Coupling Design in the Direct Synthesis of AgBiS<sub>2</sub> Nanocrystal Inks for Efficient and Eco-friendly Photovoltaics.

Yuan, Lin; Gao, Linlin; Li, Yang; Lu, Kunyuan; Liu, Yang; Huo, Jiajing; Hu, Long; Zhang, Qing et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

Direct synthesis of conductive AgBiS<sub>2</sub> nanocrystal (NC) ink provides a promising platform for eco-friendly, low-cost optoelectronic applications. However, current synthesis relies on single thiol ligands to maintain colloidal stability, which severely impairs inter-NC charge conductivity and ultimately limits device photovoltaic performance. Here, we utilize butylamine (BA) to solubilize cationic precursors, followed by 3-chloro-1-propanethiol (CPT) to engineer the NC surface and interparticle packing. This method produces NCs with reinforced inter-NC coupling, while the surface-anchored CPT ligands can release Cl<sup>-</sup> ions upon thermal annealing to achieve superior surface passivation. As a result, the power conversion efficiency (PCE) of AgBiS<sub>2</sub> NC solar cells is improved from 8.91% to 9.82%, and unencapsulated devices retain more than 90% of the initial PCE after 3 months under ambient conditions. This work advances the potential of directly synthesized NC inks for high-performance and low-cost optoelectronic applications.