Excitonic solar cells (ESCs) such as Dye Sensitized Solar Cells (DSCs) and Organic Solar Cells (OSCs) are promising candidates of third generation photovoltaics. Immense research has been carried out in these areas for the last two decades, focusing on improving the device performance and stability in order to make it economically viable. Nanostructured binary metal oxide semiconductors (n-MOS) form an inevitable part in ESCs. In this thesis, Molybdenum Oxide (MoO3) and Zinc Oxide (ZnO) is used as hole and electron transporting interfacial layers respectively. This doctoral research further identifies that the depth of trap states in the band gaps of these n-MOS which originates as a result of structural disorders, plays a dominant role in determining the efficiency and stability of OSCs. By engineering the buffer layers to have a reduced trap depth, the possibilities to combine high efficiency and operational stability in OSCs is demonstrated. The study is further extended to DSCs, in which an n-MOS, Tin Oxide (SnO2) serves as a charge separation and electron transport medium (photoelectrode). Optimization of the SnO2 photoelectrode with reduced trap states, significantly improved the photovoltaic performance and also exhibited record open circuit voltage.
|Qualification||Doctor of Philosophy|
|Award date||14 Aug 2013|
|Publication status||Published - 2013|