Achieving High Performance in Lead-Free Double Perovskite Photodetectors through Mg-Doped Hole Transport Layers

A high-performance photodetector based on lead-free double perovskite and a Mg-doped hole transport layer has been developed. In this study, we demonstrate the successful incorporation of Mg into the hole transport layer of the double perovskite photodetector, leading to an enhanced device performance. Mg doping in NiO x increases the Ni vacancy concentration in NiO x, thereby enhancing charge transport properties and reducing recombination rates, ultimately leading to significant improvements in device responsivity and detectivity. The champion device demonstrates state-of-the-art performance metrics, including a specific detectivity of 4.7 × 10 12 Jones, an ultralow dark current density of 5.5 × 10 –9 A·cm –2, and a fast transient photocurrent response speed of 382 μs (rise)/120 μs (fall). Furthermore, it achieves an impressive linear dynamic range of 101 dB, outperforming most of its reported counterparts in the field. This work presents a promising approach for the development of environmentally friendly and high-performance photodetectors.