Tetracyanoquinodimethane and Its Derivatives as Promising Sustainable Materials for Clean Energy Storage and Conversion Technologies: A Review

7,7′,8,8′-tetracyanoquinodimethane (TCNQ) is one of the most widely studied redox-active molecules and effective π-acceptors, possessing excellent electrical properties. TCNQ derivatives are considered exciting materials due to their multitude of uses. TCNQ-based electrode and dopant materials offer enormous potential in revolutionary energy storage and conversion devices because of their safety, long-term stability, environmental friendliness, charge mobility, and low electrode potential. This review presents the most important advances in applications of TCNQ and its derivatives as promising sustainable organic materials for the optimization of electrical properties in energy storage and conversion devices compared to inorganic materials. This paper shows that materials based on TCNQ can be used as promising candidates for designing efficient and stable photovoltaics, sustainable batteries, and triboelectric nanogenerators, which are very important to the development of energy harvesting. The results presented in this review are sufficiently convincing for us to conclude that applying the TCNQ doping strategy to improve the performance of the discussed devices is very promising. The presented data could serve as inspiration for the development and subsequent design of new, effective, high-performance micro- and nano-systems based on TCNQ for energy storage and conversion.