Real Time and Highly Sensitive Sub‐Wavelength 2D Hybrid Perovskite Photodetectors

Abstract Layered (2D) perovskites are an emerging attractive 2D system with enhanced stability to ambient conditions as opposed to their highly unstable three dimensional bulk counterpart. Their uniquely tuneable optical and electrical properties are underpinning a surge of interest in 2D‐photovoltaics. So far, the development of nano‐scale integrated opto‐electronic 2D perovskite devices remains nearly unexplored since they have generally been found to be incompatible with standard top‐down semiconductor nano‐fabrication technologies. Here, following the synthesis of solvent‐stable 2D‐fluorinated phenethylammonium lead iodide perovskite (F‐PEA)₂PbI₄ (F‐PEAI), planar photodetectors entirely fabricated in atmosphere is demonstrated, exhibiting figures of merit rivalling those of commercial silicon photodiodes. A record large room temperature detectivity (>5 × 10¹⁷ Jones), a fast time photoresponse (rise time 1.5 ns), an extraordinarily large linear dynamic range (228 dB), as well as a photo‐responsivity of ≈ 1100 AW⁻¹ are demonstrated for devices on a range of substrates including flexible wearable media without the need for any planarization or any atomically thin dielectric, in stark contrast to other 2D semiconductors. Finally, the suitability of nano‐scale 2D F‐PEAI photodetector arrays with sub‐wavelength pixel size of just 100 nm of use for high definition imaging is demonstrated.