Nonlinear Photoluminescence Spectroscopy of Carbon Nanotubes with Localized Exciton States

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• 作者：Munechiyo Iwamura ; Naoto Akizuki ; Yuhei Miyauchi ; Shinichiro Mouri ; Jonah Shaver ; Zhenghong Gao ; Laurent Cognet ; Brahim Lounis ; Kazunari Matsuda
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：November 25, 2014
• 年：2014
• 卷：8
• 期：11
• 页码：11254-11260
• 全文大小：467K
• ISSN：1936-086X

文摘

We report distinctive nonlinear behavior of photoluminescence (PL) intensities from localized exciton states embedded in single-walled carbon nanotubes (SWNTs) at room temperature. We found that PL from the local states exhibits strong nonlinear behavior with increasing continuous-wave excitation power density, whereas free exciton PL shows only weak sublinear behavior. The strong nonlinear behavior was observed regardless of the origin of the local states and found to be nearly independent of the local state density. These results indicate that the strong PL nonlinearity arises from a universal mechanism to SWNTs with sparse local states. The significant nonlinear PL is attributed to rapid ground-state depletion of the local states caused by an efficient accumulation of photogenerated free excitons into the sparse local states through one-dimensional diffusional migration of excitons along the nanotube axis; this mechanism is verified by Monte Carlo simulations of exciton diffusion dynamics.

Keywords:

carbon nanotube; nonlinear; photoluminescence; exciton; localized; trapped