Photoswitchable Polar Azobenzene-Based Liquid Crystals for Electro-Optic and Optical Data Storage Applications

In contemporary world, photoswitchable materials have gathered growing interest for application in solar energy harvesting, data storage, artificial muscles, smart sensors, and many more. Here, we present a new series of polar rod-like molecules incorporating the photoswitchable azobenzene (-N═N-) moiety, demonstrating both nematic and orthogonal smectic phases. Electro-optic measurements conducted in the nematic phase of compound 2c (dipole moment μ = 8.8 D) revealed a spontaneous polarization (P _s ) of approximately 1.38 μC/cm², while compound 2b in the SmA phase showed P _s around 1.74 μC/cm². Crystal structure analysis of compound 2c sheds light on the inherent molecular arrangement within the crystal lattice. Photoisomerization studies revealed robust and consistent photochromic behavior across all studied compounds, exhibiting high photo conversion efficiencies ranging from 83% to 93% under UV illumination, along with uniform back relaxation times of approximately 20 h. Optical storage devices fabricated from these materials demonstrated exceptional contrast between dark and bright states, underscoring their significant potential for next-generation data storage technologies.