Transparent conductive film has conductivity at the same time under high light transmission, which is an indispensable important industrial basic material in the field of optoelectronics. With the development of optoelectronic devices in the direction of large size, thinness, flexibility, and low cost, the demand for high-performance flexible and stretchable transparent conductive films has grown rapidly.
Currently, the widely used transparent conductive materials are mainly ITO film or glass, but their high resistance and brittle structure limit their use in flexible optoelectronic devices. Newly developed conductive polymers, carbon materials and metal nanomaterials Flexible transparent conductive film generally has the problem of mutual conductivity and transmittance. The resistance below 85% transmittance is usually more than tens of ohms per square.
Metal grid transparent conductive film
The metal grid transparent conductive film etched based on the copper foil yellow light process has the advantages of high conductivity and high transmittance and has been widely concerned by the industry, but the process is complicated, and the pollution caused by the acid etching process and copper ions and its high cost cannot be ignored. The printed electronics research team led by the researcher of the Institute of Nanoscience and Technology of the Chinese Academy of Sciences in Suzhou has independently developed an embedded silver grid transparent conductive film for printing additive manufacturing. The transmittance and conductivity can be independently adjusted, and the resistance is lower than 85%. At 10Ω / □, it has been successfully applied to touch screens and realized industrialization. It has won the 2014 Chinese Patent Gold Award.
In order to further promote the application of printed metal grid transparent conductive film in wider fields such as transparent magnetic shielding, electric heating film, transparent 5G antenna, etc., how to further improve the conductive property of conductive film under high transmittance has become an important task for the team. Research objectives.
Recently, Su Wenming's research team at the Suzhou Institute of Nanotechnology, Chinese Academy of Sciences optimized the structure parameters of the stamping mold based on the hybrid printing additive manufacturing technology to achieve a groove structure of 2: 1 aspect ratio and 4μm line width, combined with scraping The seed layer of the thin-layer nano-silver ink is filled with dense copper in the groove by electro-deposited copper technology. Because the metal copper is completely restricted to grow in the groove only in one direction during the electrodeposition process, the expansion of the wire is avoided, and a copper grid with a high aspect ratio is obtained. Therefore, the metal grid is increased without affecting the light transmittance. Thickness, at the same time, the electroplated grid has high intrinsic copper conductivity. At 86% high light transmittance, the square resistance is as low as 0.03 Ω / □, and the FOM value exceeds 80,000. (FOM is the comprehensive quality factor of transparent conductive film. , Refers to the ratio of light transmission to square resistance, such as ITO's FOM <300).
Professor Cui Yan graduated from Southeast University with a master's degree, a master's degree, and a doctoral degree. In September 1989, he was funded by the Visiting Fellowship of the British Science and Engineering Research Council (SERC Visiting Fellowship) and went to the Microelectronics Research Centre of Cambridge University as a visiting fellow . In 1993, he was hired as a Senior Scientist at the Microstructure Center of Rutherford National Laboratory, UK. Principal Scientist of the Center's micro-nano technology since 1999, and head of the Microsystem Technology Centre at Rutherford National Laboratory, until September 2009 at Rutherford National Laboratory The Micro-Nano Technology Center (MNTC) is responsible for the engineering application (Group Leader) of micro-nano technology.
In October 2009, he joined the Suzhou Institute of Nanotechnology, Chinese Academy of Sciences (full-time), and established the first printed electronics research center in China. The center currently has more than 70 scientific research team members and a completed laboratory area of more than 2,000 square meters. Carried out research and development in various fields from printed electronic ink synthesis to process and equipment research, printed photovoltaics, printed thin film transistors, printed organic and quantum dot light emission, and printed flexible stretchable electronics.