Oh Jae Taek, Bae Sung Yong, Ha Su Ryong, Cho Hongjoo, Lim Sung Jun, Boukhvalov Danil W, Kim Younghoon, Choi Hyosung
Department of Chemistry and Research Institute for Convergence of Basic Sciences, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea.
Nanoscale. 2019 May 16;11(19):9633-9640. doi: 10.1039/c9nr01192g.
Lead-free, water-resistant photovoltaic absorbers are of significant interest for use in environment-friendly and water-stable thin film solar cells. However, there are no reports on the water-resistance characteristics of such photoactive materials. Here, we demonstrate that silver bismuth sulfide (AgBiS2) nanocrystal solids exhibit inherent water resistance and can be employed as effective photovoltaic absorbers in all-solid-state thin film solar cells that show outstanding air and moisture stabilities under ambient conditions. The results of X-ray photon spectroscopy (XPS) and X-ray diffraction (XRD) analyses show that there is no change in the chemical composition and crystal structure of the AgBiS2 nanocrystal solids after a water treatment. Based on these results, AgBiS2 nanocrystal solar cells are fabricated. These devices also do not show any drop in performance after a water treatment, confirming that the AgBiS2 nanocrystal solids are indeed highly water-resistant. In contrast, lead sulfide (PbS) colloidal quantum dot (CQD) solar cells show significant decrease in performance after a similar water treatment. Using XPS analysis and density functional theory (DFT) calculations, we confirm that the iodine removal and the surface hydroxylation of the water-treated PbS CQD solids are the primary reasons for the observed decrease in the device performance of the CQD solar cells.
无铅、防水的光伏吸收剂对于用于环保且水稳定的薄膜太阳能电池具有重大意义。然而，尚无关于此类光活性材料防水特性的报道。在此，我们证明硫化银铋（AgBiS2）纳米晶体固体具有固有的防水性，并且可以用作全固态薄膜太阳能电池中的有效光伏吸收剂，该电池在环境条件下表现出出色的空气和湿气稳定性。X射线光电子能谱（XPS）和X射线衍射（XRD）分析结果表明，经过水处理后，AgBiS2纳米晶体固体的化学成分和晶体结构没有变化。基于这些结果，制备了AgBiS2纳米晶体太阳能电池。这些器件在经过水处理后也没有表现出任何性能下降，证实了AgBiS2纳米晶体固体确实具有高度防水性。相比之下，硫化铅（PbS）胶体量子点（CQD）太阳能电池在经过类似的水处理后性能显著下降。通过XPS分析和密度泛函理论（DFT）计算，我们证实水处理后的PbS CQD固体中碘的去除和表面羟基化是观察到的CQD太阳能电池器件性能下降的主要原因。
