Janus CsPbBr<sub>3</sub>–AgBiS<sub>2</sub> Heteronanocrystals for High-Efficiency Photodetectors
Hengwei Qiu, Yongqiang Ji, Weiyan Hu, Feiyang Liu, Donglin Jia, Lin Zhang, Xiaojun Lv, Meicheng Li
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 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.