Presentation Information
[7p-N406-5]Nontrivial temperature dependence of shift current observed in DAST derivatives
〇Andrew Harold Gibbons1,2, Gurvan Bosser3, Masao Nakamura2,3,6, Naoki Ogawa2,3, Yoshinori Tokura3,4,5, Satoshi Okamoto1,2 (1.Sumitomo Chemical, 2.RIKEN BZP, 3.RIKEN CEMS, 4.Univ. of Tokyo, 5.Tokyo College, 6.Tohoku University)
Keywords:
shift current,bulk photovoltaic effect,organic nonlinear optical materials
Since the shift current is a current with almost no energy dissipation, it is expected to significantly improve the photoelectric conversion efficiency. Shift currents have been reported mainly in non-centrosymmetric inorganic materials, particularly ferroelectrics, topological insulators etc., but there have been few reports of shift currents in organic materials. In this report, we present our study of shift currents in organic nonlinear optical (NLO) materials, which are non-centrosymmetric. Among organic NLOs, DAST (4-N,N dimethylamino -4′-N′-methyl -stilbazolium tosylate) is one of the most well-known organic nonlinear optical material. There have been several reports on the photocurrent of DAST single crystals, but so far none of them have observed a shift current, which is the photocurrent at zero bias. We have succeeded for the first time in observing a shift current in single crystals of DAST and its derivatives. We also found that this shift current is a nontrivial phenomenon that increases exponentially with temperature. In this presentation, we will also report the results of our investigation into the mechanism behind this phenomenon.