Bridging-Halogen Dependence of Ultrafast Dynamics of Excitons in Quasi-One Platinum Complexes

The femtosecond time-resolved luminescence of a quasi-one-dimensional halogen-bridged platinum complex [Pt(en)₂][Pt(en)₂I₂](ClO₄)₄ (abbreviated as Pt-I) is observed. The observed lifetime of the exciton luminescence is rather shorter than those of the other Pt-X (X = halogen ion) systems which have relatively wider band gaps. This result is considered to show that the nonradiative relaxation process becomes more efficient in the narrow-gap system Pt-I.