[21a-231C-1~11] 12.2 Characterization and Materials Physics

▲ [21a-231C-3] Signal Dynamics from Single Molecule Junction of Cyclo[8]pyrrole-SiW₁₂O₄₀ Complex

〇(DC)Nunik Nurhayati¹, Zhijin Chen¹, Yosuke Tani¹, Ken-Ichi Yamashita¹, Hidemitsu Uno², Takuji Ogawa¹ (1.Osaka Univ., 2.Ehime Univ.)

Keywords:polyoxometalate, real-time current, hidden Markov model

Recently we have reported a molecular neuromorphic network device consisting of single-walled carbon nanotubes (SWNT) complexed with polyoxometalate (POM).^[1] In the previous work we postulated multi-molecule network is indispensable for spiking dynamics, which can be used for rudimentary computing such as reservoir computing. Here we studied single molecule electronic dynamics of POM derivatives reported by Okujima and co-workers (Cyclo[8]pyrrole-SiW₁₂O₄₀, POM-de-ring),^[2] in which cyclo[8]pyrrole work as an anchoring group for single molecule junction.^[3]
Current versus time traces of a single POM-de-Ring junction at a constant bias voltage were measured using mechanically controllable break junction technique. Time traces with large spike currents were observed with the high/low ratio ~10³. We also acquired time traces at several different bias voltages and temperatures. Hidden Markov model analyses with multi-level of conductance states show that the signals are not random and show clear dynamics.

References
[1] H. Tanaka, M. Akai-Kasaya, A. TermehYousefi, L. Hong, L. Fu, H. Tamukoh, D. Tanaka, T. Asai, T. Ogawa, Nat. Comm., in press, 2018.
[2] T. Okujima, H. Matsumoto, S. Mori, T. Nakae, M. Takase, H. Uno, Tetrahedron Lett., 2016, 57, 3160-3162.
[3] T. Tamaki, T. Ohto, R. Yamada, H. Tada, T. Ogawa, ChemSelect, 2017, 2(25), 7484-7488.