Quantifying the Overall Efficiency of Circularly Polarized Emitters

An increasing number of circularly polarized luminescence (CPL) molecular emitters has been developed in recent years and many of them are intended for applications in which high overall CPL efficiencies are required. In order to have a complete picture of the efficiency of a CPL emitter, dissymmetry factor (g_lum) is not enough. In the following we propose a new quantity, named CPL brightness (B_CPL), which takes into account absorption extinction coefficient and quantum yield along with the g_lum factor. We calculated B_CPL value for more than 180 compounds reported in the literature and we analyse data distribution for the main classes of CPL molecular emitters. This tool can be employed to put into context new CPL active compounds and to direct the choice of molecular systems for specific CPL applications.