Title: Structure, Property, Processing Correlations of Laser-Induced Graphene

Program: Materials Science and Engineering PhD

Committee Chair: David Estrada

Committee: David Estrada, Brian Jaques, Tony Valayil-Varghese, Jessica Koehne

Abstract: Laser-induced graphene (LIG) is an emerging graphitic material with high surface area, tunable electrical properties, and a scalable, direct-write fabrication pathway that is well suited for flexible electronics and sensing applications. Conventional LIG synthesis relies predominantly on carbon dioxide (10.6 µm) lasers, which are limited by diffraction-constrained resolution, high system cost, and bulk photothermal heating that restricts integration with high-density and lightweight electronic architectures.

This dissertation establishes a novel synthesis framework for laser-induced graphene using a previously unexplored visible-wavelength (450 nm) laser, enabling high-resolution patterning, reduced thermal damage, and compatibility with low-power, benchtop manufacturing platforms. By systematically investigating laser fluence, scan speed, and environmental conditions, this work elucidates the structure–property–processing correlations governing LIG formation, morphology, defect density, and electrical performance.

Terrestrial synthesis studies demonstrate the formation of nanocrystalline, defect-rich graphene with feature sizes approaching 15 µm, suitable for flexible and additively manufactured electronic devices. Building on this foundation, the synthesis process is extended to reduced-gravity environments, where the suppression of buoyancy-driven convection fundamentally alters thermal transport and gas evolution during graphitization. Microgravity experiments reveal significant differences in porosity, crystallinity, and defect distribution relative to terrestrial LIG, establishing gravity as a first-order processing variable in laser-induced graphene synthesis.

The developed material platform is applied to the fabrication of flexible chemiresistive gas sensors capable of detecting plant-emitted volatile organic compounds, demonstrating the suitability of visible-wavelength LIG for in-situ environmental monitoring. The fundamental study of laser–matter interactions in graphene synthesis establishes a scalable, low power manufacturing pathway for functional electronics in both terrestrial and space based environments.