Greenly synthesized titanium dioxide nanoparticles for modulation of dielectric and electro-optical properties of nematic liquid crystal

Green synthesis of nanoparticles (NPs) is a straightforward, non-toxic, and economical approach that serves as a substitute for the harmful effects associated with conventional NP synthesis methods. The present study demonstrates the green synthesis of Titanium Dioxide nanoparticles (TiO2 NPs) from Carica papaya (C. papaya) leaves and then their dispersion within the nematic liquid crystal (4-pentyl-4′-biphenylcarbonitrile, 5CB) having different concentrations (0.05, 0.1, 0.3, and 0.5 wt%). Greenly synthesized TiO2 NPs were characterized by XRD, UV–visible spectroscopy, FTIR, and HRTEM. XRD results confirmed the formation of anatase TiO2 NPs with an average crystallite size of 2.09 nm. The existence of lattice fringes in HRTEM is evident in the crystalline nature of the NPs having an average particle size of 5.5 nm. Moreover, synthesized TiO2 NPs were further dispersed in 5CB NLC to modulate its various dielectric and electro-optical properties for various LC-based applications. The prepared composites were characterized for textural, dielectric, electro-optical, and optical properties. The investigation evident uniform distribution of NPs in NLC, increased birefringence and dielectric strength reduced threshold voltage and driving voltage, and enhanced photoluminescence intensity up to 0.3 wt%, while aggregation of NPs occurred at high concentration (0.5 wt%) leading to a decline in the optical and dielectric characteristics of 5CB. In summary, our research provides evidence that the optimal concentration of greenly synthesized TiO2 NPs in TiO2 NPs-5CB composites can enhance their dielectric and electro-optical characteristics, thereby rendering them appropriate for a range of photonics and display applications that prioritize sustainability, environmental safety, and superior performance. © 2024 Elsevier B.V.