Light-driven modulation of electrical conductance with photochromic switches: bridging photochemistry with optoelectronics.

Photochromic conducting molecules have emerged because of their unique capacity to modulate electrical conductivity upon exposure to light, toggling between high and low conductive states. This unique amalgamation has unlocked novel avenues for the application of these materials across diverse areas in optoelectronics and smart materials. The fundamental mechanism underpinning this phenomenon is based on the light-driven isomerization of conjugated π-systems which influences the extent of conjugation. The photoisomerization process discussed here involves photochromic switches such as azobenzenes, diarylethenes, spiropyrans, dimethyldihydropyrenes, and norbornadiene. The change in the degree of conjugation alters the charge transport in both single molecules and bulk states in solid samples or solutions. This article discusses a number of recent examples of photochromic conducting systems and the challenges and potentials of the field.