Photoluminescence and electrical conductivity measurement of liquid crystal doped with ZnO nanoparticles

ABSTRACT

We report the effect of dispersion of zinc oxide (ZnO) nanoparticles (NPs) on the conductivity, birefringence and fluorescence properties of commercially available room temperature nematic liquid crystal (LC) with the variation of dopant concentration. Significant changes have been observed in transition enthalpy, DC conductivity, photoluminescence and birefringence values of the LC material by the addition of ZnO NPs. While the inclusion of NPs enhances the electrical conductivity of the composite system, it results in a reduction in the birefringence value, which can be attributed to a decrease in the order parameter of the system due to the perturbed geometry of the LC. This also results in the increase in threshold voltage value, which has been speculated as due to the piezoelectric nature of the ZnO NPs. The analysis of the fluorescence spectrum indicates that ZnO NPs enhance the intensity in the LC phase along with a small blue shift.

Graphical Abstract

KEYWORDS:

• Liquid crystal
• LC nanocomposite
• birefringence
• electrical conductivity
• photoluminescence

Acknowledgments

We (SKL and NP) gratefully acknowledge the financial support by the DAE-BRNS, under a BRNS project having grant number 2013/34/24/BRNS/2676 dated 17 December 2013. SKL is also thankful to VGST for financial assistance via the project having sanction number VGST/SMYSR(2014-15)/GRD-454/2015-16 dated 11 November 2015. We also sincerely thank Kenji Sakamoto, Nissan chemicals, Tokyo Japan for donating polyimide solution SE6414.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We (SKL and NP) gratefully acknowledge the financial support by the DAE-BRNS, under a BRNS project having grant number 2013/34/24/BRNS/2676 dated 17 December 2013. SKL is also thankful to VGST for financial assistance via the project having sanction number VGST/SMYSR(2014-15)/GRD-454/2015-16 dated 11 November 2015.