ScholarWorks@중앙대학교

초록

Silver bismuth sulfide (AgBiS2) is a promising, non-toxic, and earth-abundant photoabsorber with an appropriate bandgap for sustainable photovoltaic applications. A comprehensive understanding of solvent interactions within precursor chemistry is essential for optimizing film quality and enhancing the photovoltaic performance of solution-based AgBiS2 devices. In this study, we investigate the coordination behavior within the Bi(NO3)3·5H2O-thiourea-DMSO-AgNO3 system, emphasizing the effects of precursor sequence engineering. While the coordination between thiourea and metal ions is well established, we report the coordination of dimethyl sulfoxide (DMSO) to metal ions in the AgBiS2 molecular precursor ink system for the first time. Following that, we examine how such coordination influences film morphology and photovoltaic efficiency. The introduction of Ag+ ions prior to Bi3+ ions (Sequence 2) promotes uniform cation distribution, mitigates excessive Bi–S coordination, and enhances film quality, contrasting with the Bi3+-first addition approach (Sequence 1), which results in inferior photoelectric properties. Devices fabricated using Sequence 2 exhibit a power conversion efficiency (PCE) of 2.11%, outperforming the 1.12% PCE observed for Sequence 1, alongside increased current density and more efficient charge transport. These findings underscore the critical role of solvent coordination modulated by precursor mixing order in the design of high-quality films for solution-processed metal chalcogenide and halide photovoltaic systems.

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