Selected I-III-VI(2) Semiconductors: Synthesis, Properties and Applications in Photovoltaic Cells

I–III–VI(2) group quantum dots (QDs) have attracted high attention in photoelectronic conversion applications, especially for QD-sensitized solar cells (QDSSCs). This group of QDs has become the mainstream light-harvesting material in QDSSCs due to the ability to tune their electronic properties through size, shape, and composition and the ability to assemble the nanocrystals on the surface of TiO(2). Moreover, these nanocrystals can be produced relatively easily via cost-effective solution-based synthetic methods and are composed of low-toxicity elements, which favors their integration into the market. This review describes the methods developed to prepare I-III-VI(2) QDs (AgInS(2) and CuInS(2) were excluded) and control their optoelectronic properties to favor their integration into QDSSCs. Strategies developed to broaden the optoelectronic response and decrease the surface-defect states of QDs in order to promote the fast electron injection from QDs into TiO(2) and achieve highly efficient QDSSCs will be described. Results show that heterostructures obtained after the sensitization of TiO(2) with I-III-VI(2) QDs could outperform those of other QDSSCs. The highest power-conversion efficiency (15.2%) was obtained for quinary Cu-In-Zn-Se-S QDs, along with a short-circuit density (J(SC)) of 26.30 mA·cm(−2), an open-circuit voltage (V(OC)) of 802 mV and a fill factor (FF) of 71%.