Laser and physical properties of BODIPY chromophores in new fluorinated polymeric materials

We report on the synthesis and photophysical and lasing properties of new linear and cross-linked fluorinated polymeric materials doped with two BODIPY chromophores such as PM567 and PM597. The total fluorine content of the matrixes was varied adding to methyl methacrylate (MMA) different volumetric proportions of monomers with increased number of fluorine atoms: 2,2,2-trifluoromethyl methacrylate, 2,2,3,3,3,pentafluoropropyl methacrylate (PFMA), and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate. The rigidity of the materials was modified adding to PFMA di-, tri-, and tetra-functionalized comonomers such as ethyleneglycol dimethacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate. When the fluorine-modified organic matrixes were transversally pumped at 532 nm, highly stable laser operation with high, not-optimized efficiencies up to 42% was obtained. The highest photostability was recorded for PM597 doped MMA/ PFMA 70/30 linear matrix, with no sign of degradation in the laser output after 500 000 pump pulses at 30 Hz, corresponding to an accumulated pump energy of 12 300 GJ/mol. The laser action depended more on the composition of the fluorinated comonomer than on the actual fluorine content with respect to the total weight of the matrix. Narrow line width operation with tuning ranges of up to 37 nm was obtained with both pyrromethene dyes when some of the samples were incorporated into a grazing incidence grating oscillator. Good correlations between the photophysical properties and the lasing behavior have been observed. The remarkable improvement in photostability exhibited by the fluorine-modified organic hold promise in the development of industrial oriented laser applications of organic solid-state materials.