An optimized structure for CdTe solar cells

In the last five years, the world record of CdTe thin film solar cell conversion efficiency has been increased from 16.5% to 21.0%. Most noticeable and dramatic efficiency improvement has been originated from the elimination of blue loss by using wider band gap n-window layer such as CdSO to replace the traditional n-CdS of band gap 2.4 Ev. In this work, we use CdSO as the new n-window layer and systematic computer simulation is used to investigate the influence of the conduction band offset between CdSO and CdTe layer, the thickness and the doping concentration of CdSO layer on the efficiency of the solar cell. Finally, a new optimized CdTe so lar cell with highest simulated efficiency is designed and the role of CdSO layer is clarified. Simulation results also suggest that the new structure can almost remove the blue loss.