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%.