Quasi-2D-Perovskite-Based Broadband Photodetector with a High <i>I</i>_on/<i>I</i>_off Ratio through Interface Engineering

A photodetector that can perceive light across a wide spectral range is crucial for various technological applications in imaging, sensing, and communication. However, the conventional silicon-based photodetector faces the challenge of absorption deficiency in the visible and ultraviolet regions, while the perovskite-based photodetector exhibits a weak response to near-infrared wavelengths. In this work, a broadband photodiode based on a silicon/quasi-two-dimensional perovskite structure was presented, which leverages the strengths of both materials to compensate for their respective deficiencies. Moreover, the introduction of the organic small-molecule material, phthalocyanine-based compound aluminum phthalocyanine chloride (AlClPc), as an interface modification layer effectively resolves the problem of high dark current in vertical devices, significantly reducing devices power consumption and enhancing the Ion/Ioff ratio. The results show that the responsivity reaches up to 23.72 A/W, and the detectivity is 2.1 × 1010 cm Hz1/2 W1–. Furthermore, the introduction of the interface layer increases the diode’s switching ratio from 27.55 to 2.35 × 102, achieving an order-of-magnitude improvement. Overall, this study demonstrates that the interface layer can effectively reduce dark current with a minimal impact on photocurrent attenuation. Furthermore, the integration of organic and inorganic structures, along with a modification layer, can be an optimal approach to promote the performance of the photodetectors, achieving a broadband, high-responsivity, and high Ion/Ioff ratio.