pps proceeding - Abstract Preview
pps proceeding
Symposium: S19 - Special Symposium: Microtechnology and smart materials
Oral Presentation
 
 

Silver Miniwires Grids Made by co-Electrospinning for Transparent Conductive Applications

Claracq Jerome (1)*, Bashir Mubasher (1), de Graaf Michael (1), Joo Jake (2)

(1) Dow Benelux - Zeeland - Netherlands, (2) Dow Electronic Materials - Massachusetts - USA

Transparent conductive applications such as touch enabled displays require transparent electrodes to have minimal sheet resistance (Rs) and high optical clarity. Traditionally, indium tin oxide (ITO) is used as the standard transparent conductive material (TCM) to make the electrode of many optoelectronic devices. However ITO is struggling to deliver the combination of a very high clarity and very low Rs necessary for large surface panels. Among the candidates to replace ITO, silver miniwires meshes are closer to industrial scale production. However traditional printing techniques to make metal meshes currently suffer from a low production rate and large feature size. In the present communication, we are demonstrating the making of high performance transparent electrodes from a conductive grid of silver miniwires with co-electrospinning (co-ES) process. We spun, directly on a flexible PET film, bi-component fibers with low viscosity silver nanoparticle ink in the fiber core and a polymeric outer sheath. We achieved fiber alignment by means of a high speed rotary collector drum. A mesh was then obtained by turning 90° the PET sheet between two co-ES passes. In a post-processing step, the silver fibers were exposed to high photonic energy. The heat generated was sufficient to sinter the silver nanoparticles. We were successful in producing conductive PET films with low Rs=19 Ohm/sq and high clarity (T=89.4%, H=3.1%). The wires were hardly visible because of the small size (3 µm) and low moiré effect due to the co-ES overcoat. It is possible to reduce the haze further with smaller fiber size or using glass substrate. In that case such conductive layer would have a very low haze of 1.2% and a transparency higher than 97%. Therefore this fabrication method looked as a competitive approach to incumbent and coming TCM technologies. Keywords: microprocessing, rheology, nanoparticle suspension, electrospinning, metal nanofibers, transparent electrodes, touch screen