Uniform TitleDye sensitized solar cells using ZnO nanotips and Ga doped ZnO films
NameChen, Hanhong (author), Lu, Yicheng (chair), Panayatatos, Paul (internal member), Sheng, Kuang (internal member), Jiang, Wei (internal member), Du Pasquier, Aurelien (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectElectrical and Computer Engineering,
Solar cells--Design and construction,
Dye-sensitized solar cells,
DescriptionDye sensitized solar cell (DSSC) is a promising and low-cost photovoltaic device. In the DSSC, a monolayer of dye is anchored on the surface of a semiconductor oxide. Photoexcitation takes place inside the dye, and photogenerated charges are then separated at the dye/oxide interface. Nanostructured oxide films are particularly attractive for DSSCs as they provide large surface area for dye anchoring. The crystalline quality of oxide films has significant impact on the charge transport. It is important to reduce the charge traps in the oxide to speed up the charge transport. In the DSSC, the transparent conducting oxide serves as an optical window, which determines the amount of light entering the device, and as the electrode, which extracts photocurrent. In the cell design, the selection of semiconductor oxide and corresponding transparent electrode is critical to achieve efficient light harvesting, charge separation and extraction.
In this dissertation, a novel photoelectrode, consisting of well-aligned ZnO nanotips and a Ga-doped ZnO (GZO) TCO film, is developed for DSSC applications. The n-type semiconductor ZnO nanotips provide large surface area for dye anchoring in conjunction with direct conduction pathways for charge transport, while the GZO film acts as the transparent electrode. ZnO nanotips and GZO films are grown by metalorganic chemical vapor deposition (MOCVD). GZO films (~400 nm) with sheet resistance of ~ 25 W/sq and transmittance over ~ 85% are achieved. ZnO nanotips have single crystalline quality and show free exciton emissions at room temperature. Photoelectrochemical cells are fabricated using liquid redox electrolyte and semi-solid gel electrolyte, respectively. UV light harvesting, which is directly generated by ZnO photoelectrode, is observed. The DSSC using liquid electrolyte exhibits a quantum efficiency at ~530nm of 65% and power conversion efficiency of 0.77%. By replacing the liquid electrolyte with gel electrolyte in the DSSC with the same structure, the open circuit voltage is increased from 610 mV to 726 mV and the overall power efficiency is increased to 0.89%. The aging testing shows that the DSSC using gel electrolyte has better stability than its liquid electrolyte counterpart.
NoteIncludes bibliographical references (p. 118-122).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.