Ultrahigh-performance photodetectors based on low-dimensional CsAgBiBr/CdS heterojunction.

Lead-free double perovskite CsAgBiBr has garnered increasing attention in photoelectric applications owing to its good stability and excellent photoelectric properties. However, the poor carrier transport in CsAgBiBr thin films constraints their further application in photodetection. To overcome this issue, we have developed an innovative low-dimensional CsAgBiBr/CdS heterojunction photodetector with substantially improved performance. The device achieved a high responsivity of 6.66 × 10 A/W, an outstanding specific detectivity of 2.10 × 10 Jones, and an impressive external quantum efficiency of 1.88 × 10 %. Additionally, the on/off current ratio of the heterojunction device reached an impressive 6.18 × 10. These key parameters are significantly better than those of most previously reported CsAgBiBr-based photodetectors. Furthermore, scanning photocurrent mapping and band arrangement analysis were performed to elucidate the mechanism of photocurrent generation and transport in the low-dimensional CsAgBiBr/CdS heterojunction photodetectors. This study highlights the outstanding performance of CsAgBiBr/CdS heterojunction and provides a simple and effective strategy for developing high-performance CsAgBiBr-based photodetectors.