Semiconductor-sensitized solar cells (SSSCs) are a promising
candidate for the next-generation of low-cost photovoltaic sources.
A thin layer of nanostructured semiconductor coated over the
surface of a mesoporous wide-gap oxide semiconductor (normally
TiO2) is employed in the SSSC as the light-harvesting absorber
[1e5]. An electrolyte fills the porous spaces between the
mesoporous oxide nanoparticles to complete the redox process.
SSSCs can be categorized into two types depending on the electrolyte
used: liquid-junction or solid-state (also referred to as
extremely thin absorber e ETA) solar cells [6]. The utilization of
semiconductor nanostructures as light sensitizers has the advantages
of: a tunable energy gap Eg due to the quantum-size effect
a large optical absorption coefficient and multiple
electron-hole pair generation by a single incident photon .
SSSCs are also commonly referred to as quantum dot-sensitized
solar cells (QDSCs) if the semiconductor nanoparticles exhibit the
quantum-size effect. To date, the most widely-studied semiconductor
sensitizers have been the binary metal chalcogenides