Janus CsPbBr<sub>3</sub>-AgBiS<sub>2</sub> Heteronanocrystals for High-Efficiency Photodetectors.

Qiu, Hengwei; Ji, Yongqiang; Hu, Wenfan; Liu, Feiyang; Jia, Donglin; Zhang, Lin; Lv, Xiaojun; Li, Meicheng · Nano Lett · 2025

basic_science · Level V

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Abstract

Heteronanocrystals (HNCs) composed of colloidal lead halide perovskites and chalcogenides always offer unique photoelectric properties. Nevertheless, synthesizing perovskite-chalcogenide HNCs has been a tough challenge due to their completely different growth dynamics. Here, we present an effective strategy to synthesize Janus CsPbBr<sub>3</sub>-AgBiS<sub>2</sub> HNCs by in situ growth of CsPbBr<sub>3</sub> NCs on prepared AgBiS<sub>2</sub> quantum dot (QDs). The as-synthesized HNCs show a large range of absorption characteristics from visible to near-infrared (NIR) wavebands. Femtosecond transient absorption (TA) spectroscopy reveals the transfer of both electron and hole from CsPbBr<sub>3</sub> to AgBiS<sub>2</sub>. The enhanced absorption range and exciton dissociation in 150 °C HNCs leads to photoconductors with drastically improved responsivity (<i>R</i> of 183.8 A W<sup>-1</sup>) and specific detectivity (<i>D</i>* of 5.0 × 10<sup>14</sup> Jones). This work not only provides a reliable method for combining ionic CsPbBr<sub>3</sub> and covalent AgBiS<sub>2</sub> but also has great potential for future practical applications, such as an NC (QD) solar cell.