Emerging Plasmon-Optical and -Electrical Effects in Organic Solar Cells: A Combined Theoretical and Experimental Study

Abstract

The imbalance of the optical photon absorption length and electrical exciton diffusion length in organic materials has set an upper limit of the active layer thickness around two hundred nanometers, resulting in the insufficient photon absorption of organic solar cells (OSCs). The high-efficiency OSCs need to address the above issues, and it is vital to introduce light manipulations for enhancing the optical photon absorption of the active layer (~200 nm), which is electrically thick but optically thin. The plasmonic effects of metal nanostructures facilitating the strong light-matter interactions have emerged as a promising tool for enhancing the light absorption of active layer due to its capability of amplifying the light intensity up to ten even hundred times in the subwavelength region. In this Chapter, we will briefly review the mechanisms of two types surface plasmon polaritons (SPPs) and their applications in enhancing the OSC efficiency. Regarding the narrow band feature of metal plasmonic resonances, we offer the design rules toward the wideband plasmonic resonances. The plasmon-optical effects with multiple plasmonic resonances are used to enhance the active layer absorption in whole visible region. Besides the plasmon-optical effects, the plasmon-electrical effects of the metal nanostructures, which are emerging as the interestingly hot topics, will be studied. Finally, the simultaneously plasmon-optical and -electrical effects induced by plasmonic asymmetric modes will be introduced and realized in single OSC device for boosting its performance. This Chapter devotes to provide an in-depth understanding of utilizing the plasmon-optical and -electrical effects for high-performance OSCs.