Structural and electronic information drawn from the circularly polarized luminescence spectra: Many questions and some answers for simple organic molecules, polymers, and molecular aggregates

In the last ten years, circularly polarized luminescence (CPL) has greatly advanced: Lots of data have been collected and many compounds have been synthesized with the aim of enhancing this chiroptical response. We review here a few aspects with illustrative examples. After examination of the relation of circular dichroism (CD) and CPL signals, we investigate how CPL can be used to probe environment: Aggregation phenomena or the presence of metal ions or pH variations. We also study the CPL of inherently dissymmetric chromophores and of metal complexes. We finally touch upon whether CPL originates from molecules or from aggregated inhomogeneous systems.