Metal‐Enhanced Circularly Polarized Luminescence of Self‐Assembled Au@SiO₂ Triangular Nanoprisms and Fluorophores in Chiral Cellulose Nanocrystal Films

Abstract Amplification of the intensity and dissymmetry factors (g_lum) of circularly polarized light is desired to broaden the range of applications of circularly polarized luminescence (CPL) because of the small g_lum values commonly observed for CPL materials and the loss of intensity resulting from circular polarization. In this study, enhanced CPL produced by metal‐enhanced fluorescence is successfully achieved by the self‐assembly of Au@SiO₂ triangular nanoprisms (Au@SiO₂TNPs) and fluorophores (sulforhodamine 101 and methylene blue) in chiral cellulose nanocrystal films. By overlapping the plasmon bands of Au@SiO₂TNPs and the excitation–emission spectra of fluorophores, both the fluorescence intensity and g_lum value of CPL are significantly enhanced. For sulforhodamine 101 in the metal‐enhanced CPL system, a 52‐fold fluorescence enhancement is achieved, and the g_lum value increased from −0.038 to −0.126. For methylene blue in the metal‐enhanced CPL system, a 201‐fold enhancement of fluorescence is obtained, and the g_lum value is enhanced from −0.055 to −0.085. This metal‐enhanced CPL film is expected to generate superior circularly polarized light for extensive CPL applications because of its outstanding enhanced CPL, fluorescence amplification, and feasibility for different fluorophores.