Convection-Flow-Assisted Preparation of a Strong Electron Dopant,Benzyl Viologen,for Surface-Charge Transfer Doping of Molybdenum Disulfide |
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Authors: | Keigo Matsuyama Akito Fukui Kohei Miura Hisashi Ichimiya Yuki Aoki Yuki Yamada Prof Atsushi Ashida Prof Takeshi Yoshimura Prof Norifumi Fujimura Prof Daisuke Kiriya |
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Institution: | Department of Physics and Electronics, Osaka Prefecture University, 1–1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka, 599-8531 Japan |
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Abstract: | Transition metal dichalcogenides (TMDCs) have received attention as atomically thin post-silicon semiconducting materials. Tuning the carrier concentrations of the TMDCs is important, but their thin structure requires a non-destructive modulation method. Recently, a surface-charge transfer doping method was developed based on contacting molecules on TMDCs, and the method succeeded in achieving a large modulation of the electronic structures. The successful dopant is a neutral benzyl viologen (BV0); however, the problem remains of how to effectively prepare the BV0 molecules. A reduction process with NaBH4 in water has been proposed as a preparation method, but the NaBH4 simultaneously reacts vigorously with the water. Here, a simple method is developed, in which the reaction vial is placed on a hotplate and a fragment of air-stable metal is used instead of NaBH4 to prepare the BV0 dopant molecules. The prepared BV0 molecules show a strong doping ability in terms of achieving a degenerate situation of a TMDC, MoS2. A key finding in this preparation method is that a convection flow in the vial effectively transports the produced BV0 to a collection solvent. This method is simple and safe and facilitates the tuning of the optoelectronic properties of nanomaterials by the easily-handled dopant molecules. |
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Keywords: | transition metal dichalcogenides benzyl viologen redox reactions molecular doping convection flow |
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