Fabrication and Characterization of Semiconductor Thin Films (2012)

Undergraduates: Anna Curtis, Stephen Miller

Faculty Advisor: Andrew Moran
Department: Chemistry

---

In the 1980s Michael Grätzel developed what we now refer to as dye-sensitized solar cells. However, this form of renewable energy is dependent on sunlight. The Energy Frontier Research Center (EFRC) at UNC is working towards development of a renewable energy resource similar to the Grätzel cell but with the ability to store energy in the form of various fuels (methanol, H2, etc.) which can be used in the absence of sunlight. Semiconductors with appropriate band gaps and a valence band which is close to the lowest unoccupied molecular orbital (LUMO) of the dye are essential in improving the efficiency and thus development of these cells. Titanium dioxide, a well-known semiconductor, has demonstrated a favorable band gap which is essential for development of these cells. Studies of the properties of titanium dioxide as well as other semiconductors are important for the development of these devices. The semiconductors are best utilized in the form of thin films which enhance optical studies. The titanium dioxide films consist of nanoparticles which ranged in size from 10nm-20nm. Studies were performed on these titanium dioxide thin films using Absorption Spectroscopy, Fluorescence Spectroscopy, Spontaneous Raman Microscopy and Scanning Electron Microscopy (SEM) to better understand their chemical properties.