Using Simulations to Probe the Interfacial Disorder of Organic Solar Cells

Abstract

Solar cell technology is constantly evolving, pushing the limits of efficiency while working to conserve costs. Organic solar cells are promisingly inexpensive to make but are much more disordered than conventional materials, making them much less efficient. This disorder, which takes the form of traps, greatly influences the behavior of the carriers but is not fully understood. Understanding all the intricacies of this disorder would enable us to build more efficient devices. In a heterojunction organic photovoltaic device, the trap properties of the interface between the donor and acceptor materials can significantly impact the device efficiency but it is still unclear exactly how. We hypothesized that the trap properties of this interface impact the performance of the device more than the bulk properties and that there is more disorder in the interface than the bulk. We investigated our hypotheses using drift-diffusion simulations and found that while the interface does have more of an impact on the device than the bulk it is difficult to conclude if there is more disorder in the interface than the bulk.