Chiral Plasmonic Nanocavities Enable Efficient Circularly Polarized Luminescence through Tailored Optical Chirality
Yong Li, Xuehao Sun, Honghan Ji, Yawen Li, Pengfei Duan, Qingfeng Zhang, Tao Ding
Abstract
Ultrastrong enhancement of circularly polarized luminescence (CPL) is achieved with chiral plasmonic nanocavities made of helicoid-on-mirror structures. The large local optical chirality enhancement, along with local electric field enhancement in the ultrathin chiral nanocavities, generates prominent chiral photoluminescence with a dissymmetric factor ( g lum ) of up to ∼0.6 and a quantum yield (QY) of ∼29%. Such a large chiroptic enhancement is correlated to the morphology of the helicoids, where the sharp corners strongly enhance the local E-field (∼500) and optical chirality (∼90). This chiral plasmonic nanocavity can also be applied to enhance the CPL of a chiral dye (R/S-1) with an emission band off the plasmon resonance, which leads to a 4-fold enhancement of its g lum (∼0.2) and QY up to ∼60%. This superior enhancement strategy not only demonstrates the synergistic enhancement of both QY and g lum but also provides a promising route toward superior CPL devices for practical applications.