Multi-component Organic Materials: Multi-scale Modeling of the Impact of Molecular Aggregation and Mixing on Solar Cell Efficiency
Abstract
The University of Arizona proposes a four-year multi-scale computational research project, to becarried out in strong collaboration with experimental groups involved in the program, in order to: (i) provide a comprehensive description of how chemical structure impacts molecular-scale packing (self-aggregation and mixing) in the multi-component active layersof organic solar cells (OSCs); and (ii) describe how nano-scale interfacial aggregation or mixing governs exciton dissociation, charge separation, and charge recombination, in relation to meso-scale morphology. The results will aid the design of materials for more efficient OSCs, to be used for expeditionary power during Navy and Marine Corps operations. Specifically, the work will focus on:(1) Molecular description of nano- and meso-scale morphologies in OSC ternary active layers. All-atom and coarse-grained molecular dynamics simulations will be performed to establish the morphology at the nano-scale and meso-scale, respectively. Ternary systems with bulk-heterojunction and planar-heterojunction architectures and containing asymmetric acceptors will be considered. (2) Evaluationof the impact of the guest component on exciton dissociation and charge recombination in ternary OSCs. The electronic properties ofmolecular clusters extracted from the morphologies derived in Part (1) will be determined at state-of-the-art DFT level, which willallow the evaluation of the microscopic parameters impacting the charge and exciton transport pathways. Recently, it was suggested that the introduction of additional asymmetric acceptor molecules in ternary blends results in a combination of donor-acceptor intermolecular configurations that appears to provide the right balance between charge generation and charge recombination. The availability of ternary morphologies will allow the verification of this hypothesis by investigating the complex energetic landscape of the systems as well as todetail the effect of the additional asymmetric acceptor component on the system energetic disorder.(3) Evaluation of electron delocalization and electron polarization effects on charge separation in NFA OSCs. The focus will be on planar-heterojunction architectures whose interfacial morphologies will be evaluated through molecular-dynamics simulations. The extent to which the donor and acceptor and components mix at the interface will be directly related to the inter-molecular interaction parameters. Acceptor clusters of various sizes will be extracted from the molecular-dynamics simulations and will serve to analyze the impact of delocalization on the exciton and transport states. Here, quantum mechanics / molecular mechanics calculations will be performed to determine the role of electronic polarization on the energies of the charge-transfer and charge-separated states.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 24, 2024
- Source ID
- N000142412114
Entities
People
- Jean-Luc Brédas
Organizations
- Office of Naval Research
- United States Navy
- University of Arizona