Investigating Electronic structure at Nano-Bio Interface to optimize Excitonic Solar cell architecture

A study of the Bacteriorhodopsin/TiO₂ and Bacteriorhodopsin/Perovskite interfaces associated with the photoactive chromophore in bacteriorhodopsin (bR) and its various mutant (D96N, triple glutamic mutations E9Q/E194Q/E204Q) forms allowed the explanation of the effective coupling existing between the π electrons of the chromophore and the local environment of the Schiff base when adsorbed to a substrate (Das et al., ACS applied materials & interfaces 11.34 (2019)). X-ray Photoemission Spectroscopy (XPS) and X-ray Absorption Spectroscopy (XAS) experiments have been used to explain some of the optical properties for various substrates such as Mesoporous TiO₂ and Perovskite. Density functional calculations (DFT) for both the ground state and the excited state has been carried in parallel with the experimental measurements. We discussed how to compensate the charge offset, to restore the Valence Band and XPS of C1s while mapping the occupied and unoccupied states around both sides of the Fermi level. In specific, we calculated the electronic band structure of the bR Chromophore using DFT+U methodology. The goal of this investigation is to optimize future Solar cell architecture (Das et al., The Journal of Physical Chemistry C (2019)).