Ultra-broadband Photodetectors Based on Formamidinium Lead Iodide Quantum Dots

• Synthesis and comprehensive characterization of highly stable and emissive FAPbI 3 quantum dots, exhibiting a broad absorption spectrum from 300 to 900 nm and a high photoluminescence quantum yield, laying the foundation for ultra-broadband photodetection. • Systematic optimization of the device structure, leveraging PCBM as the electron transport layer and TAPC as the hole transport layer, to achieve optimal energy level alignment and charge transport efficiency, resulting in impressive external quantum efficiencies of up to 59.56 % at 750 nm. • Demonstration of exceptional device performance metrics, including a high specific detectivity of 2.63 x 10 11 Jones, fast temporal response with rise/fall times of 30.58/31.26 μs, and a wide linear dynamic range of 61.5 dB under 780 nm illumination, enabled by the low dark current densities facilitated by the judicious material and thickness selection. • Comprehensive characterization and analysis of the device performance, highlighting the potential of FAPbI 3 quantum dots for high-sensitivity, high-speed, and broadband NIR photodetection applications, opening new avenues for scientific exploration and technological innovation. Near-infrared photodetectors were fabricated by incorporating formamidinium lead iodide (FAPbI 3 ) quantum dots (QDs) as the light-harvesting layer. Through systematic optimization of the device architecture, high device performance was achieved by utilizing PCBM as the electron transport material and a 50 nm-thick TAPC film as the hole transport layer. The energy level alignment between PCBM and the FAPbI 3 QDs enabled efficient exciton dissociation and hole blocking, while the optimized TAPC thickness decrease current leakage pathways. The resulting photodetectors exhibited an impressive external quantum efficiency of 59.56 % at 750 nm, along with a high specific detectivity of 2.63 x 10 11 Jones. A broadband photoresponse from 300–900 nm was observed, as well as a fast temporal response with 30.58/31.26 μs rise/fall times. A substantial linear dynamic range of 61.5 dB was achieved under 780 nm illumination. Furthermore, the low dark current densities facilitated by the judiciously selected materials and thicknesses contributed to the excellent overall device performance. The device performance of the PCBM/FAPbI 3 QDs/TAPC system demonstrate its promising potential for near-infrared optoelectronic applications requiring high sensitivity, speed, and broad spectral response, opening up opportunities for further advances in photodetection as well as other relevant device technologies.