Browsing by Author "Schneider, Harald"
Now showing 1 - 2 of 2
Results Per Page
- ItemFirst Terahertz-range Experiments on Pump – Probe Setup at Novosibirsk free Electron Laser(Amsterdam [u.a.] : Elsevier, 2016) Choporova, Yulia Yu.; Gerasimov, Vasily V.; Knyazev, Boris A.; Sergeev, Sergey M.; Shevchenko, Oleg A.; Zhukavin, Roman K.; Abrosimov, Nikolay V.; Kovalevsky, Konstantin A.; Ovchar, Vladimir K.; Hübers, Heinz-Wilhelm; Kulipanov, Gennady N.; Shastin, Valery N.; Schneider, Harald; Vinokurov, Nikolay A.A single-color pump-probe system has been commissioned at the Novosibirsk free electron laser. The laser emits a tunable monochromatic terahertz radiation. To prove the proper system operation, we investigated the time-resolved absorption of a sample of n-type germanium doped with antimony, which was previously investigated at the FELBE facility, in the temperature range from 5 to 40 K. The measured relaxation time amounted to about 1.7 ns, which agreed with the results obtained at the FELBE. The results of pump-probe measurements of non-equilibrium dynamics of hot electrons in the germanium crystal at cryogenic temperatures are presented for wavelengths of 105, 141 and 150 μm.
- ItemA Two-Dimensional Polyimide-Graphene Heterostructure with Ultra-fast Interlayer Charge Transfer(Weinheim : Wiley-VCH, 2021) Liu, Kejun; Li, Jiang; Qi, Haoyuan; Hambsch, Mike; Rawle, Jonathan; Vázquez, Adrián Romaní; Nia, Ali Shaygan; Pashkin, Alexej; Schneider, Harald; Polozij, Mirosllav; Heine, Thomas; Helm, Manfred; Mannsfeld, Stefan C.B.; Kaiser, Ute; Dong, Renhao; Feng, XinliangTwo-dimensional polymers (2DPs) are a class of atomically/molecularly thin crystalline organic 2D materials. They are intriguing candidates for the development of unprecedented organic–inorganic 2D van der Waals heterostructures (vdWHs) with exotic physicochemical properties. In this work, we demonstrate the on-water surface synthesis of large-area (cm2), monolayer 2D polyimide (2DPI) with 3.1-nm lattice. Such 2DPI comprises metal-free porphyrin and perylene units linked by imide bonds. We further achieve a scalable synthesis of 2DPI-graphene (2DPI-G) vdWHs via a face-to-face co-assembly of graphene and 2DPI on the water surface. Remarkably, femtosecond transient absorption spectroscopy reveals an ultra-fast interlayer charge transfer (ca. 60 fs) in the resultant 2DPI-G vdWH upon protonation by acid, which is equivalent to that of the fastest reports among inorganic 2D vdWHs. Such large interlayer electronic coupling is ascribed to the interlayer cation–π interaction between 2DP and graphene. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH