Effect of Buffer Layers Cu<sub>2</sub>O and KF Between Molybdenum and CIGS in the Electrical Parameters of CIGS Thin Film Solar Cells

In this paper we have study the AZO/ZnO/CdS/CIGS/Mo/SLG heterojunction. We have study precisely the effect of Cu<sub>2</sub>O insertion between CIGS layer and Mo left contact. For this, we fix the Cu<sub>2</sub>O thickness at 100 nm. After this, we replace Cu<sub>2</sub>O by KF material with the same thickness. The use of those materials is motivated by their photovoltaic properties, their metallic content but also their non toxicity compared to PbS. By using SCAPS_1D software we have stimulated the effect of those buffer layers materials in electrical parameters as efficiency of solar cell, file factor, open-circuit voltage and short-circuit current density. Then, the efficiencies are around 24, 64% and 24.80% respectively for Cu<sub>2</sub>O and KF. We note that the efficiency increases at 21% to 24%. This introduction allows to establish a record efficiency for this kind of structure We note the same behavior for the file factor at 78.91% to 79.74% and 80.10% respectively for Cu<sub>2</sub>O and KF. These high electrical performances have obtained by using an Aluminum left contact and Molybdenum back contact. The functional temperature variation allows to obtain 26.20% and 25.99% efficiency for KF and Cu<sub>2</sub>O at 278.16 K. This functional temperature variation shows that by using phase change materials, we can attempt a record efficiency of 26%. This result is an improvement of 2% compared to ambient temperature. At the same time, this study shows that we have a big photovoltaic potential in the winter and in temperate area, near the pole area. This allows to find more recoiling technologies in order to improve more the efficiency of photovoltaic solar cells.