Modern History of Organic Conductors: An Overview

Toshio Naito

doi:10.3390/cryst11070838

Abstract

This short review article provides the reader with a summary of the history of organic conductors. To retain a neutral and objective point of view regarding the history, background, novelty, and details of each research subject within this field, a thousand references have been cited with full titles and arranged in chronological order. Among the research conducted over ~70 years, topics from the last two decades are discussed in more detail than the rest. Unlike other papers in this issue, this review will help readers to understand the origin of each topic within the field of organic conductors and how they have evolved. Due to the advancements achieved over these 70 years, the field is nearing new horizons. As history is often a reflection of the future, this review is expected to show the future directions of this research field.

Highlights

At the beginning of this Special Issue of “Organic Conductors”, we will briefly review the history of the organic-conductor research field (~70 years), during which tens of thousands of related papers have been published for readers to better understand the background and significance of the work collected in this issue
It is expected that such a manner of citation would provide a comprehensive connection between different studies, papers, and topics, i.e., how they have evolved by interacting with each other and different research fields
The first “organic conductor” was unstable in air and possessed an unknown structure, it impacted the scientific community so greatly that it was succeeded by a series of significant findings, including the first organic metallic conductor TTF-TCNQ (TTF = tetrathiafulvalene, TCNQ = tetracyanoquinodimethane) in 1973 [23–29], doped polyacetylene in 1977 [30], superconducting TMTSF (TMTSF = tetramethyltetraselenafulvalene) in the 1980s [31–66], and BEDT-TTF (BEDTTTF = bis(ethylenedithio)tetrathiafulvalene) salts throughout the 1980s and 1990s [67–163]

Summary

Introduction

At the beginning of this Special Issue of “Organic Conductors”, we will briefly review the history of the organic-conductor research field (~70 years), during which tens of thousands of related papers have been published for readers to better understand the background and significance of the work collected in this issue. Unlike the conventional manner of citing scientific literature, the references in this review were collected in a broad context and are listed in chronological order, rather than classifying them into particular topics This was carried out to provide objective descriptions of the evolution and background of the various research topics in this field and the contributions of individual groups. The first “organic conductor” was unstable in air and possessed an unknown structure, it impacted the scientific community so greatly that it was succeeded by a series of significant findings, including the first organic metallic conductor TTF-TCNQ (TTF = tetrathiafulvalene, TCNQ = tetracyanoquinodimethane) in 1973 [23–29], doped polyacetylene in 1977 [30] (awarded the Nobel Prize in Chemistry in 2000), superconducting TMTSF (TMTSF = tetramethyltetraselenafulvalene) in the 1980s [31–66], and BEDT-TTF (BEDTTTF = bis(ethylenedithio)tetrathiafulvalene) salts throughout the 1980s and 1990s [67–163]. This was followed by the advent of doped-fullerene (fulleride) superconductors in 1991, which demonstrated transition temperatures (TCs) of ~18–30 K [164–177]

Renaissance of Organic Superconductors

The Return of 1D Systems

Mott Insulators

Light Control