Meter-scale single-wall carbon nanotube (SWCNT) thin films with an excellent optoelectrical performance has been developed for the first time by Chinese researchers from Institute of Metal Research, Chinese academy of sciences.

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. 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. Therefore, the production of high-quality SWCNT thin films by an efficient and scalable process remains a big challenge.

Recently, researchers from Institute of Metal Research, Chinese academy of Sciences (IMR, CAS), proposed a continuous synthesis, deposition, and transfer technique for the fabrication of high-quality SWCNT thin films of meter-scale dimension with excellent optoelectrical performance. Large-area, flexible, and transparent all-CNT thin-film transistors (TFTs) and various integrated circuits (ICs) were also fabricated to demonstrate the potential use of these SWCNT thin films in large-area, flexible, and transparent electronics. Those findings have been published on 28 June, 2018 in Advanced Materials.

SWCNTs are continuously synthesized by a floating catalyst chemical vapor deposition technique, and then deposited on a moving membrane filter forming SWCNT thin films. The length of the SWCNT film is unlimited, because the as-deposited film is transferred onto a flexible poly(ethylene terephthalate) substrate with the aid of a roll-to-roll transfer system, and the membrane filter can be repeatedly used for the SWCNT film collection.

More importantly, as there are no impurities and defects introduced in the production processes, the 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. Using these SWCNT thin films, all-CNT TFTs and ICs including 101-stage ring oscillators have been constructed that show excellent performance and uniformity.

“The present method enables us first to achieve continuous production including the growth, deposition, transfer and re-deposition of SWCNTs.” the paper’s co-first authors, WANG Bing-Wei and JIANG Song said. “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.”

Contact
HUANG Chengyu
Institute of Metal Research
E-mail:cyhuang@imr.ac.cn