High-performance single-walled carbon nanotube transparent conducting film fabricated by using low feeding rate of ethanol solution

We report floating catalyst chemical vapor deposition synthesis of single-walled carbon nanotubes (SWCNTs) for high performance transparent conducting films (TCFs) using low feeding rate of precursor solution. Herein, ethanol acts as carbon source, ferrocene and thiophene as catalyst precursor and growth promoter, respectively. By adopting a low feeding rate of 4 μl/min, the fabricated TCFs present one of the lowest sheet resistances of ca. 78 ohm/sq. at 90% transmittance. Optical characterizations demonstrate that the mean diameter of high quality SWCNTs is up to 2 nm. Additionally, electron microcopy observations provide the evidences that the mean length of SWCNT bundles is as long as 28.4 μm while the mean bundle diameter is only 5.3 nm. Moreover, very few CNT loops can be found in the film. Remarkably, the fraction of individual SWCNTs climbs up to 24.6%. All those morphology data account for the superior optoelectronic performance of our SWCNT TCFs.

本研究报道了采用低前驱体溶液进料速率，通过浮动催化剂化学气相沉积（floating catalyst chemical vapor deposition）法合成用于高性能透明导电薄膜（transparent conducting films, TCFs）的单壁碳纳米管（single-walled carbon nanotubes, SWCNTs）的工艺。本实验中，以乙醇作为碳源，以二茂铁（ferrocene）与噻吩（thiophene）分别作为催化剂前驱体与生长促进剂。通过采用4微升/分钟的低进料速率，所制备的透明导电薄膜在90%透光率下的方阻低至约78欧姆每平方，属于当前同类材料的优异水平之一。光学表征结果显示，所制备的高质量单壁碳纳米管的平均直径可达2纳米。此外，电子显微镜观测结果证实，单壁碳纳米管束的平均长度可达28.4微米，而管束的平均直径仅为5.3纳米。尤为关键的是，该薄膜中几乎未观测到碳纳米管环结构。值得注意的是，单根单壁碳纳米管的占比高达24.6%。上述所有形貌表征数据，均为本研究制备的单壁碳纳米管透明导电薄膜具备优异光电性能提供了合理的解释与有力支撑。