Computational Spectroscopy for Nanoscale Photovoltaics

Nanoscale photovoltaic (PV) systems employ nanomaterial interfaces to dissociate bound excitons formed upon sunlight absorption. This mechanism results in a correlated electron, hole, and exciton interface dynamics whose accurate determination is challenging both theoretically and experimentally. In this talk, I will discuss approaches available to compute and combine relevant spectroscopic quantities to predict efficient nanoscale PV systems. Further, I will present our recent work on two novel families of nanoscale PV devices based on: 1) Nanocarbon materials, achieving 1.3\% efficiency, tunable infra-red optical absorption, and superior photostability compared to organic solar cells 2) Two-dimensional monolayer semiconductors such as Graphene-BN and MoS$_2$, capable of absorbing a significant fraction of sunlight within just $\approx10$nm, and showing tunable absorption, band offsets, and power conversion efficiency (PCE).\\[4pt] In closing, I will discuss the errors and necessary accuracy in predicting PCE from first-principles calculations, and propose a suitable figure of merit to quantify absorption solar-matchedness to be used in large-scale searches of nanoscale PV materials.