Ultrafast dynamical study of self-trapped excitons in ladder type of halogen-bridged Pt complexes

• Published in: Journal of luminescence Vol. 128; no. 5; pp. 1081 - 1083
• Main Authors: Suemoto, Tohru, Takahashi, Youtarou, Yasukawa, Keizo, Kawakami, Daisuke, Takaishi, Shinya, Yamashita, Masahiro, Kobayashi, Atsushi, Kitagawa, Hiroshi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-05-2008; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Halogen-bridged; One-dimensional; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; Self-trapped exciton; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter; Ultrafast luminescence spectroscopy; One-dimensional; Halogen-bridged; Ultrafast luminescence spectroscopy; Self-trapped exciton; Self trapping; Stokes shift; Photoluminescence; Oscillations; Phase locking; Excited states; Ultrafast optics; Wave packets; Excitons; Charge density waves; Bromo complex; Iodo complex; Platinum complexes
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2007.11.004

The properties and the dynamics of the excited states in out-of-phase ladder-type halogen-bridged Pt complexes (Pt–Br-out and Pt–I-out) are studied using femtosecond luminescence spectroscopy. In both materials, Gaussian-shaped broad luminescence bands with large Stokes shifts are found around 0.8
eV and assigned to self-trapped excitons (STE). The wave-packet oscillations with periods of 290 and 306
fs were observed in Pt–Br-out and Pt–I-out, respectively. The higher oscillation frequency in Pt–I-out compared with the one-dimensional (1D)-type Pt–I is ascribed to the smaller lattice relaxation in the ladder system. Although the lifetime of the STE is almost the same as that of the 1D-type Pt–Br, the lifetime in Pt–I-out is one order of magnitude longer than that in the 1D-type Pt–I. This is ascribed to the phase locking of the charge density wave due to the interchain interaction.