We demonstrate that photoactivated oxygen addition to diphenylanthracene moities can be used as a tool for protection of porphyrin's phosphorescence against oxygen quenching. Phosphorescent palladium(II) tetrabenzoporphyrin, covalently linked to four diphenylanthracene moieties, was synthesized and studied. Upon irradiation with ambient light or red laser in solution in air, addition of oxygen and formation of the corresponding endoperoxides were observed. Heating of the irradiated samples afforded the parent porphyrin material.
Solar energy storage and conversion is a key technology for the future realization of a sustainable energy production worldwide. The utilization of low-energy photons by means of upconversion (UC) processes has the main advantage of the upconversion process and solar energy-harvesting devices being considered and optimized independently, without affecting the particular physical characteristics of the operating sunlight excited material or device architectures. The UC-device must function efficiently with noncoherent light excitation, under light intensities comparable with those obtainable from moderate concentrated sunlight (1 to 20 suns, AM1.5); such a low degree of concentration allows usage of Fresnel-type focusing systems. We report chemical synthesis and efficient functioning of a triplet-triplet annihilation upconversion-based device, harvesting the entire deep-red spectral range of the sun irradiation (Δλ ∼ 142 nm) in a gap-free manner.
Fusion with a 9,10-anthraquinone moiety was achieved to extend porphyrin's π-system. A bridged dihydroisoindole derivative was used to prepare the corresponding meso-tetraphenyltetraanthraquinonoporphyrin (Ph4TAQP) via a thermal retro-Diels-Alder reaction. The basic optical properties of the prepared new anthraquinonoporphyrin and its complexes with Zn and Pd were studied.
Penetration and emanation
of light into tissue are limited by the
strong interaction of light with the tissue components, especially
oxygenated hemoglobin and white adipose tissue. This limits the possibilities
for all-optical minimal invasive sensing. In order to minimize the
optical losses of light in and out of the tissue, only a narrow optical
window between 630 and 900 nm is available. In this work, we realized
for the first time all-optical temperature sensing within the narrow
optical window for tissue by using the process of triplet–triplet
annihilation photon energy upconversion (TTA-UC) as a sensing tool.
For this, we apply the asymmetrical benzo-fused BODIPY dye as an optimal
emitter and mixed palladium benzo-naphtho-porphyrins as an optimal
sensitizer. The TTA-UC sensing system is excited with λ = 658
nm with an extremely low intensity of 1 mW × cm–2 and is factual-protected for a time period longer than 100 s against
oxygen-stimulated damage, allowing a stable demonstration of this
T-sensing system also in an oxygen-rich environment without losing
sensitivity. The sensing dyes we embed in the natural wax/natural
matrix, which is intrinsically biocompatible, are approved by the
FDA as food additives. The demonstrated temperature sensitivity is
higher than ΔT = 200 mK placed around the physiologically
relevant temperature of T = 36 °C.
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