Nonlinear plexcitons: excitons coupled with plasmons in two-photon absorption. Issue 19 (9th May 2022)

• Record Type: Journal Article
• Authors: Chen, Yichuan; Cheng, Yuqing; Sun, Mengtao
• Is Part Of: Nanoscale. Volume 14:Issue 19(2022)
• Page Start: 7269
• Page End: 7279
• Publication Date: 2022-05-09
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d1nr08163b
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : The strong excitons of donor–acceptor system in two-photon absorption are strongly enhanced by local surface plasmon resonance excited by two-photon, which reveals strong nonlinear plexciton properties. Abstract : The nonlinear optical properties of a D–A (donor–acceptor) conjugated organic molecule with polythiophene (PT) as the donor and indene-C60 bisadduct (IC60 BA) as the acceptor are theoretically investigated, which exhibits a large two-photon absorption (TPA) cross-section up to 8000 GM at the wavelength of 780 nm. Combining surface plasmon resonances (SPRs) with nonlinear optics, nonlinear properties can be strongly enhanced. In this paper, an appropriate nonlinear plexciton method by the coupling of Au@Ag nanorods and an Ag film is designed, in which the TPA properties of the PT:IC60 BA complex can be increased by 10 6 times. The angle dependence on polarization and incidence is investigated to obtain the maximum of plasmonic enhancement. Our results emphasize the physical mechanism of nonlinear plexcitons and provide a feasible method to improve the nonlinear properties of organic solar cell materials.