A NUMERICAL SIMULATION FOR EFFICIENCY ENHANCEMENT OF CZTS BASED THIN FILM SOLAR CELL USING SCAPS-1D†

Abstract

In this paper we proposed a solar cell having model “Back Contact/CZTS/ZnCdS/ZnO/Front Contact”. CZTS is working as an absorber layer, ZnCdS as a buffer layer and ZnO as a window layer with back and front contacts. The Zn content was varied from 0% to 10% and bad gap was changed from 2.42 to 2.90 eV as described in the literature. The impact of this band gap variation has been observed on the performance of solar cell by using SCAPS-1D software. The efficiency was varied due to variation in bandgap of ZnCdS thin film layer. The simulation was carried out at 300 K under A.M. 1.5 G 1 Sun illumination. The energy bandgap diagram has been taken from SCAPS to explain the different parameters of solar cell. The effect of ZnCdS having different bandgap values was observed. Then the thickness of CZTS layer was varied to check its effect and hence at 3.0 μm gave the imporved efficiency of 13.83% roundabout. After optimization of CZTS layer thickness, the effect of working temperature was examined on the performance of solar cell. The absorption coefficient variation from 1·104 to 1·109 cm-1 caused major effects on the characteristics parameters of solar cell along with on J-V characteristics and Quantum Efficiency curve. At 1·109 cm-1 absorption coefficient the efficiency of solar cell boost up to 16.24%. This is the remarkable improvement in the efficiency of solar cell from 13.82% to 16.24%. After optimization of all parameters, simulation was run at 280 K, having CZTS thickness of 3.5 μm, with 10% content Zn in ZnCdS (2.90 eV), and absoption coefficient of 1·109, the model efficiency reached up to 17.6% with Voc of 0.994 V, Jsc 26.1 mA/cm2 and Fill factor was 71.4%.