Copper Indium Sulfide: Zinc Sulfide (CIS:ZnS) alloyed quantum dots as an eco-friendly absorbers in solar cells

Copper based multinary quantum dots solar cells (QDSSCs) attracted significant attention in last few decades as an inexpensive, harmless alternative to heavy metals based semiconducting materials. Copper indium zinc sulfide (CIS:ZnS) alloyed quantum dots (QDs) is the most interesting material among the other QDs because the entire visible spectrum can be effectively absorbed by these Co-based multinary quantum dots through the bandgap energy tunability. Synthesis and characterization of copper indium zinc sulfide (CIS:ZnS) quantum dots were carried out towards the fabrication of QDs-sensitized solar cells. By employing these inexpensive QDs as a photo-absorbers in solar cells, one can get rid from the expensive organic dyes for light absorption. The colloidal CIS:ZnS QDs were synthesized by inexpensive heat up method with capping ligand. The optical properties were analyzed through UV-Vis absorption and photoluminescence emission spectroscopy. The QDSSCs were fabricated using CIS:ZnS QDs loaded TiO₂ photoanode and copper sulfide as counter electrode. The photovoltaic performance of the fabricated QDs solar cells were analyzed by J-V characterization. The solar cells show the power conversion efficiency of ∼ 1.5 %. This is interesting because of utilization of inexpensive and environmentally benign QDs as photo-absorbers. The mean photovoltaic parameters of the fabricated solar cells were calculated from the J-V curve (Voc = 0.492, Jsc = 6.53, Fill factor = 0.46 and the average efficiency η= 1.5 %). (author)