(Invited) Wafer-Scale Probing of Natural and Synthetic Chirality in Carbon Nanotubes

Harnessing chirality can advance diverse technologies, encompassing displays, quantum light sources, secured communication, and biosensing. We have investigated chirality-induced processes in carbon nanotube (CNT) ensembles, based on both natural and synthetic chirality, on macroscopic scales. Firstly, through enantiomer purification [1] combined with nanotube alignment [2], we demonstrated second harmonic generation in an aligned film of (6,5)+ single enantiomer-enriched CNTs. Enantiomer purification using mixed-surfactant gel chromatography and CNT alignment through controlled vacuum filtration (CVF) resulted in a resonance-enhanced second-order nonlinear optical susceptibility χ (2) of ~2 nm/V at the E 11 exciton transition. Secondly, we engineered artificial chiral assemblies from achiral mixtures of CNTs to create chiral structures, achieving a record high deep-ultraviolet ellipticity of 40 mdeg/nm [3]. Our orbital shaking-assisted CVF methodology enabled the fabrication of a macroscopic assembly of synthetic optical isomers, so-called “tornado” films, obtaining both types of handedness within a single film by fine-tuning a shaking-filtration recipe. References: [1] X. Wei, T. Tanaka, Y. Yomogida, N. Sato, R. Saito, H. Kataura, Experimental determination of excitonic band structures of single-walled carbon nanotubes using circular dichroism spectra, Nature Communications 7 (2016) 12899. https://doi.org/10.1038/ncomms12899. [2] X. He, W. Gao, L. Xie, B. Li, Q. Zhang, S. Lei, J.M. Robinson, E.H. Hároz, S.K. Doorn, W. Wang, R. Vajtai, P.M. Ajayan, W.W. Adams, R.H. Hauge, J. Kono, Wafer-scale monodomain films of spontaneously aligned single-walled carbon nanotubes, Nature Nanotechnology 11 (2016) 633–638. https://doi.org/10.1038/nnano.2016.44. [3] J. Doumani, M. Lou, O. Dewey, N. Hong, J. Fan, A. Baydin, K. Zahn, Y. Yomogida, K. Yanagi, M. Pasquali, R. Saito, J. Kono, W. Gao, Engineering chirality at wafer scale with ordered carbon nanotube architectures, Nature Communications 14 (2023) 7380. https://doi.org/10.1038/s41467-023-43199-x.