Effect of bromination on the optical limiting properties at 532 nm of BODIPY dyes with p-benzyloxystyryl groups at the 3,5-positions

An analysis of the photophysical and optical limiting properties of a novel 1,3,5-tristyrylBODIPY dye

“…8a) is one of the key prerequisites for a material to be considered a good optical limiter. It is noteworthy that this curve does not achieve a plateau in terms of the output fluence (I out ) values at relatively low input fluence (I 0 ) values in contrast with what has been reported recently for solutions of 3,5distrylBODIPY dyes [34,37,39]. The limiting threshold intensity (I lim ) can be defined as the input fluence value at which nonlinear transmittance is reduced by 50% relative to the linear transmittance value (Fig.…”

“…However, when nanosecond pulses are used, the intrinsic value for b cannot be determined, and only an effective value (b eff ) is determined instead. As has previously been demonstrated to be the case with 3,5distyrylBODIPYs and 3,5divinyleneBODIPYs [34,[37][38][39], linear single photon absorption is likely to be a significant factor in populating the S 1 and T 1 excited states of 3 since there are significant nonzero linear absorption coefficient (a) values at 532 nm (Table 4).…”

“…In 2003, the optimal range of hyperpolarizability values was reported to be as low as the 10 -34 -10 -29 esu range for organic dyes in solution [79], so the values reported in Table 4 imply that these complexes possess superior nonlinear optical properties in a similar manner to 3,5distyrylBODIPY dyes [34,36,37,39] and that mixtures of 3,5di and 1,3,5tristyrylBODIPYs formed through Knoevenagel condensation reactions could potentially be used in OL applications without further purification. It should be noted, however, that considerably higher hyperpolarizability values have been reported for solutions of 3,5distrylBODIPY dyes recently at similar concentrations [34,37,39]. The addition of a third styryl group at the 5position complicates the introduction of push-pull properties aligned with the boronmesocarbon axis, which has been found to enhance the second order hyperpolarizability value.…”

“…Previously, there has been a strong focus on the nonlinear absorption (NLA) properties of phthalocyanines [24][25][26] and porphyrins [24,27], but until recently there were relatively few studies reported on the use of BODIPY dyes as optical limiters for 532 nm laser excitation pulses [28][29][30] and for those at other wavelengths [31][32][33]. Recently, we have demonstrated that BODIPY dyes with extended π systems at the 3,5positions are potentially suitable for use as optical limiters at 532 nm [34][35][36][37][38][39][40][41], since the extension of the π system shifts the main spectral bands into the 600-750 nm region, and this leads to relatively weak absorption at 532 nm under ambient light conditions.…”

2,6-Dibrominated 3,5-DistyrylBODIPYs as Photosensitizer Dyes for Photodynamic Antimicrobial Chemotherapy

“…The 1 H NMR spectra can be readily assigned since they are broadly similar to those reported previously for other 3,5-distyryl-, and 3,5-divinyleneBODIPY dyes. [29,[46][47][48][49][50] Peaks for the twenty-three aromatic region protons and six methyl protons of 3 can be readily identified in the 1 H NMR spectrum, and the parent peak derived by MALDI-TOF MS was found to be consistent with the anticipated molecular mass. As has been reported previously, [7] halogenation and styrylation result in red shifts of the main BODIPY spectral bands of 2 and 3, Figure 1 and Table 1.…”