Great Amplification of Circular Polarization Sensitivity via Heterostructure Engineering of a Chiral Two-Dimensional Hybrid Perovskite Crystal with a Three-Dimensional MAPbI₃ Crystal

Abstract

Chiral hybrid perovskites have brought an unprecedented opportunity for circularly polarized light (CPL) detection. However, the circular polarization sensitivity of such a detector remains extremely low because of the high exciton recombination rate in those single-phase hybrid perovskites. Here, a heterostructure construction strategy is proposed to reduce the electron–hole recombination rate in a chiral hybrid perovskite and achieve CPL detectors with greatly amplified circular polarization sensitivity. A heterostructure crystal, namely, [( R )-MPA] 2 MAPb 2 I 7 /MAPbI 3 (( R )-MPA = ( R )-methylphenethylamine, MA = methylammonium), has been successfully created by integrating a chiral two-dimensional (2D) perovskite with its three-dimensional counterpart via solution-processed heteroepitaxy. Strikingly, the sharp interface of the as-grown heterostructure crystal facilitates the formation of a built-in electric field, enabling the combined concepts of charge transfer and chirality transfer, which effectively reduces the recombination probability for photogenerated carriers while retaining chiroptical activity of chiral 2D perovskite. Thereby, the resultant CPL detector exhibits significantly amplified circular polarization sensitivity at zero bias with an impressive anisotropy factor up to 0.67, which is about six times higher than that of the single-phase [( R )-MPA] 2 MAPb 2 I 7 (0.1). As a proof-of-concept, the strategy we presented here enables a novel path to modulate circular polarization sensitivity and will be helpful to design chiral hybrid perovskites for advanced chiroptical devices.

In Situ Epitaxial Growth of Centimeter-Sized Lead-Free (BA)2CsAgBiBr7/Cs2AgBiBr6 Heterocrystals for Self-Driven X-ray Detection

“…It is surprising that a compositional-gradient halide perovskite heterocrystal can be created via a low-temperature solution-processed method, which is probably due to the inherently soft crystal lattice of halide perovskites that enables greater tolerance to the lattice mismatch, making them promising for semiconductor integration. ,− The advances in heterocrystal fabrication thus offer new insights into designing halide perovskite SCs with an enhanced light–matter interaction for direct X-ray detection. For example, a cascade MAPbX 3 (X = Cl, Br, I) heterocrystal with a thickness of 7.55 mm was recently presented by Lei et al The resulting X-ray photodiodes achieved an improved sensitivity as high as 1580 μC Gy –1 cm –2 .…”

Chiral Ligand-Induced Structural Transformation of Low-Dimensional Hybrid Perovskite for Circularly Polarized Photodetection

“…Using these equations mentioned above, the maximum D * reached about 3.8 × 10 11 Jones with a light power intensity of 0.035 mW cm –2 . Table lists the corresponding comparison performance of CPL photodetectors based on chiral perovskites. ,,,,− Compared with previously reported CPL devices, the photodetector based on 1D ( R / S -NEA)­PbI 3 shows some superior properties such as the D * and g Iph value.…”

Anisotropic Low‐Dimensional Materials for Polarization‐Sensitive Photodetectors: From Materials to Devices

“…In 2021, a chiral 2D hybrid perovskite/3D MAPbI 3 crystal heterostructure has been constructed for highly circular polarization-sensitive photodetection due to the reduction of the electron-hole recombination rate. [220] In mix-dimensional systems, the build-in field plays a great important role in collecting efficient carriers to enhance the photocurrent. The same mechanism has also been utilized in 2D homojuntions and 2D heterojunctions as introduced above.…”