Simulation of Ternary Organic Solar Cells as a 3d Grid of Resistors and Photodiodes to Study the Effects of Morphology and Material Properties

We simulate ternary organic solar cells as a 3d grid of resistors and photodiodes to study how a secondary acceptor as a third material affects the overall blend to optimize for power output. We find that the Voc, voltage at zero current, of the donor and third material interfaces should be at least that of the primary system. When the thickness and third material conductivity are high, it is better for a secondary acceptor to stick to the main acceptor due to an asymmetry in current pathways. Otherwise, it is better to place the third material next to the donor to increase the amount of donor:acceptor interfaces. Our results are likely most applicable to the addition of fullerene acceptors into donor:NFA blends, since their potential benefits come from an increased charge mobility and morphology as opposed to increasing the overall absorption spectra.