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Unveiling Novel Energy Phenomena from Light Exposure on Layered Materials

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Research groups from the University of Tsukuba and the University of Rennes have discovered a novel phenomenon in which a nested structure of carbon nanotubes enveloped in boron nitride nanotubes facilitates a unique electron escape route when exposed to light. This finding introduces promising avenues for various applications, including the creation of high-speed optical devices, rapid control of electrons and other particles, and efficient heat dissipation from devices.

Tsukuba, Japan—In a collaborative work in the Dynacom framework (French Japanese Laboratory), recent studies have highlighted that materials composed of layered tubes, which are atomically thick and classified as low-dimensional materials, exhibit new properties. Although the static properties of these structures, such as electrical conduction, are well documented, their dynamic properties, including electron transfer between layers and atomic motion triggered by light exposure, have received less attention.

In this study, researchers constructed nested cylindrical structures by wrapping carbon nanotubes (CNTs) in boron nitride nanotubes. They then examined the motion of electrons and atoms induced by ultrashort light pulses on a one-dimensional (1D) material. Electron motion was monitored using broadband ultrafast optical spectroscopy, which captures instantaneous changes in molecular and electronic structures due to light irradiation with a precision of ten trillionths of a second (10−13 s). Atomic motion was observed through ultrafast time-resolved electron diffraction, which similarly achieved monitoring of structural dynamics with ten-trillionth-of-a-second accuracy.

The study revealed that when different types of low-dimensional materials are layered, a pathway or channel forms, allowing electrons to escape from specific subparts of the material. Additionally, it was found that electrons excited in the CNTs by light exposure could transfer into the BNNTs via these electronic channels, where their energy is rapidly converted into thermal energy, facilitating extremely fast thermal conversion.

This research has uncovered a new physical phenomenon at the interface between two dissimilar materials, offering not only ultrafast thermal energy transport but also potential applications in the development of ultrafast optical devices and the rapid manipulation of electrons and holes generated by light.

This work was supported by JSPS Kakenhi Grants-in-Aid [Nos. JP18H05208 (S.K.), JP22KK0225 (M.H.) and JP23H01101 (M.H.)] and the Japan Science Technology Agent (JST) FOREST Program [No. JPMJFR211V (M.H.)]. R.B. acknowledges Agence Nationale de la Recherche (ANR) for funding undergrant, ANR-21-CE30-0011-01 CRITICLAS.

Original Paper

Title of original paper:
Photoinduced dynamics during electronic transfer from narrow to wide bandgap layers in one-dimensional heterostructured materials
Nature Communications


Associate Professor HADA Masaki
Institute of Pure and Applied Sciences / Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba

Assistant Professor SUZUKI Hiroo
Faculty of Environmental, Life, Natural Science and Technology, Okayama University

Associate Professor OHMURA Satoshi
Faculty of Engineering, Hiroshima Institute of Technology

Associate Professor Roman Bertoni
Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)

Related Link

Institute of Pure and Applied Sciences

Tsukuba Research Center for Energy Materials Science (TREMS)

Celebrating the 151st 50th Anniversary of the University of Tsukuba
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