Numerical simulation of a bilayer organic solar cell based on boron chromophore compounds as acceptors

Abstract

Organic solar cells fabricated with non-fullerene acceptors have proven to be a solution to reduce manufacturing costs. Besides the material selection, another way to reduce such costs is by optimizing the properties of both the materials and the interfaces which in turn would contribute to enhance the solar cells efficiency. This can be done with numerical simulations. Among non-fullerene materials, boron chromophores are relatively stable and chemically versatile compounds which have been usually used as donors in solar cells. In this work, planar solar cells based on PTB7 and boron compounds are proposed and simulated but by using the latter as acceptors. Specifically, we show the functionality of our proposed devices by analyzing the variation of both the Lowest Unoccupied Molecular Orbital (LUMO) and the influence of the non-intentional doping of the boron compounds with regard to the photovoltaic parameters of the solar cells. The properties of the materials such as the dielectric constant, energy levels, and non-intentional doping are taken from literature. We show that there are optimal values for LUMO and doping concentration to maximize the device efficiency. The causes of this behavior are analyzed using band diagram simulations.