| 초록 |
Kesterite-based thin-film solar cells (TFSCs) have gained growing attention in the photovoltaic (PV) sector for their elemental earth abundance and low toxicity. An inclusive study from the past reveals basic knowledge about the grain boundary (GB) and grain interior (GI) interface. However, the compositional dependency of the surface potential within GBs and GIs remains unclear. The present work highlights deep insights into the surface potential of the bulk and GB interfaces. The Sn composition is sensitive to the absorber morphology and, therefore, it significantly impacts absorber and device properties. Absorber morphology improves with the formation of larger grains as Sn content increases. Additionally, the presence of SnSe2 and increased [ZnCu + VCu] A-type defect cluster density was observed and validated through Raman analysis. The secondary ion mass spectroscopy analysis revealed, the altered distribution of sulfur and sodium with higher near-surface accusation. Thus, the synergistic outcome of the increased density of defects and the accumulation of S near the interface provides a larger GBs and GIs difference and expedites carrier separation improvement. Consequently, at an optimum compositional ratio of Cu/(Zn+Sn) = ~0.6, the power conversion efficiency (PCE) is significantly improved from 8–11%. |
