Meter-scale single-wall carbon nanotube (SWCNT) thin films with an excellent optoelectrical performance has been developed for the first time by researchers at Institute of Metal Research of Chinese Academy of Sciences. The results were published in Advanced Materials.

The production of high-quality SWCNT thin films by an efficient and scalable method has become a key issue for their practical application in electronics. However, two major obstacles remain for the research and development of macro-electronics based on SWCNT thin films.

First, the size of fabricated SWCNT films is usually limited to the square centimeter scale, and the batch processing used is not scalable. Second, the optoelectrical performance of SWCNT films remains unsatisfactory due to the introduction of impurities and structural defects during the fabrication processes.

In this study, researchers proposed a continuous synthesis, deposition, and transfer technique.

By a floating catalyst chemical vapor deposition technique, SWCNTs were continuously synthesized and deposited on a repeatedly used moving membrane filter forming SWCNT thin films. Then, the as-deposited film was transferred onto a flexible poly(ethylene terephthalate) substrate with the aid of a roll-to-roll transfer system, therefore the length of the SWCNT film is unlimited.

As there are no impurities and defects introduced in the production processes, these SWCNT films have an excellent optoelectrical performance including a low sheet resistance of 65 Ω/□ with a transmittance of 90% at a wavelength of 550 nm.

In addition, researchers fabricated large-area, flexible, and transparent all-CNT thin-film transistors (TFTs) and various integrated circuits (ICs) to demonstrate the potential use of these SWCNT thin films in large-area, flexible, and transparent electronics. All-CNT TFTs and ICs including 101-stage ring oscillators showed excellent performance and uniformity.

"The meter-scale high-quality SWCNT films and the devices fabricated from them will pave the way for future development of large-scale, flexible, and transparent electronics based on SWCNT thin films,” one of the paper's co-author WANG Bingwei said.

SWCNTs have been considered one of the most promising candidates for flexible and transparent electronic devices due to their extraordinary mechanical, electrical, and optical properties.