Functional nanostructured coatings via flow-limited field- injection electrostatic spraying: syntheses and applications

Vesto, Riley Elis

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https://hdl.handle.net/2142/124613 Copy

Description

Title

Functional nanostructured coatings via flow-limited field- injection electrostatic spraying: syntheses and applications

Author(s)

Vesto, Riley Elis

Issue Date

2023-11-27

Director of Research (if dissertation) or Advisor (if thesis)

• Kim, Kyekyoon
• Choi, Hyungsoo

Doctoral Committee Chair(s)

Kim, Kyekyoon

Committee Member(s)

• Dallesasse, John
• Bayram, Can

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• nanotechnology
• electronic devices
• solution-phase processing
• topological insulator
• perovskite solar cells

Abstract

Thin films and nanostructured coatings are the building blocks to many forms of micro- and nanotechnologies used in electronics, photonics, and other fields. Flow-limited field-injection electrostatic spraying (FFESS) is a solution-phase deposition technique suitable for vacuum-free and versatile processing thin-films and nanostructures. Through field-injection, FFESS charges solution-phase precursors to form multi-jets that disperse into charged nanodrops which coat substrates and produce the desired films. FFESS’s employment of solution-phase processing allows for facile control over materials stoichiometry and defect populations via molecular mixing while the usage of charged nanodrops allows for enhanced film crystallinities and morphologies at reduced substrate temperatures. These factors enable FFESS to be used for an extensive selection of applications where nano-scale control of material structure and properties is integral. In this work, FFESS is applied to a wide range of new applications including device processing and new materials systems. FFESS was used to produce highly Al-doped zinc oxide thin films, a cost-effective semiconductor which can be processed at reduced temperatures for improved substrate compatibilities. These films were used in vertical Schottky diodes which, using FFESSS as a multipurpose processing platform, were able to prepared rapidly, within 1 hour, and demonstrated comparable rectifying performance to diodes prepared by more time-consuming processes that require additional equipment. The FFESS methodology for zinc oxide was then modified to continuously prepare nanocrystal coatings which absorb mid-infrared light using localized surface plasmon resonances. By adjusting the conditions under which the nanocrystals were produced, the infrared absorption wavelength and intensity could be chosen based on application. FFESS was also used to prepare thin films from new materials systems which are highly sensitive to processing conditions and are easily destabilized. These include F-doped BaBiO3, a predicted topological insulator, and cubic-phase-pure formamidinium lead iodide, a photoactive material for use in perovskite solar cells. The effect of processing conditions and the materials properties of these films were investigated. These applications have demonstrated FFESS’s ability to bring solution-phase processing to new and growing fields and demonstrate FFESS’s capabilities as a powerful multi-purpose deposition technique.

Graduation Semester

2023-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Riley Vesto

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