Scialog: Solar Energy Conversion - 2013
Towards a Tunable Platform for Exploring Band Alignment and Mediating Efficient Charge Transfer: Combining Quantum Confinement wit
Sarbajit Banerjee and David Watson, both chemistry researchers at State University of New York at Buffalo, are working to improve the way we use sunlight to split water into its component atoms of hydrogen and oxygen. “Developing methods for solar energy conversion is arguably the greatest challenge facing scientists, today,” they said. “Carbon-neutral energy is needed to mitigate the catastrophic effects of CO2 emissions on the environment.” The team is working with a $200,000 Scialog grant from RCSA. Banerjee and Watson are focusing their research on the fantastically small realm of the nanoscale – a nanometer, for example, is one-billionth the size of a meter. Working at such a tiny scale intrigues physicists and chemists because matter sometimes behaves much differently at the nanoscale than it does on the much larger scale of everyday life. The pair and their students will be working with nanowires composed of a form of the compound vanadium pentoxide, which is known for its catalytic abilities. In chemistry, a catalyst is a substance that accelerates or retards a chemical reaction without itself being consumed. To complicate matters, Banerjee and Watson will chemically equip their nanowires with quantum dots (incredibly tiny bits of material) composed of compounds already proven to be good at converting sunlight into electricity. This conversion occurs when particles of light, called photons, slam into an atom and knock an electron (normally in “orbit” around the atom’s center or nucleus) out of the grip of the nucleus. If these free electrons are made to flow in one direction, an electrical current results. Banerjee and Watson plan to test a number of promising compounds, taken from sections I through VI of the Periodic Table of Elements, in an effort to fine-tune the quantum dots’ interaction with molecular scaffolds based on the vanadium-pentoxide nanowires. Also, they hope to design the quantum dots to absorb a maximum number of photons, freeing a maximum number of electrons to decouple hydrogen atoms from the two oxygen atoms in a molecule of water. The vanadium-pentoxide nanowires are expected to facilitate the flow of electrons towards quantum dots to enable subsequent catalytic reactions. By experimenting with various quantum dot compounds on nanowires, they hope to produce a “tunable,” or reconfigurable, platform to further explore the most efficient ways to produce hydrogen, which one day may be needed in massive quantities to fuel our machines.