Highly sensitive DUV-SWIR photodetectors by natural flavonoid-derivative isomers through a multisite chelation strategy

Achieving high crystallization and excellent charge transport in lead halide perovskite is crucial for broadband photodetectors (PDs), but remains a significant challenge. Herein, a series of natural flavonoid-derivative isomers with hydroxy and carbonyl groups are applied to modify perovskite PDs. Unlike the single-point coordination or weak van der Waals interactions commonly observed between organic molecules and perovskite, the multiple functional groups in isomers can form stable chelate ring to "lock" Pb2+, enhancing crystal quality, reducing defects density, and improving stability. Especially, quercetin (QC) modified perovskite achieves the outstanding performance stemming from the coordination of its multisite acidic hydroxyl groups, which creates an optimal stereochemical environment for chelation. Moreover, the QC treatment imparts more pronounced n-type behavior of perovskite, optimizing the energy alignment and facilitating interfacial charge extraction, thereby improving the sensitivity of PDs. Consequently, a single deep-ultraviolet-to-short-wavelength-infrared PD is fabricated by combining the QC modified perovskite with In0.53Ga0.47As, showing a detectivity of 2.71×1013 Jones and an external quantum efficiency of 189.41%. Furthermore, unencapsulated device retains 98.4% of its initial sensitivity after 50000 ON/OFF cycles. Ultimately, the PD array is constructed for high-resolution pixel-level multispectral imaging.