Providing power for miniaturized medical implants: triplet sensitization of semiconductor surfaces

Abstract

Here, we recognize the growing significance of miniaturized devices as medical diagnostic tools and highlight the need to provide a convenient means of powering such instruments when implanted into the body. One of the most promising approaches to this end involves using a light-collection facility to absorb incident white light and transfer the photonic energy to a tiny semiconductor embedded on the device. Although fluorescent organic molecules offer strong potential as modules for such solar collectors, we emphasize the promise offered by transition metal complexes. Thus, an extended series of binuclear Ru(II)/Os(II) poly(pyridine) complexes has been shown to be highly promising sensitizers for amorphous silicon solar cells. These materials absorb a high fraction of visible light while the Ru(II)-based units possess triplet energies that are comparable to those of the naphthalene-based bridge. The metal complex injects a triplet exciton into the bridge and this, in turn, is trapped by the Os(II)-based terminal. The result is extremely efficacious triplet-energy transfer; at room temperature the rate of energy transfer is independent of distance over some 6 nm and only weakly dependent on temperature.

Stepwise photoconversion of an artificial light-harvesting array built from extended BODIPY units

“…The use of artificial light-harvesting arrays to sensitize solar cells is at a very early stage of development [5][6][7] and it is not yet clear if such devices offer a genuine benefit compared to direct excitation of the semiconductor. Nonetheless, it is an interesting concept that merits proper exploration.…”

“…The process of electronic energy transfer (EET) has been used as the underlying methodology by which to engineer numerous analytical protocols, 1 chemical sensors, 2 bio-probes 3 and molecular machines. 4 Artificial light-harvesting devices, 5 as used to drive solar cells 6 and/or photochemical batteries, 7 also rely heavily on EET to channel photons to the desired location. For these latter systems to be viable, it is necessary that the highly efficient EET process is matched by exceptional stability under prolonged exposure to sunlight.…”

Dramatic Effect of Solvent on the Rate of Photobleaching of Organic Pyrrole‐BF2 (BOPHY) Dyes

“…Organicd yes continue to find practical applicationsi np hotochemicald evices, ranging from OLEDs [1] to dye-injection solar cells [2] and phosphorescent lighting strips. [3] Additional applications include such diverse materials as sunscreens, [4] selective probes [5][6][7] and bio-labels, [8,9] fluorescent markers, [10] solid-state pH indicators, [11,12] miniaturised power supplies for medical implants [13] and antiforgerym arkers. [14] Particular attention has been directed towards dyes that absorb and emit in the red region, this being of special significance for biological applications such as super-resolution microscopy.…”