Facile modified chemical precipitation approach for the synthesis of CuXIn1−XS2 nanocrystals and their application in high-performance CuXIn1−XS2/CdS co-quantum dots sensitized solar cells

CIS nanocrystals (NCs) have been applied in quantum dot-sensitized solar cells (QDSCs) as the light-absorbing layer. The value of bandgap energy and positions of conduction and valance band edges could be controlled by both size and composition of the nanocrystals. It is also Cd-free and can be synthesized with the hot-injection and usual aqueous chemical precipitation methods. Nevertheless, the hot injection method is carried out using the expensive and toxic materials and complicated experimental setups. Here we propose a facile chemical precipitation approach for the synthesis of CIS NCs. Then they have been utilized in the TiO 2 NPs/CIS/ZnS and TiO 2 NPs/CIS/CdS/ZnS photoanode structures of the conventional QDSCs. Different concentrations of thioglycolic acid as the capping agent and the reflux time were altered in a wide range to investigate the bandgap energy and dispersion/deposition of the synthesized NCs. The number of SILAR deposition cycles for the co-light absorbing CdS QDs film was also changed for better photovoltaic performance of corresponding QDSCs. TiO 2 hollow spheres (HSs) were finally applied to enhance the light scattering and absorption. The results demonstrated that the pioneer cell with TiO 2 NPs/TiO 2 HSs/CIS/CdS/ZnS photoanode including the CIS QDs synthesized in 60 min of the reflux time, 1M concentration of TGA and 2 CDs SILAR deposition cycles revealed a J sc = 22.93 mA/cm 2 , V oc = 581 mV, FF = 0.4 and power conversion efficiency of 5.31%. This PCE was improved about 83% and 43% compared to those of the reference cells with TiO 2 NPs/CIS/ZnS and TiO 2 NPs/TiO 2 HSs/CIS/ZnS photoelectrodes.