Synthesis of rod-shaped, spherical, and cubic zinc sulfide nanocrystals for energy conversion applications

Major

Chemistry

Department

Chemistry

Degree

Undergraduate

Mentor

Judith L. Jenkins

Mentor Department

Chemistry

Abstract

It is an inescapable truth that energy is needed to maintain the stability of life. Combustion of fossil fuels generates environmentally harmful by-products, 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, but is not currently absorbed nor converted to useable energy with 100% efficiency. New materials are needed to effectively convert, store, and use the energy in sunlight. This work focusses on the synthesis 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. 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. We hypothesize that changing the shape and size of the ZnS NCs may enable Pb doping which will enhance the NCs’ absorbance of sunlight. If realized these nanostructures will influence the design of future synthesis of nanocrystals to be used for the generation of solar fuel.

Presentation format

Poster

Poster Number

041

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Synthesis of rod-shaped, spherical, and cubic zinc sulfide nanocrystals for energy conversion applications

It is an inescapable truth that energy is needed to maintain the stability of life. Combustion of fossil fuels generates environmentally harmful by-products, 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, but is not currently absorbed nor converted to useable energy with 100% efficiency. New materials are needed to effectively convert, store, and use the energy in sunlight. This work focusses on the synthesis 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. 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. We hypothesize that changing the shape and size of the ZnS NCs may enable Pb doping which will enhance the NCs’ absorbance of sunlight. If realized these nanostructures will influence the design of future synthesis of nanocrystals to be used for the generation of solar fuel.