Transparent conductive films for touch screen applications using silver nanowire electrodes have been widely researched over the past few years. Silver nanowires are considered especially promising as transparent conductive film electrodes because silver has the highest conductivity of any metal. Films comprised of silver nanowires can also be mechanically flexible and possess attractive optical properties such as low haze and high transparency.
For silver nanowire films produced in a roll-to-roll coating process, one of the major drawbacks can be the variation in sheet resistance (hereafter referred to as resistance) measured in the machine direction (downweb or MD) versus the transverse direction (crossweb or TD). Typically, the resistance in the transverse direction, RTD, is higher than the resistance in the machine direction, RMD. Values of RTD/RMD of 1.5-2.0 are not uncommon. This resistance anisotropy can create inefficiencies in the touch screen module fabrication process.
This article describes experimental work aimed at developing a fundamental understanding of the causes of resistance anisotropy in transparent conductive films containing silver nanowires. The effect of key process parameters on sheet resistance anisotropy is also discussed.
Read the entire article, Sheet Resistance Anisotropy in Transparent Conductive Films Containing Silver Nanowires, in the 2017 Quarter 1 issue of Converting Quarterly.