Fabrication of Metal Oxide Based Charge Transport Layer for Energy Conversion Devices

Abstract

Energy conversion devices such as perovskite solar cells, dye-sensitized solar cells, and electrochemical energy storage systems have gained significant attention due to their potential to provide efficient, low-cost, and sustainable alternatives to conventional energy technologies. A critical factor influencing the performance of these devices is the charge transport layer, which governs charge extraction, transport, and recombination processes at the interfaces. In this study, nickel oxide (NiO) and zinc oxide (ZnO) were synthesized and investigated as hole transport and electron transport materials, respectively, along with their LC sheet–based composite counterparts, for application in energy conversion and storage devices. NiO and ZnO nanoparticles were successfully synthesized using a simple and cost-effective coprecipitation method, while LC sheet–based composites were developed using corn fiber as a sustainable carbon source to enhance electrical conductivity and interfacial contact. The structural, electrochemical, and vibrational properties of the prepared materials were systematically characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Raman spectroscopy. CV analysis revealed that pristine NiO and ZnO exhibited pseudocapacitive behavior due to reversible redox reactions, whereas LC sheet–based composites showed predominantly capacitive behavior with improved rate capability, reversibility, and charge–discharge performance. The enhanced electrochemical performance of the composites is attributed to the conductive carbon network provided by the LC sheet, which facilitates rapid electron transport and efficient ion diffusion.