Solution-Processed, Inverted AgBiS<sub>2</sub> Nanocrystal Solar Cells
Dezhang Chen, Sunil B. Shivarudraiah, Pai Geng, Michael Ng, C.-H. Angus Li, Neha Tewari, Xinhui Zou, Kam Sing Wong, Liang Guo, Jonathan E. Halpert
Abstract
AgBiS2 nanocrystals are a promising nontoxic alternative to PbS, CsPbI3, and CdS quantum dots for solution-fabricated nanocrystal photovoltaics. In this work, we fabricated the first inverted (p–i–n) structure AgBiS2 nanocrystal solar cells. We selected spray-coated NiO as the hole-transporting material and used PCBM/BCP as the electron-transporting material. Combining transient photocurrent and photovoltage measurements with femtosecond transient absorption spectroscopy, we investigated the charge collection process on metal oxide/AgBiS2 interfaces and demonstrated that the NiO/AgBiS2 NC junction in the p–i–n configuration is more efficient for charge carrier collection. The fabricated p–i–n solar cells exhibited a 4.3% power conversion efficiency (PCE), which was higher than that of conventional n–i–p solar cells fabricated using the same sample. Additionally, inverted devices showed an ultrahigh short-circuit current (JSC) over 20.7 mA cm–2 and 0.38 V open-circuit voltage (VOC), suggesting their potential for further improvements in efficiency and, eventually, for large-scale production.