2026-09-18T20:16:04Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/129638 2026-02-10 col_2142_5131 col_2142_14789 com_2142_5130 com_2142_14788 com_2142_8903

application/pdf en text Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01 The student, Kailyn Schueller, accepted the attached license on 2025-05-06 at 16:37. The student, Kailyn Schueller, submitted this Thesis for approval on 2025-05-06 at 16:42. This Thesis was approved for publication on 2025-05-07 at 13:33. DSpace SAF Submission Ingestion Package generated from Vireo submission #22238 on 2025-10-19 at 19:17:10 The impact of iron concentration on strontium titanate oxide materials as shown through ultrafast dynamics Schueller, Kailyn Marie 2025-05-07 Vura-Weis, Josh A. Photo-ionics Ultrafast Spectroscopy eng Understanding the ultrafast dynamics of photo-ionic materials such as Sr(Ti1-xFex)O3-x/2+δ will allow for the development of design principles of future photo-ionic materials. Optical transient absorption on a sub picosecond to few nanosecond timescale was performed on a series of different iron content in Sr(Ti1-xFex)O3-x/2+δ. Several experimental parameters had to be checked in order to get the most accurate excited state spectra. These included the fluence of the light, the wavelength of excitation, and samples prepared in different ways. After evaluating each of these conditions, excited state spectra of six samples ranging from an iron content of 4% to 35% were studied with an excitation wavelength of 340 nm and a fluence of 0.7 mJ/cm2. The excited state spectra of the series differs qualitatively between the low vs high iron content. All of the excited state spectra show features from band gap renormalization and free carrier absorption. On the timescale studied in this experiment, longer lived excited states are correlated with lower iron content. 2025-05 Text https://hdl.handle.net/2142/129638 Copyright 2025 Kailyn Schueller Chemistry Chemistry University of Illinois Urbana-Champaign M.S. Thesis