Circularly polarized luminescence from pyrene excimers

Recently, many reports have emerged about circularly polarized luminescence (CPL) based on excimer emission of pyrenes. The intense CPL was observed from various pyrene derivatives such as pyrenes having chiral side chains, chiral oligomers bearing multiple pyrene rings, and pyrenes encapsulated by γ-cyclodextrins. The luminescence dissymmetry factor was found to be obviously higher than the absorption one in those pyrenes. In addition, several pyrenes revealed reversible “on-off” CPL switching upon the complexation/decomplexation of metal ions.