Synthesis and characterization of semiconducting copper oxide nanoparticles and their impact on the physical properties of a nematic liquid crystalline material 4-pentyl-4′-cyanobiphenyl

Green synthesis of nanoparticles is a biological, eco-friendly and less expensive method which is free from chemical contaminants. In this work, copper oxide nanoparticles (CuO NPs) have been synthesized via green synthesis method. This method proved to be efficient for preparing CuO NPs at room temperature without using any inert atmosphere. The CuO NPs have been characterized using X-Ray Diffraction, Ultraviolet-Visible Spec-troscopy and Fourier Transform Infrared Spectroscopy techniques which confirmed the proper synthesis of CuO NPs of the size 2-3 nm. Two different weight percents (0.2 and 0.5) of the synthesized CuO NPs have been dispersed in the nematogenic liquid crystalline material 4-pentyl-4 '-cyanobiphenyl (5CB). The physical prop-erties of pure 5CB and its nanocomposites were studied by differential scanning calorimetry, ultraviolet-visible spectroscopy and impedance spectroscopy. Thermodynamic and dielectric results show enhancement in the nematic to isotropic transition temperature of nanocomposites along with enhancement in conductivity as compared to its value for the pure 5CB. Through optical studies, the band gap has been estimated by the Tauc plots which suggest decrease in the optical band gaps of dispersed samples.

Automated summary

The green synthesis of copper oxide nanoparticles (CuO NPs) was successfully achieved using a biological, eco-friendly, and cost-effective method without requiring an inert atmosphere. The synthesized CuO NPs were characterized and confirmed to have a size of 2-3 nm through X-ray diffraction, ultraviolet-visible spectroscopy, and Fourier transform infrared spectroscopy techniques. Two different weight percentages (0.2 and 0.5) of the CuO NPs were dispersed in a liquid crystalline material (4-pentyl-4'-cyanobiphenyl, 5CB), and the physical properties of the pure 5CB and its nanocomposites were studied. The results showed enhancements in the nematic-isotropic transition temperature and conductivity, as well as a decrease in the optical band gaps of the dispersed samples.