Oriented Perovskite Growth Regulation Enables Sensitive Broadband Detection and Imaging of Polarized Photons Covering 300–1050 nm

Abstract

Photodetectors selective to the polarization empower breakthroughs in sensing technology for target identification. However, the realization of polarization-sensitive photodetectors based on intrinsically anisotropic crystal structure or extrinsically anisotropic device pattern requires complicated epitaxy and etching processes, which limit scalable production and application. Here, solution-processed PEA2 MA4 (Sn0.5 Pb0.5 )5 I16 (PEA= phenylethylammonium, MA= methylammonium) polycrystalline film is probed as photoactive layer toward sensing polarized photon from 300 to 1050nm. The growth of the PEA2 MA4 (Sn0.5 Pb0.5 )5 I16 crystal occurs in confined crystallographic orientation of the (202) facet upon the assistance of NH4 SCN and NH4 Cl, enhancing anisotropic photoelectric properties. Therefore, the photodetector achieves a polarization ratio of 0.41 and dichroism ratio (Imax /Imin ) of 2.4 at 900nm. At 520nm, the Imax /Imin even surpasses the one of the perovskite crystalline films, 1.8 and ≈1.2, respectively. It is worth noting that the superior figure-of-merits possess a response width of 900kHz, Ion /Ioff ratio of ≈3 × 108 , linear dynamic range from 0.15 nW to 12mW, noise current of 8.28 × 10-13 A × Hz-0.5 , and specific detectivity of 1.53 × 1012 Jones, which demonstrate high resolution and high speed for weak signal sensing and imaging. The proof of concept in polarized imaging confirms that the polarization-sensitive photodetector meets the requirements for practical application in target recognition.