Development of Metal Substitution and Nano compositing of Carbon in NiO Nanosheets for Dye Sensitized Solar Cells Applications

Abstract

Dye-sensitized solar cells (DSSCs) are an innovative type of solar technology newlineknown for their cost-effectiveness and flexibility compared to traditional silicon-based newlinesolar cells. Despite their potential, the widespread adoption of DSSCs has been newlinehindered by certain limitations. A major challenge is the reliance on platinum (Pt)-based newlinecounter electrodes (CEs), which are both expensive and lack long-term stability. newlineTo overcome these issues, this thesis focuses on developing cost-effective and durable newlinealternatives to Pt-based CEs. Specifically, it investigates two-dimensional hexagonal newlinemesoporous nickel oxide nanosheets (2D-HM NiO NSs) as promising replacements. newlineThe 2D-HM NiO NSs were synthesized via a simple hydrothermal method, and newlinethe CEs were fabricated using the doctor blade technique. The NiO-based DSSCs newlineexhibited excellent electrocatalytic performance towards iodide-based electrolytes, newlineowing to the high specific surface area and mesoporous structure of the NiO NSs. newlineThe resulting DSSCs achieved the power conversion efficiency (and#951;) of 4.06%, closely newlinematching the efficiency of conventional Pt-based CE (4.19%). To further improve the newlineelectrocatalytic activity and electrical properties of the NiO NSs, the study explored newlinetwo key modifications: (1) introducing metal ions (Ti, Co, and Li) into the NiO structure newlinethrough a one-step hydrothermal process, and (2) creating nanocomposites by newlinecombining NiO nanosheets with carbon allotropes, such as carbon nanofibers (CNFs) newlineand multi-walled carbon nanotubes (MWCNTs). The nanocomposites were prepared newlineusing a co-precipitation method, in which the hydrothermally synthesized NiO NSs newlinewere integrated with carbon materials. These modifications aimed to enhance both the newlineelectrocatalytic and electrical properties of the CEs. As with the pure NiO electrodes, newlineall modified CEs were fabricated using the doctor blade technique newline