Abstract

Photoelectrochemical cells are devices that can harness energy from the sun and do not need moving parts. These devices are environmentally friendly, noiseless, and nonpolluting. One of the components of a photoelectrochemical cell is a semiconductor layer. The dye-sensitized solar cell (DSSC) and the quantum dot-sensitized solar cell (QDSSC) are photoelectrochemical cells that convert energy from sunlight into electricity. In DSSCs and QDSSCs, the semiconducting layer is usually a metal oxide (MO). Apart from the MO semiconductor, which has its own role to play, metal chalcogenide semiconductors are used as sensitizers in QDSSCs. Examples of MO semiconductors used in DSSCs and QDSSCs include TiO₂ (Gratzel 2001), SnO₂ (Chappel and Zaban 2002), and ZnO (Zhang et al. 2009), whereas examples of sensitizers or quantum dots used in QDSSCs are CdS (Schaller and Klimov 2004), CdSe (Fuke et al. 2010), CdTe (Xiaoyan et al. 2014), and PbS (Lee et al. 2009, Ju et al. 2010) metal chalcolgenide semiconductors. Knowledge of the semiconductors is important especially for the design of photoelectrochemical cells with good performance. In this chapter, we focus on these materials and their application in DSSCs and QDSSCs.