Ultrasensitive Near‐Infrared Circularly Polarized Light Detection Using 3D Perovskite Embedded with Chiral Plasmonic Nanoparticles

Chiral organic ligand‐incorporated low‐dimensional metal‐halide perovskites have received increasing attention for next‐generation photodetectors because of the direct detection capability of circularly polarized light (CPL), which overcomes the requirement for subsidiary optical components in conventional CPL photodetectors. However, most chiral perovskites have been based on low‐dimensional structures that confine chiroptical responses to the ultraviolet (UV) or short‐wavelength visible region and limit photocurrent due to their wide bandgap and poor charge transport. Here, chiroptical properties of 3D Cs(0.05)FA(0.5)MA(0.45)Pb(0.5)Sn(0.5)I(3) polycrystalline films are achieved by incorporating chiral plasmonic gold nanoparticles (AuNPs) into the mixed Pb—Sn perovskite, without sacrificing its original optoelectronic properties. CPL detectors fabricated using chiral AuNP‐embedded perovskite films can operate without external power input; they exhibit remarkable chirality in the near‐infrared (NIR) region with a high anisotropy factor of responsivity (g (res)) of 0.55, via giant plasmon resonance shift of chiral plasmonic AuNPs. In addition, a CPL detector array fabricated on a plastic substrate demonstrates highly sensitive self‐powered NIR detection with superior flexibility and durability.