Computational Study of Molecular Dyes, Surface Chemistry of Atomic Layer Deposition (ALD), and Precursors for MBE
This group's work with organic dyes for dye sensitized solar cells (DSSCs) is furthered by computational work to understand the dye’s structure, orbital density, and energy levels. The experimental data yields binding constants and electron transfer rates of dyes to zinc oxide nanocrystals. The group has been able to find that the electronic coupling (tied to orbital overlap) affects the electron transfer which computational studies were done to visualize the important orbitals. Understanding this information can assist in creating better dyes for DSSCs by improving binding and electron transfer efficiency.
Currently, computations have been started on terthiophene dye molecules with different binding groups. The effect of deprotonating the dye on the structure and orbital density is still being investigated and could be of importance since the dye is deprotonated when attached to the zinc oxide nanocrystals. In addition, time-dependant studies are being done to compare computationally and experimentally the absorption of the dyes. This project will continue terthiophene optimization calculations with the possibility of investigating rhenium-based compounds. How these dyes bind and transfer electrons to zinc oxide is important since it could increase efficiency of cells if that is the rate-determining step.
A second project studying the surface chemistry in atomic layer deposition (ALD) is ongoing. Studies focus on determining intermediates in the ALD process to better understand a partial mechanism of depositing the ALD films that is consistent with the data.
Future work for the ALD project will focus on investigating organocopper and organotin complexes and reactive intermediates. In addition, work focusing on the interactions between organoaluminum complexes and polystyrene will be investigated. The interaction with ozone as well as water with these compounds is useful for understanding the mechanism of forming the ALD films. These films have applications for transparent conducting oxides used in industrial applications.
A new project focused on molecular beam epitaxy (MBE) will focus on the precursor effects on deposition on surfaces. In order to create effective films, it is important to understand how the precursors interact with the surfaces they are deposited on, as well as their structures, which can contribute to high quality crystal growth in specific MBE experiments. With these experiments, the resesarchers can computationally screen precursors for MBE experiments to improve depositions.
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