Date of Graduation

5-2017

Document Type

Thesis

Degree Name

Bachelor of Science in Mechanical Engineering

Degree Level

Undergraduate

Department

Mechanical Engineering

Advisor/Mentor

Wejinya, Uchechukwu C.

Committee Member

Wejinya, Uchechukwu C.

Second Committee Member

Tian, Ryan

Abstract

Graphene is known to be a key material for improving the performance of hydrogen sensors. High electrical conductivity, maximum possible surface area with respect to volume, and high carrier mobility are a few of the properties that make graphene ideal for hydrogen sensing applications. The problem with utilizing graphene is the difficulty in depositing uniform, thin layers onto substrate surfaces. This study examines a new method of optimizing graphene deposition by utilizing an airbrush to deposit both graphene oxide (GO) and reduced graphene oxide (rGO) onto glass substrates. The number of depositions were varied among samples to study the effect of layer thickness on the electrical and topographic properties of rGO. Linear sweep voltammetry tests show that increasing the amount of rGO deposited resulted in superior conductivity. Substrates coated with 5 spray-coats of rGO had a film conductivity of 0.35 S/m whereas substrates coated with 20 spray-coats displayed film conductivity of 7.67 S/m. An analysis of the topography of spray-coated rGO films revealed a rough and uneven surface texture resulting in hydrophobic wetting properties of rGO. When palladium nanoparticles were deposited onto rGO, samples demonstrated significant conductivity loss due to uneven palladium deposition and deformation of rGO. The unique electrical properties displayed by varying the amounts of deposited rGO establishes a method of hydrogen sensor fabrication with controllable rGO film conductivity.

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