Fabrication of Hydrogen Boride Thin Film by Ion Exchange in MgB2

T Hirabayashi; S Yasuhara; S Shoji; A Yamaguchi; H Abe; S Ueda; H Zhu; T Kondo; M Miyauchi

doi:10.3390/molecules26206212

Fabrication of Hydrogen Boride Thin Film by Ion Exchange in MgB₂

Molecules. 2021 Oct 14;26(20):6212. doi: 10.3390/molecules26206212.

Authors

T Hirabayashi^{1

2}, S Yasuhara¹, S Shoji^{1

3}, A Yamaguchi¹, H Abe⁴, S Ueda^{5

6

7}, H Zhu², T Kondo^{8

9}, M Miyauchi¹

Affiliations

¹ Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo 152-8552, Japan.
² Department of Mechanical Engineering, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
³ Department of Materials Science & Engineering, Cornell University, Ithaca, NY 14853, USA.
⁴ Center for Green Research on Energy and Environmental Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan.
⁵ Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Hyogo 679-5148, Japan.
⁶ Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, Tsukuba 305-0047, Japan.
⁷ Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan.
⁸ Department of Materials Science and Tsukuba Research Center for Energy Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan.
⁹ Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503, Japan.

Abstract

In this study, hydrogen boride films are fabricated by ion-exchange treatment on magnesium diboride (MgB₂) films under ambient temperature and pressure. We prepared oriented MgB₂ films on strontium titanate (SrTiO₃) substrates using pulsed laser deposition (PLD). Subsequently, these films were treated with ion exchangers in acetonitrile solution. TOF-SIMS analysis evidenced that hydrogen species were introduced into the MgB₂ films by using two types of ion exchangers: proton exchange resin and formic acid. According to the HAXPES analysis, negatively charged boron species were preserved in the films after the ion-exchange treatment. In addition, the FT-IR analysis suggested that B-H bonds were formed in the MgB₂ films following the ion-exchange treatment. The ion-exchange treatment using formic acid was more efficient compared to the resin treatment; with respect to the amount of hydrogen species introduced into the MgB₂ films. These ion-exchanged films exhibited photoinduced hydrogen release as observed in a powder sample. Based on the present study, we expect to be able to control the morphology and hydrogen content of hydrogen boride thin films by optimising the ion-exchange treatment process, which will be useful for further studies and device applications.

Keywords: hydrogen boride; hydrogen release; ion-exchange; pulsed laser deposition; thin film.

Abstract

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