Because of their strong nonlinear optical properties, Platinum(II) acetylides are investigated as potential chromophores
for optical power limiting (OPL) applications. The strong excited state absorption and efficient intersystem
crossing to the triplet states in these materials are desired properties for good OPL performance. We
recently reported on OPL and photo-physical properties of Pt(II)-acetylide chromophores in solution, modified
with thiophenyl or triazole groups. [R. Westlund et al. J. Mater. Chem. 18, 166 (2008); E. Glimsdal et al.
Proc. SPIE 6740, 67400M (2007)] The chromophores were later incorporated into poly(methyl-methacrylate)
(PMMA) glasses. A variety of doped organic solids were prepared, reaching concentrations of up to 13 wt% of
the guest molecule. Raman spectra of the doped solid devices proved that the chemical structure of the nonlinear
dyes remains intact upon the polymerization of the solid matrix. Luminescence spectra confirm that the basic
photo-physical properties (absorption, emission and inter-system crossing) observed for the solute molecules in
THF are maintained also in the solid state. In particular, the phosphorescence lifetime stays in the order of μs to
ms, just as in the oxygen evacuated liquid samples. Also, the wavelength dependence and time-dynamics of the
triplet absorption spectra of the dyes, dissolved in THF solution and dispersed in solid PMMA matrices, were
investigated and compared. Ground state UV absorption spectra between 300 and 420 nm have corresponding
broad band visible triplet-triplet absorption between 400 and 800 nm. The triplet state extinction coefficients
were determined to be in the order of 104 M-1cm-1.