University Presentation Showcase: Undergraduate Poster Gallery
MUSIC Industry (Recording Arts track)
Judith L. Jenkins
It is an inescapable truth that energy is needed to maintain the stability of life, but the mechanisms by which we acquire energy are finite. Combustion of fossil fuels, such as coal and oil, generate environmentally harmful by-products when burned for energy, and because demand for energy continues to grow, fossil fuels will no longer be sustainable as primary sources of energy. Solar energy is a very abundant form of energy, making solar energy a promising option for meeting future energy needs. However, solar energy is not currently absorbed nor converted to useable energy with 100% efficiency. Additionally solar energy cannot be practically stored for extended periods of time. New materials are needed to effectively convert, store, and use the energy in sunlight. Towards that end, this work focusses on the synthesis and analysis of lead-doped zinc sulfide nanocrystals (PbxZn1-xS NCs) to generate hydrogen gas using (and therefore storing) solar energy. When sunlight is absorbed by the NCs, the energy in sunlight generates high energy electrons in the NCs. When the NCs come in contact with hydrogen ions in water (H+), two excited electrons from NCs form a chemical bond between two H+ to yield hydrogen gas, H2. In this way, energy in the form of sunlight is converted into chemical energy practically packaged as a storable fuel. While ZnS NCs do not absorb much sunlight, introducing Pb dopant ions into the ZnS crystal lattice alters the optical properties of the NCs such that more sunlight is absorbed by the resulting doped crystals. However, controlled doping of nanocrystals is synthetically difficult. We hypothesize that changing the shape and size of the ZnS NCs may enable Pb doping which will enhance the NCs’ absorbance of sunlight. The primary challenges for this research are becoming familiar with the techniques, learning to interpret the data, and then using this data to refine our hypothesis. Initial experiments will focus on controlling the shape of the host ZnS NCs to be either rod-shaped, dot-shaped, or quasi-cubic. Then doping experiments will be conducted as a function of NC shape. If realized these nanostructures will influence the design of future synthesis of nanocrystals to be used for the generation of solar fuel.