Investigation of Charge Carrier Lifetimes in Functionalized Photoelectrodes for CO2 Reduction

The immobilization of molecular catalysts onto light-absorbing semiconductor surfaces is a promising strategy for solar fuel generation, as it allows for both the stability of heterogenous surfaces and the tunability of molecular catalysts. These so-called “hybrid photoelectrodes” integrate catalysts with photon capturing and charge separating materials to advance the light-driven generation of liquid fuels from CO₂ and H₂O. The research in this thesis quantifies the presence of surface-based defects (herein called trap states) for a series of functionalized p-type silicon surfaces using time-resolved infrared spectroscopy (TRIR) and correlates recombination rate constants with observed performance metrics of photoelectrodes. By comparing the recombination rate constants and photoelectrode performance, our understanding of the relationship between surface defects introduced by photoelectrode functionalization and catalyst performance will be advanced.