Janus CsPbBr₃–AgBiS₂ Heteronanocrystals for High-Efficiency Photodetectors

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 3 –AgBiS 2 HNCs by in situ growth of CsPbBr 3 NCs on prepared AgBiS 2 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 3 to AgBiS 2 . The enhanced absorption range and exciton dissociation in 150 °C HNCs leads to photoconductors with drastically improved responsivity ( R of 183.8 A W –1 ) and specific detectivity ( D * of 5.0 × 10 14 Jones). This work not only provides a reliable method for combining ionic CsPbBr 3 and covalent AgBiS 2 but also has great potential for future practical applications, such as an NC (QD) solar cell.