First-principles interpretation of core-level spectroscopy of photoelectrochemical materials and processes

We present two case studies of first-principles theoretical methods applied in conjunction with experimental core-level spectroscopy measurements to investigate the electronic structure and dynamical processes in molecular and interfacial systems relevant to photoelectrochemical (PEC) technologies. In the first [1], we study the core-level and valence spectroscopies of two zinc(II)-porphyrin based Donor-pi-Acceptor (D-p-A) [2] dyes using the occupancy-constrained excited electron and core-hole (XCH) [3] approach and time-dependent density functional theory (TDDFT) simulations. In the second, we use constrained DFT and TDDFT to interpret measured transient core-level shifts in time-resolved femtosecond x-ray photoelectron spectroscopy, investigating the dynamics of the electron injection process from a N3 dye molecule chemisorbed onto a ZnO substrate. These studies illustrate the utility of first-principles methods in guiding the design of better PEC materials. References: [1] Zegkinoglou, I et al, J. Phys. Chem. C, J. Phys. Chem. C, 2013, 117, 13357 [2] Yella, A. et al, Science 2011, 334, 629. [3] Prendergast, D and Galli, G; Phys. Rev. Lett. 2006, 96, 215502.