Solution processed LiF anode modification for polymer solar cells

The indium-tin-oxide/active layer interface is critical to the performance of organic solar cell devices. In this study, submonolayer films of LiF nanoparticles are deposited on the electrode surface with the assistance of polymeric micelle reactors, with controlled nanoscale surface coverage. Incorporation of the solution-processed bi-layer electrodes into a conventional poly(3-hexyl-thiophene): [6,6]-phenyl C-61-butyric acid methyl ester device shows significant improvement in device performance, especially when used in combination with a poly(3,4-ethylenedioxythiophene: poly(styrene sulfonate) layer. The nearly 5x improvement in the short circuit current and decrease in the contact resistance is mostly likely related to the increase in surface work function from the use of LiF nanoparticles. The results strongly indicate that engineering of the interfaces is a useful tool for future device optimization. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729932]