Perovskite Quantum Dot‐Ta₂NiSe₅ Mixed‐Dimensional Van Der Waals Heterostructures for High‐Performance Near‐Infrared Photodetection

Abstract 2D materials and their van der Waals heterostructures are of great fundamental interest and have potential applications in emerging electronics devices. However, atomically thin photodetector applications have suffered from performance limitations because of low optical absorption. Here, a near‐infrared photodetector based on methylammonium lead halide perovskite quantum dots (MQDs), combined with Ta₂NiSe₅ van der Waals heterostructures, is fabricated to take advantage of their energy band alignment. An ultrasensitive photoresponse with a detectivity of 6.0 × 10¹² Jones for 800 nm illumination is demonstrated. Furthermore, the field‐effect mobility and responsivity are enhanced by factors of 2 and 7.4, respectively, by interfacing Ta₂NiSe₅ and the MQDs. These results indicate that the optoelectrical properties of 2D ternary Ta₂NiSe₅ can be significantly optimized via hybridization with MQDs and can accelerate the evolution of MQD‐van der Waals heterostructure‐based devices.