Enhanced circularly polarized luminescence dissymmetry of [Ru(bpy)3]2+ complexes in a 3D chiral framework: a study of transparent thin films

Abstract

Circularly polarized luminescence (CPL) plays an important role in the development of advanced optical devices. However, the design of CPL-active materials with a decent dissymmetry factor is still challenging. Here, we report CPL-active transparent thin films made from optically active ruthenium complexes [Ru(bpy)₃]²⁺ embedded in chiral inorganic frameworks. Due to the unique chiral-in-chiral combination, the obtained [Ru(bpy)₃][Zn₂(C₂O₄)₃] displays CPL activity with a dissymmetry factor of 5 × 10⁻³. The CPL measurements show that the luminescence dissymmetry factor can be effectively enhanced by one order of magnitude when an optically active [Ru(bpy)₃]²⁺ complex is incorporated into a chiral inorganic framework compared to its solution form. This study not only emphasizes the potential of constructing CPL-active thin films with coordination polymers but also points out the importance of introducing extra chiral environment to improve the CPL effect.