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

• Published in: New journal of physics Vol. 22; no. 10; pp. 103034 - 103039
• Main Authors: Zhang, Longlong, Hao, Yuying, Qin, Wei, Xie, Shijie, Qu, Fanyao
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.10.2020
• Subjects: Circular polarization; circularly polarized light; Coherent light; Conversion ratio; Electron spin; Excitons; Oscillations; Photovoltaic cells; Physics; Polarized light; polymer solar cell; Polymers; Quantum theory; Solar cells; triplet exciton
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/abbf22

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.