Semiconductor nanocrystal quantum dots as solar cell components and photosensitizers: Material, charge transfer, and separation aspects of some device topologies

Nanocrystalline wide band gap semiconductors photosensitized with semiconductor nanocrystal quantum dots have recently attracted increasing attention as promising photovoltaic devices. This Perspective addresses several issues related to the choice of nanocrystal materials for quantum dot sensitized solar cells, the methods of quantum dot deposition on mesoporous wide band gap semiconductor layers, and combinations of quantum dots and classical ruthenium dyes as panchromatic sensitizers. It further discusses charge transfer kinetics and electron recombination in quantum dot sensitized solar cells. An alternate emerging concept, a structure combining the latter with a quantum dot based Schottky junction solar cell, is also briefly reviewed. Together these areas offer ample scope for improvements making use of the specific advantages of semiconductor nanocrystals.