Lecture: One-Dimensional Pd(III) Mott-Insulators: Phase Transition, Charge Fluctuation, and Devices by Prof. Masahiro Yamashita

One-Dimensional Pd(III) Mott-Insulators: Phase Transition, Charge Fluctuation, and Devices

Speaker:

Prof. Masahiro Yamashita

Time:

10:00-11:00 Oct 22, 2021

Venue:

Online: Tencent Conference, ID: 336 856 800

Abstract:

Quasi-one-dimensional halogen-bridged complexes of Ni, Pd and Pt have been attracting much attention because they show very interesting chemical and physical properties such as intense inter-valence charge transfer bands, progressive overtones of resonance Raman spectra, luminescence spectra with large Stokes-shifts, mid-gap absorptions attributable to soliton and polaron. Recently, we have found the largest third-order optical nonlinearity in [NiIII(chxn)2Br]Br2 with the strong electron-correlation (~10-4 esu). Generally speaking, the Pd complexes form the Pd(II)-Pd(IV) mixed-valence states, where the bridging halogens are displaced from the midpoints between neighboring two Pd atoms along the chain, due to the electron-phonon interaction, while the Ni complexes forms the Ni(III) Mott-Hubbard states, where the bridging halogens are located at midpoints between the neighboring two Ni atoms along the chain, due to the strong electron-correlation. Recently, Pd(en)2Br(C5-Y)2 with sulfonic acid counter-ions of the long alkyl chain shows the phase transition between the Pd(II)-Pd(IV) mixed-valence state and Pd(III) Mott-Hubbard state around 205K. The Pd compounds with sulfonic acid of 9 and 12 alkyl chains take the Pd(III) states even at room temperature for the first time. Pd(cptn)2Br3 show the charge fluctuation and charge separation between Pd(III) state and Pd(II)-Pd(IV) mixed-valence state. Finally, I will talk about their devices composed of the Ni-Pd hetero-junctions. 

Brief Introduction of the Speaker:

Professor Masahiro Yamashita now works at Tohoku University in Japan. He received his Ph.D. from Kyushu University in Japan in 1982, and then engaged in research work in many well-known scientific research institutions, such as Japan Molecular Institute, Kyushu University, Nagoya University, Tokyo Metropolitan University, London University, etc. Professor Masahiro has been engaged in the research of molecular-based magnetic materials, functional complexes and nano-materials and made important contributions. Up to now more than 300 papers have been published in Nature, Nature Commun, JACS, Angew, and Chem. He has won Innovation Award of Japan Chemical Society in 2005, Inoue Award in 2012 and Coordination Chemistry Award in Japan in 2014.