Light-Addressable Assemblies

The concept of light addressable potentiometric sensors (LAPS) was introduced in 1988 [67], LAPS is a semiconductor-based sensor with either electrolyte-insulator-semiconductor (EIS) or metal-insulator-semiconductor (MIS) structure, respectively. Figure 4.13 illustrates a schematic representation of a typical LAPS with EIS structure. A semiconductor substrate (silicone) is covered with an insulator (Si02). A sensing ion-selective layer, for instance, pH-sensitive S3N4, is deposited on top of the insulator. The whole assembly is placed in contact with the sample solution. 

Siqueira, Jr., J.R., Werner, C.F., Backer, M., Poghossian, A., Zucolotto, V., Oliveira, Jr., O.N., Schoning, M.J. Layer-by-Layer Assembly of Carbon Nanotubes Incorporated in Light-Addressable Potentiometric Sensors. J. Phys. Chem. C 113, 14765-14770 (2009)... 

As illustrated by nature and shown schematically in Fig. 4, an artificial photosynthetic system will require several molecular components that are spatially juxtaposed to favor the various tasks at hand, i.e., light harvesting, charge separation, catalysis for HER and OER. This next section will cover some of the molecular dyads, triads and larger assemblies prepared to address some of these challenges. 

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