Traditional touchscreen displays in computers, tablets and phones uses electrodes made from indium tin oxide (ITO). The shortfalls of this technology are energy usage and production costs.
Alan Dalton, a Professor of Experimental Physics at the University of Sussex, recently led a study that investigated producing detailed electrode structures by patterning intricate silver nanowire films. The team believes that their solution is suitable for high definition LCD displays as well as touchscreens, and will be used in the next generation of computer screens and television. Energy usage and production costs for this technology are lower when compared to current technology.
Dalton’s team has previously done research that show that silver nanowires exceeds the transmittances and conductivities of ITO films. This in itself makes the material very attractive for touch screens. As it is also possible to produce extremely small pixels, the nanomaterial is also compatible with more challenging applications including LCD and OLED displays.
Dalton explains that current technology uses pixels to form images. Each pixel of the displays is then split into three subpixels for the primary colors red, green and blue. The subpixels are typically less than a sixth of the width of a human hair in smartphones. The silver nanowires used in the new research is similar in length.
The lead author of the paper Dr Matthew Large, notes that the team used a mathematical technique to calculate the smallest subpixel size that can be produced without influencing the properties of the nanowire electrodes. This mathematics used was originally developed to describe how phase changes like freezing occur in very small spaces. From these calculations, the researchers know how to adjust the nanowires to meet the requirements of any given application.
The team hopes to apply these research results to commercial projects. To achieve this, they are collaborating with an industrial partner, M-SOLV based in Oxford. To this end, they have proven that incorporating silver nanowires into a multi-touch sensor reduces energy usage and production costs.
Dalton is of the opinion that silver nanowire and silver nanowire/graphene hybrids are the most viable substitutes for existing technologies. Although several alternative materials have been studied by other research teams, it was found that most other materials do not compete with ITO effectively, or they are too expensive to produce.
The paper titled, “Finite-size scaling in silver nanowire films: design considerations for practical devices”, is published in the journal Nanoscale.