Abstract
A theoretical analysis of the optical and recombination losses effect on the performance of the solar cell with the structure ZnO:Al/CdS/CIGS/Mo/Glass has been accomplished in this work. All the results are carried out on the basis of the variation of Ga- ratio and the low thickness of the absorber layer ranged from 250 nm to 1 mu m. The optical parameters (refractive index, extinction coefficient and energy gap) resulting from the experimental investigation of the used materials are the base to calculate the optical losses caused by the reflection at different interfaces and absorption in ZnO:Al and CdS layers. The calculations of the recombination losses at the front and back surface of CIGS are carried out on the basis of some physical parameters of CIGS layer. The effect of antireflection coating layer and the reflectivity from back contact have been studied to improve the performance of CIGS solar cell. The results show that Ga- ratio of 0.3 has the maximum short-circuit current density of 16.46 mA/cm(2) and at the same time this ratio represents optical losses of about 35 %, these losses have been increased up to 59.5 due to non-absorption losses. It is found that the thickness of CIGS layer has a significant effect on the performance of this solar cell. Under the consideration of antireflection layer, reflectivity from back contact and at certain parameters of the absorber layer, the recorded efficiency of thin- film CIGS solar cell reached a value of 18.12%.