The Stoichiometry of TCNQ-Based Organic Charge-Transfer Cocrystals

Jiaoyang Gao,Huifei Zhai,Hui Jiang,Peng Hu

doi:10.3390/cryst10110993

Abstract

Organic charge-transfer cocrystals (CTCs) have attracted significant research attention due to their wide range of potential applications in organic optoelectronic devices, organic magnetic devices, organic energy devices, pharmaceutical industry, etc. The physical properties of organic charge transfer cocrystals can be tuned not only by changing the donor and acceptor molecules, but also by varying the stoichiometry between the donor and the acceptor. However, the importance of the stoichiometry on tuning the properties of CTCs has still been underestimated. In this review, single-crystal growth methods of organic CTCs with different stoichiometries are first introduced, and their physical properties, including the degree of charge transfer, electrical conductivity, and field-effect mobility, are then discussed. Finally, a perspective of this research direction is provided to give the readers a general understanding of the concept.

Highlights

Organic charge-transfer cocrystals (CTCs) is a new type of molecular crystal which is composed of organic donor and acceptor, in which electrons can transfer from the donor to the acceptor molecules [1,2,3,4,5,6,7,8]
Three gas-phase methods are used for the single-crystal growth of organic CTCs (Figure 5), temperatures of organic donors and acceptors are nearly equal, the starting materials can be mixed depending on the sublimation temperatures of the starting materials
The vapor pressure of the individual components determines the amount of donor/acceptor molecules sublimed to the single crystals zone, and further defines the stoichiometry of CTCs

Summary

Introduction

Organic charge-transfer cocrystals (CTCs) is a new type of molecular crystal which is composed of organic donor and acceptor, in which electrons can transfer from the donor to the acceptor molecules [1,2,3,4,5,6,7,8]. Three gas-phase methods are used for the single-crystal growth of organic CTCs (Figure 5), temperatures of organic donors and acceptors are nearly equal, the starting materials can be mixed depending on the sublimation temperatures of the starting materials. If the sublimation together and put into a two-zone furnace with an argon gas flow for the single-crystal growth The vapor pressure of the individual components determines the amount of donor/acceptor molecules sublimed to the single crystals zone, and further defines the stoichiometry of CTCs. the stoichiometry of the final crystals is random.

Schematic for the ‘‘D’’

Method

The Degree of Charge Transfer

Infrared

The Electrical Conductivity and Field-Effect Mobility

Conclusions