Chapter 32
Fabrication of Charge-Transfer Complex
Nanocrystals Toward Electric
Field-Induced Resistive Switching
Tsunenobu Onodera and Hidetoshi Oikawa
Abstract Charge-transfer complex exhibits versatile characteristics such as optical
properties, conductivity, and magnetism. The physicochemical properties can be
controlled through molecular design combining various kinds of electron donors
and acceptors. In particular, the degree of charge-transfer γ and the composition
ratio of electron donor to acceptor are important factors to determine physicochemical properties. On the other hand, nanocrystallized charge-transfer complex
would lead to unique properties, being different from both isolated molecule and
bulk crystal. However, the reprecipitation method for common organic nanocrystals
cannot be employed due to low solubility of charge-transfer complex in common
organic solvents. Therefore, novel nanocrystallization method for charge-transfer
complex should be developed. In this chapter, nanocrystallization involving doping
process of charge-transfer complex, copper 7,7,8,8-tetracyanoquinodimethane (CuTCNQ), will be introduced in detail towards nanoelectronics application. Cu-TCNQ
is typical Mott insulator and indicates a unique resistive switching behavior. It is
expected that Cu-TCNQ nanocrystals with an excess amount of Cu, namely doped
Cu-TCNQ nanocrystals, would show unique resistive switching behavior because of
the degree of charge-transfer γ different from bulk crystal.
Keywords Charge-transfer complexes · Nanocrystals · Doping
32.1 Introduction
Charge-transfer complex is one of the interesting research subjects because of versatile characteristics such as optical properties, conductivity, and magnetism [1]. Especially, electric and magnetic properties have been studied intensively because it is
possible to control physicochemical properties through molecular design combining
various kinds of electron donor and acceptor. The degree of charge-transfer γ and
T. Onodera (B) · H. Oikawa
Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University,
Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
e-mail: tsunenobu.onodera.a4@tohoku.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
H. Miyasaka et al. (eds.), Photosynergetic Responses in Molecules
and Molecular Aggregates, https://doi.org/10.1007/978-981-15-5451-3_32
551
Fabrication of Charge-Transfer Complex
Nanocrystals Toward Electric
Field-Induced Resistive Switching
Tsunenobu Onodera and Hidetoshi Oikawa
Abstract Charge-transfer complex exhibits versatile characteristics such as optical
properties, conductivity, and magnetism. The physicochemical properties can be
controlled through molecular design combining various kinds of electron donors
and acceptors. In particular, the degree of charge-transfer γ and the composition
ratio of electron donor to acceptor are important factors to determine physicochemical properties. On the other hand, nanocrystallized charge-transfer complex
would lead to unique properties, being different from both isolated molecule and
bulk crystal. However, the reprecipitation method for common organic nanocrystals
cannot be employed due to low solubility of charge-transfer complex in common
organic solvents. Therefore, novel nanocrystallization method for charge-transfer
complex should be developed. In this chapter, nanocrystallization involving doping
process of charge-transfer complex, copper 7,7,8,8-tetracyanoquinodimethane (CuTCNQ), will be introduced in detail towards nanoelectronics application. Cu-TCNQ
is typical Mott insulator and indicates a unique resistive switching behavior. It is
expected that Cu-TCNQ nanocrystals with an excess amount of Cu, namely doped
Cu-TCNQ nanocrystals, would show unique resistive switching behavior because of
the degree of charge-transfer γ different from bulk crystal.
Keywords Charge-transfer complexes · Nanocrystals · Doping
32.1 Introduction
Charge-transfer complex is one of the interesting research subjects because of versatile characteristics such as optical properties, conductivity, and magnetism [1]. Especially, electric and magnetic properties have been studied intensively because it is
possible to control physicochemical properties through molecular design combining
various kinds of electron donor and acceptor. The degree of charge-transfer γ and
T. Onodera (B) · H. Oikawa
Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University,
Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
e-mail: tsunenobu.onodera.a4@tohoku.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
H. Miyasaka et al. (eds.), Photosynergetic Responses in Molecules
and Molecular Aggregates, https://doi.org/10.1007/978-981-15-5451-3_32
551