Vertically Stacked Au/PbS/CsPbCl₃ Phototransistors for Plasmon-Enhanced High-Performance Broadband Photodetection

All inorganic perovskites have been regarded as attractive optoelectronic materials due to their tunable properties, good stability, and low-temperature processing techniques. However, the relatively low responsivity and narrow response range still hinder their potential for optoelectronic applications. In this work, vertically stacked Au/PbS/CsPbCl3 phototransistors were fabricated by a low-temperature solution method. The phototransistors achieved a wide spectral photodetection of 300–1100 nm. The phototransistors had an effective electron mobility of 654.75 cm2/V s without light illumination. Under 532 nm incident light, due to the enhancement of plasmonic Au nanoparticles, the phototransistors demonstrated a remarkable responsivity of 3892 A/W, a high detectivity of 3.29 × 1013 Jones, as well as an ultrahigh external quantum efficiency of 106%. In addition, the phototransistors also exhibited excellent stability in air. The results demonstrate that a vertically stacked Au/PbS/CsPbCl3 architecture is a promising candidate for broadband photodetection.