Doctoral Dissertations

Orcid ID

http://orcid.org/0000-0001-7114-5424

Date of Award

12-2019

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Energy Science and Engineering

Major Professor

Ilia Ivanov

Committee Members

Phil Rack, Wim Bras, Bin Hu, Bobby Sumpter, Natalie Stingelin

Abstract

Novel functional materials are enabling transformational breakthroughs in energy, electronics, manufacturing and medicine. Development of new materials is being fueled by advances in high-performance computing, robotics, and high-throughput methods for materials synthesis and processing. To close the feedback loop between materials design, synthesis and functionality, novel materials must be rapidly screened for stability and functionality under a broad range of ambient environmental conditions. We developed an automated system for simultaneous probing of electrical, optical, gravimetric, and viscoelastic properties of materials under controlled environments, enabling characterization of material response to temperature, pressure, humidity, light intensity, and ambient gas/vapor composition. Control of environmental conditions, experimental procedures, and data acquisition were performed using custom integrated software with on-the-fly data processing and analytics. Real-time material response was used as feedback for iterative optimization of experiment settings, allowing automated initiation and termination of experimental procedures and reduced need for human researcher input. The system was used to characterize environmental response and sensing performance of a broad range of materials including polymers, metal oxides, organic small molecules, biomolecules, perovskites, nanotubes and two-dimensional materials. We found that material response to environment was generally mediated by charge transfer with adsorbate molecules, mechano-structural changes caused by diffusion of adsorbates into adsorbent films, production of mobile ions due to salt dissociation and formation of surface water layers, and photoexcitation of adsorbents by UV radiation. Material response often exhibited mixed-kinetics consisting of rapid gravimetric response during sorption of adsorbates on active surface sites, and slow electrical response resulting from diffusion of adsorbates into the bulk films. Here, we describe details of the multifunctional characterization system, show examples of functional materials characterized by the system, and describe potential future improvements to the system. Future opportunities for development include (i) integration of combinatorial synthesis methods to close the feedback loop between synthesis and characterization, (ii) integration of computational modeling for real-time feedback between experiment and simulation, (iii) database integration for creation of a materials expert system, and (iv) in situ diagnostics on X-ray and/or neutron beamlines for probing structure-function relationships under dynamic environments.

Comments

Portions of this document were previously published in ACS Nano, ACS Applied Materials and Interfaces, RSC Nanoscale, Nature Scientific Reports, SPIE Journal of Photonics for Energy, and Elsevier Sensors and Actuators B: Chemical.

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