UC Riverside

The synthesis and characterization of metal-oxide photoelectrodes used for various devices that produce a renewable energy source is studied and discussed in this dissertation. Due to the various applications of nanoscale metal-oxide materials there is a variety of characterization and synthesis methods. This work controls the morphology, layer stack, and composition of metal-oxide by adjusting synthesis parameters and methods. Chapter 2 discusses the synthesis of a ZnO-CuO structure which incorporates a

ZnO nanorod core within a CuO thin film shell to use as a photocathode. A desirable diameter and length of the ZnO core is achieved by adjusting the synthesis parameters such as the ratio of oxygen to nitrogen gas, temperature, and the flow rate of gas.

Continuing onto Chapter 3, the fabrication process of dye-sensitized solar cells which utilize the synthesized ZnO-CuO core-shell as a photoelectrode is discussed. The effects on the stability and performance of the CuO shell on the ZnO core implemented in the

dye-sensitized solar cells is then investigated. The CuO shell on the ZnO core successfully prevents the dissolution of Zn atoms during the dye absorption reaction on the surface of the photoelectrode. In Chapter 4, the effects of a Cu interlayer between Cu2O

photocathode and a transparent conductive film is studied for the use in the photoelectrochemical water splitting reaction. The physical deposition process and chemical reaction are used to study the formation of a desirable structure within the thin

film stack. This method successfully fabricates a Cu2O layer that intentionally removes the Cu interlayer or prevents the formation of a Cu interlayer with varying thickness. The intercalated Cu layer between Cu2O and transparent conductive film prevents charge

separation and accelerates its recombination during the photoelectrochemical reaction. Chapter 5 discusses the introduction of a doping method into the CuO crystal lattice structure. CuO is synthesized onto a transparent conductive film through

electrodeposition. Zn doped-CuO is synthesized by adding a Zn dopant precursor into the electrodeposition solution. The electrodeposition process is optimized by controlling the applied potential, dopant concentration, temperature, and reaction time.