Circularly polarized coherent light-induced boosting of polymer solar cells photovoltaic performance

Abstract

Abstract We report a microscopic quantum theory which can be used to study circularly polarized light (CPL) induced singlet to triplet conversions in polymer solar cells (PSCs). We demonstrate that by properly adjusting CPL irradiation parameters, the photo-created singlet excitons can be efficiently converted into non radiative triplet excitons. The maximum singlet–triplet conversion ratio might be reached when the incident CPL frequency is chosen in such a way that the resonant optical excitation occurs between singlet and triplet states. In addition, we also illustrate that with varying CPL oscillating strength, the singlet–triplet conversion patterns behave as the Rabi oscillations and the steadily maintained triplet excitons. The electron-lattice coupling leads to the self-trapping of the excitons, which enhances the coherence between the electron’s and hole’s spin oscillations. This study opens up a novel approach for enhancing and controlling the photovoltaic response of PSCs by an effective all-optical route.