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Interfacial Electron Transfer in p-Type Dye-Sensitized Nickel Oxide and Machine Learning for Energy Materials

Yu, Yongze, Yu
http://orcid.org/0000-0001-8861-5322
http://rave.ohiolink.edu/etdc/view?acc_num=osu1564756409299145

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Chemistry.
Given the increasing worldwide need for energy consumption, the demand for the development of renewable energy conversion and storage becomes urgent and significant. Solar cells and solar fuels, which capture solar energy and convert into electricity and valuable chemical fuels, have been investigated for several decades. Dye-sensitized semiconductor electrodes and organic-inorganic hybrid perovskite (OIHP) materials have attracted much attention in various fields, such as physical science, chemical science, and material science. Interfaces play expressly important roles in energy material composites and optoelectronic devices. The insights gained through understanding the physical and chemical processes involved with the electron transfer that takes place at the energy material interfaces facilitates efficient progress and development. The principal focus of my graduate research was on the following aspects: (1) applying multiple advanced characterization techniques, with an emphasis on time-resolved spectroscopy (TRS) and electrochemical impedance spectroscopy (EIS), to investigate the spatial arrangement and energetic alignment of materials on interfaces; (2) combining computational tools like density functional theory (DFT) and molecular dynamics (MD), and (3) developing and applying data analytics tools such as kinetic modeling and machine learning (ML) to digest the physical insights, like electron transfer and complex surface phenomenon. In this dissertation, the photophysical properties of the BH series, a series of triphenylamine (TPA)−oligothiophene−perylenemonoimide (PMI) molecules, and corresponding sensitized semiconductor electrodes are presented. Through DFT calculations and TRS techniques, it is demonstrated that, upon photoexcitation, the BH molecules in solution undergo ultrafast intramolecular charge transfer within one picosecond. The charge-separated state then recombines within tens of picoseconds. When BH molecules self-assemble on the p-type semiconductor NiO, the electron transfer kinetics exhibit both fast and slow charge recombination processes up to several microseconds. Furthermore, when BH assembles on the semiconductor surface, it was found that excimer formations of BH assemblies develop due to the π−π interaction of the PMI units between the neighboring molecules. To the best of our knowledge, this is the first experimental observation of intermolecular excimer formation when conjugate donor-acceptor molecules form a self-assembled monolayer. Long-lived intermolecular charge separation is observed, and a new excimer-mediated intermolecular charge-transfer mechanism is proposed. Moreover, with the natural hydrophobicity of molecules and the interaction among nearby molecules, the assembledA the monolayer enables separation of the electrode from the aqueous electrolyte. Therefore, the band edge of the semiconductor can be decoupled with respect to the pH changes via an investigation using EIS and MD simulation. With this new insight of photo-physics of BH sensitized electrodes, a novel n-i-p sandwich electrode has been applied toward the production of solar fuels. Lastly, with the boom in OIHP material research, a surface phenomenon that occurs in the OIHP fabrication process has been studied via a cut-edging technique: ML. ML was utilized to study the trend in the compatibility of different amines, which is used in the post-treatment process for OIHP films. ML models were constructed from the classifications of these amines and their molecular descriptor features. Physical and chemical insights were obtained through an analysis of the constructed models.
Yiying Wu (Advisor)
Claudia Turro (Committee Member)
Bern Kohler (Committee Member)
209 p.
Chemistry; Physical Chemistry
Interfacial Charge Transfer; Dye-Sensitized NiO; Machine Learning in materials; Spectroscopy Modeling; SAM;

Recommended Citations

Citations

  • Yu, Yu, Y. (2019). Interfacial Electron Transfer in p-Type Dye-Sensitized Nickel Oxide and Machine Learning for Energy Materials [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1564756409299145

    APA Style (7th edition)

  • Yu, Yu, Yongze. Interfacial Electron Transfer in p-Type Dye-Sensitized Nickel Oxide and Machine Learning for Energy Materials. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1564756409299145.

    MLA Style (8th edition)

  • Yu, Yu, Yongze. "Interfacial Electron Transfer in p-Type Dye-Sensitized Nickel Oxide and Machine Learning for Energy Materials." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1564756409299145

    Chicago Manual of Style (17th edition)

osu1564756409299145
368
© 2019, some rights reserved.Creative Commons License Interfacial Electron Transfer in p-Type Dye-Sensitized Nickel Oxide and Machine Learning for Energy Materials by Yongze Yu Yu is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.