Reverse saturable absorption in C60-doped porous glasses studied by single- and double-pulse pump–probe experiments

Abstract

We investigate the nonlinear absorption of C60-doped porous sol-gel glasses by single- and double-pulse pump–probe experiments. We find that the reverse saturable absorption (RSA) of these samples can be explained in the frame of a five level system as it is commonly used for C60 solutions. We observe a strong saturation of the RSA at high fluences, especially if the molecules are prepared in the triplet state. In a double-pulse pump–probe experiment we measure the triplet quantum yield for C60 solutions (0.8) and doped glasses (0.25) and the singlet and triplet absorption cross sections. In the first excited singlet state (S1) lifetimes of 1 ns and 65 ps are determined in solutions and glasses, respectively. We find that the dynamics of both depopulation processes, direct S1–S0 relaxation, and intersystem crossing is faster in glasses than in the case where C60 is in solution in a liquid aromatic solvent. We tentatively explain these findings by the absence of a stabilizing solvent and a perturbation of the molecular energy levels due to interaction with the solid glass matrix. We finally determine the lifetime of the triplet states in our glass samples to 2 μs.

Photophysics and transient nonlinear optical response of donor–[60]fullerene hybrids

“…In addition, a five-level model has been employed to fit the experimental OL behaviour, as it has been suggested elsewhere. 45 The photophysical parameters of C 60 used in this model are those reported in ref. 45, while for the [60]fullerene dyads 1 and 2 the same values have been used as no other data are currently available in the literature to the best of our knowledge.…”

Picosecond optical limiting in reverse saturable absorbers: a theoretical and experimental study

“…This approach can be straightforwardly extended to the case of arbitrary initial conditions to study the absorption properties of the material by double pump-probe measurements. 25,26 Additionally, we can use the results of picosecond optical limiting experiments to determine material parameters that in turn can then be used to predict the outcome of nanosecond optical limiting. Fig.…”

Polyhedral oligomeric silsesquioxane bound fulleropyrrolidines

“…3, and exhibit an absorption band at 433 nm, and a broad band at approximately 705 nm due to the triplet-triplet absorption. These features are characteristic of [6,6] ring-closed fullerene derivatives, which exhibit a singlet-triplet quantum yield near unity, like C 60 . [22] Excitation of the fulleropyrrolidines (λ exc = 335 nm) displayed weak emission bands with maxima at approximately 719 nm (Fig.…”

“…[14 -17] It is not trivial to effectively covalently couple two such dissimilar nanoparticles, the fullerene and the silsesquioxane (POSS), as such compounds have not been previously reported in the literature. A widely accessible pathway to fullerene substitution is through generation of azomethine ylides in situ, via the reaction of an aldehyde and an amino glycine, followed by [6,6] cycloaddition to C 60 , to yield the desired fulleropyrrolidine, [18] the synthesis and characterization of which are the subject of this paper.…”