UCLA researchers in the Department of Materials Science and Engineering have developed a simple solution-based method for fabricating highly conductive transparent silver nanowire (AgNW) films with excellent adhesive capabilities and noteworthy electrical, mechanical, and optical performance.
Indium-Tin-Oxide (ITO) is the most widely used transparent conductive film on the market because it provides high transparency and low sheet resistance. Although ITO has been used for several decades, the increase demand and low availability of natural indium sources has created an urgent need to develop other transparent conductive electrode technologies. Some potential candidate materials proposed to replace ITO include carbon nanotubes, graphene or thin metal films. However, these technologies all come at the cost of compromising between optical transparency and electrical conductivity. Recently, scientists have turned to silver nanowire (AgNW) networks to achieve a viable transparent conductor with comparable performance to ITO.
Researchers at UCLA have developed a highly conductive and transparent AgNW mesh composite film. Pretreating the AgNW before deposition with a TiO2 sol-gel solution improves connections between nanowires, thus enhancing the electrical performance. Subsequently, treating the AgNW film with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) enhances the AgNW adhesion to the substrate and improves the film’s mechanical properties. The overall film demonstrates a transparency of 83% at 550 nm and a sheet resistance of 15 ohm/sq, which is comparable to ITO. The untreated AgNW are commercially available and the film is readily fabricated through solution-processed methods such as blade-coating, in comparison to ITO which uses more tedious vacuum deposition techniques. This film can also be applied to large area applications through roll-to-roll processing. The film was used in an organic photovoltaic device and showed similar performance to a device using ITO. Thus, this invention demonstrates a simple and efficacious solution-based method to achieve highly conductive AgNW films with good transparency and excellent adhesion on the substrate.
Researchers have fabricated the material and are collecting and analyzing additional data.
|United States Of America||Issued Patent||9,460,999||10/04/2016||2012-112|
nanowire, AgNW, Indium-Tin-Oxide, ITO, transparent conductive film, carbon nanotubes, graphene