(Invited) Formation of Organic Color Centers in Air-Suspended Carbon Nanotubes Using Vapor-Phase Reaction

Abstract

Organic color centers in single-walled carbon nanotubes have demonstrated exceptional ability to generate single photons at room temperature in the telecom range. Combining the color centers with pristine air-suspended nanotubes would be desirable for improved performance, but all current synthetic methods occur in solution which makes them incompatible. Here we demonstrate the formation of color centers in air-suspended nanotubes using a vapor-phase reaction [1]. Functionalization is directly verified by photoluminescence spectroscopy, with unambiguous statistics from more than a few thousand individual nanotubes. The color centers show strong diameter-dependent emission, which can be explained with a model for chemical reactivity considering strain along the tube curvature. We also estimate the defect density by comparing the experiments with simulations based on a one-dimensional exciton diffusion equation. Our results highlight the influence of the nanotube structure on vapor-phase reactivity and emission properties, providing guidelines for the development of high-performance near-infrared quantum light sources.This work is supported in part by MIC (SCOPE JP191503001 to Y.K.K.), JSPS (JP18H05329, JP20H00220 to S.M., JP20H02558 to Y.K.K., JP20K15112, JP22H01893 to D.K., JP20K15137 to K.O.), MEXT (Nanotechnology Platform JPMXP09F19UT0077), NSF (RAISE-TAQS PHY-1839165 to Y.H.W.), and JST (CREST JPMJCR20B5 to S.M.). D.K. acknowledges support from RIKEN Special Postdoctoral Researcher Program. K.O. is supported by JSPS Research Fellowship. We thank the Advanced Manufacturing Support Team at RIKEN for technical assistance.[1] D. Kozawa, X. Wu, A. Ishii, J. Fortner, K. Otsuka, R. Xiang, T. Inoue, S. Maruyama, Y. Wang, and Y. K. Kato, Nature Commun. 13, 2814 (2022).