Open AccessConvection‐Flow‐Assisted Preparation of a Strong Electron Dopant, Benzyl Viologen, for Surface‐Charge Transfer Doping of Molybdenum Disulfide
Author(s) -
Matsuyama Keigo,
Fukui Akito,
Miura Kohei,
Ichimiya Hisashi,
Aoki Yuki,
Yamada Yuki,
Ashida Atsushi,
Yoshimura Takeshi,
Fujimura Norifumi,
Kiriya Daisuke
Publication year - 2019
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201900169
Subject(s) - dopant , molybdenum disulfide , doping , materials science , molecule , viologen , nanotechnology , transition metal , nanomaterials , chemical engineering , chemical physics , photochemistry , optoelectronics , chemistry , organic chemistry , composite material , catalysis , engineering
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 (BV 0 ); however, the problem remains of how to effectively prepare the BV 0 molecules. A reduction process with NaBH 4 in water has been proposed as a preparation method, but the NaBH 4 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 NaBH 4 to prepare the BV 0 dopant molecules. The prepared BV 0 molecules show a strong doping ability in terms of achieving a degenerate situation of a TMDC, MoS 2 . A key finding in this preparation method is that a convection flow in the vial effectively transports the produced BV 0 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.