimental results demonstrated that the 14-layer AgNWs printed film heated at 60 °C and 70 °C had an average sheet resistance of 13 Ω∙sq−1 and 23 Ω∙sq−1 and average transparency of 81.9% and 83.1%, respectively, and displayed good photoelectric performance when the inkjet printing parameters were set to the voltage of 20 V, number of nozzles of 16, drop frequency of 7000 Hz, droplet spacing of 15 μm, PET substrate temperatures of 40 °C and nozzles of 35 °C during printing, and heat treatment at 60 °C for 20 min. The accumulation and overflow of AgNWs at the edges of the linear pattern were observed, which resulted in a decrease in printing accuracy. We successfully printed the heart-shaped pattern and then demonstrated that it could work well. This showed that the well-defined pattern with good photoelectric properties can be obtained by using an inkjet printing process with silver nanowires ink as inkjet material.

Highlights

In recent years, silver nanowires (AgNWs) flexible transparent conductive films (FTCFs) with excellent comprehensive performance have attracted considerable attention and research because AgNWs networks can provide desirable electrical conductivity, excellent transmittance, and great flexibility [1,2,3,4,5]
The solvent system has a significant effect on the nozzle clogging during the inkjet printing process, stability of ink, and the uniform film forming during the drying [9,35,36]
We believe that our research works play an important role in promoting inkjet printing processes in preparing flexible AgNWs transparent electrodes or circuits with well-defined patterns

Summary

Introduction

Silver nanowires (AgNWs) flexible transparent conductive films (FTCFs) with excellent comprehensive performance have attracted considerable attention and research because AgNWs networks can provide desirable electrical conductivity, excellent transmittance, and great flexibility [1,2,3,4,5]. In the past few years, many great efforts have been made to develop the preparation technology and promote the performance of AgNWsFTCFs, including spray coating [10], gravure printing [11], screen printing [8,12], inkjet printing [9,13,14], and eletrohydrodynamic jet printing [15] These methods have the advantages of simple operation, high efficiency, time efficiency, and low cost, they still present many challenges, such as poor uniformity and repeatability and controllability of samples, and the subsequent laser etching process to achieve graphics, which greatly restricts the promotion and application of the AgNWs-FTCFs in flexible devices [10,11,12,13,14,15]. The preparation of inkjet inks is often a challenging issue for researchers

Methods

Results

Conclusion