The need to produce renewable energy with low production cost is indispensable in making the dream of avoiding undue reliance on non-renewable energy a reality. The emergence of a third-generation photovoltaic technology that is still in the infant stage gives hope for such a dream. Solar cells sensitized by dyes, quantum dots and perovskites are considered to be third-generation technological devices. This research focuses on the development of suitable and reliable sensitizers to widen electromagnetic (EM) wave absorption and to ensure stability of the photovoltaic system. This article discusses the basic principles and the progress in sensitized photovoltaics.
Part of the book: Nanostructured Solar Cells
Two types of third-generation photovoltaic (PV) cells are sensitized by dyes and quantum dots (QDs), the former being dye-sensitized solar cell abbreviated as DSSC. The second is the quantum dot-sensitized solar cell or QDSSC. There are three main components in DSSC and QDSSC. The photoanode is the component where the light is being absorbed either by molecules of the dye or by the quantum dots (QDs). The sensitizers are attached on the semiconductor (normally TiO2) surface. The conduction band (CB) of the semiconducting material should be at a level lower than the lowest unoccupied molecular orbital (LUMO) of the dye molecules or CB of QDs for fast electron transfer. Incorporation of plasmonic materials into the photoanode can increase light absorption efficiency by surface plasmon effect and thus improve the efficiency of the DSSCs and QDSSCs. Plasmonic materials that have been employed include gold (Au), silver (Ag) and aluminum (Al) nanoparticles (NPs). Different NPs exhibit different effects on the cell parameters. Covering the NPs with a thin wide bandgap semiconducting film is necessary to protect the plasmonic NP materials from the corrosive nature of the electrolyte.
Part of the book: Plasmonics