First-principles modeling of charge transfer in fullerene organic photovoltaics
EMSL Project ID
47707
Abstract
Organic photovoltaics have emerged as an inexpensive alternative to more traditional solar energy. Organic solar cells have long utilized fullerene derivatives as electron acceptors in devices, little is known about what specifically makes particular fullerenes candidates for devices than others. We therefore seek to calculate electron transfer rates in a large number of fullerene derivatives, the majority of which have merely been proposed, to determine which types of fullerenes make ideal devices. One particular difficulty in calculating transfer rates in fullerenes is that the asymmetry in dimer systems typically induces an artificial bias in the system due to the fact that there are only two fragments. To overcome this difficulty, we have developed a method whereby we apply a field to the DFT-generated Fock matrix to eliminate the bias and mimic the bulk. We are then able to calculate the transfer rates using Marcus theory. The main bottleneck in these calculations is generating the Fock and overlap matrices from DFT. Due to the size of the systems, over 200 atoms and several thousand basis functions, DFT calculations are very expensive. Because we seek to scan a very large number of molecules in a high-throughput fashion, using the NWChem on Chinook is essential. We will both to apply our method to get a better understanding of what makes particular solar cells better than others, as well as use it to predict which fullerenes will perform better in actual devices.
Project Details
Project type
Exploratory Research
Start Date
2012-12-03
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Aguirre JC, CD Arntsen, S Hernandez, R Huber, AM Nardes, M Halim, D Kilbride, Y Rubin, SH Tolbert, N Kopidakis, BJ Schwartz, and D Neuhauser. 2013. "Understanding Local and Macroscopic Electron Mobilities in the Fullerene Network of Conjugated Polymer-based Solar Cells: Time-Resolved Microwave Conductivity and Theory." Advanced Functional Materials. doi:10.1002/adfm.201301757
Arntsen CD, R Reslan, S Hernandez, Y Gao, and D Neuhauser. 2013. "Direct Delocalization for Calculating Electron Transfer in Fullerenes." International Journal of Quantum Chemistry 113(15):1885–1889. doi:10.1002/qua.24409