Files
Abstract
The functionality and performance of many natural or artificial light-absorbing materials are determined by the behavior of photogenerated electrons and holes. Photovoltaic and photocatalytic systems rely on extracting these charge carriers to provide current in electrical circuits or to initiate oxidation and reduction processes, respectively. In photovoltaic or photocatalytic systems design, emphasis is placed on maximizing charge separation efficiency to extract electrons and holes. For photochemical processes, rate-determining mechanisms for crucial reactions involving photodissociation, isomerization, or energy transfer typically occur on sub-picosecond timescales after promoting electrons to excited states. Subsequent radiative or non-radiative relaxation is accompanied by structural transformations that are integral to photochemistry. In this work, versatile time-resolved spectroscopy techniques, Femtosecond Transient Absorption Spectroscopy (TAS), and Femtosecond Stimulated Raman Spectroscopy (FSRS) are applied to heterostructured copper oxide thin films, solution-phase photo-Oxa-Dibenzocyclooctyne (photo-ODIBO), and ODIBO towards understanding the photoinduced ultrafast responses in these samples. Random-phase and Bilayer heterostructure TAS studies were recorded to extract interfacial charge transfer contributions to Cu2O/CuO carrier dynamics. Evidence of picosecond charge transfer lifetimes in both random-phase and Bilayer heterostructures were then extracted by Global Lifetime Analysis of the time-resolved spectra. Additionally, Sub-294 fs excited state dissociation of photo-ODIBO and formation of an excited state of the product was revealed by complimentary 321 nm TAS and short pulse (45 fs) FSRS. Alternatively, photodecarbonylation with 350 nm excitation occurred via an intermediate on > 35 ps timescales. Details of our home-built TAS and FSRS spectrometers used for these studies are also addressed.