| 초록 |
Fabrication of thin-film solar cells (TFSCs) based on the earth-abundant element is of prime importance in the PV sector to develop sustainable energy resources. The kesterite-based photoabsorber materials Cu2ZnSn(S, Se)4 (CZTSSe) TFSCs have gained the record power conversion efficiency (PCE) of 13.2%, which is still lower than CIGS. In this work, we offer insights into the surface potential of the bulk and GB interfaces. To study the effect of metallic composition ratio on carrier separation process, the tin (Sn) composition is varied. As the composition ratio varies, the absorber morphology improves with the growth of larger grains. Further, the change in the defect density observed with increases in Sn content, validated through Raman analysis. The secondary ion mass spectroscopy study demonstrated the altered distribution of sulfur (S) and sodium (Na) in CZTSSe thin films. The synergistic outcome of the increased density of defects and the accumulation of S near the interface provides a larger GB and GI difference and expedites carrier separation improvement. Subsequently, the device efficiency significantly improves from 6.42 to 11.04% with an open-circuit voltage (VOC) deficit of 567 mV. |
