Multilayered 2D Cesium‐Based Hybrid Perovskite with Strong Polarization Sensitivity: Dimensional Reduction of CsPbBr₃

Abstract

3D perovskite CsPbBr3 has recently taken a blooming position for optoelectronic applications. However, due to the lack of natural anisotropy of optical attributes, it is a great challenge to fulfil polarization‐sensitive photodetection. Here, for the first time, we exploited dimensionality reduction of CsPbBr3 to tailor a 2D‐multilayered hybrid perovskite, (TRA)2CsPb2Br7 (1, in which TRA is (carboxy)cyclohexylmethylammonium), serving as a potential polarized‐light detecting candidate. Its unique quantum‐confined 2D structure results in intrinsic anisotropy of electrical conductivity, optical absorbance, and polarization‐dependent responses. Particularly, it exhibits remarkable dichroism with the photocurrent ratio (Ipc/Ipa) of ≈2.1, being much higher than that of the isotropic CsPbBr3 crystal and reported CH3NH3PbI3 nanowire (≈1.3), which reveals its great potentials for polarization‐sensitive photodetection. Further, crystal‐based detectors of 1 show fascinating responses to the polarized light, including high detectivity (>1010 Jones), fast responding time (≈300 μs), and sizeable on/off current ratios (>104). To our best knowledge, this is the first study on 2D Cs‐based hybrid perovskite exhibiting strong polarization‐sensitivity. The work highlights an effective pathway to explore new polarization sensitive candidates for hybrid perovskites and promotes their future electronic applications.

Two‐Dimensional Guanidine‐Based Hybrid Perovskites with Strong Dichroism for Multiwavelength Polarization‐Sensitive Detection

“…The dichroic ratios ( I max / I min ) are calculated to be 2.2, 1.29 and 1.23 for 520, 405 and 637 nm incident polarized‐light. For so large of these values, as far as we know, can be compared with those of some other 2D materials, such as PdSe 2 (∼2.2 and 1.8 for 369 and 532 nm, respectively), GeSe (∼2.16) and (TRA) 2 CsPb 2 Br 7 (∼2.1) (Figure S7 and Table S4, Supporting Information) [6,36,46] . Finally, the dichroic ratio of above‐mentioned three wavelengths of 10 crystal‐based devices was measured, the test results demonstrate that our devices hold large dichroic ratios (Figure 5d).…”

“…For so large of these values, as far as we know, can be compared with those of some other 2D materials, such as PdSe 2 (~2.2 and 1.8 for 369 and 532 nm, respectively), GeSe (~2.16) and (TRA) 2 CsPb 2 Br 7 (~2.1) (Figure S7 and Table S4, Supporting Information). [6,36,46] Finally, the dichroic ratio of above-mentioned three wavelengths of 10 crystal-based devices was measured, the test results demonstrate that our devices hold large dichroic ratios (Figure 5d). All these attributes make (BA) 2 (GA)Pb 2 I 7 as an inherent linear dichroic component for potential high-performance multiwavelength polarizationsensitive detection.…”

“…Therefore, 2D hybrid perovskites with intrinsic linear dichroism show unique preponderance of polarized‐light detection. Recently, substantial 2D perovskites containing small‐size cations as the ′′perovskitizer′′, such as (BA) 2 (MA)Pb 2 Br 7 and (TRA) 2 CsPb 2 Br 7 (MA is methylamine, CH 3 NH 3 + ; TRA is (carboxy)cyclohexymethylammonium, HOOC(C 6 H 10 )CH 2 NH 3 + ), have been reported as the promising polarized‐light detectors based on single crystals [36,37] . Owing to the strict restriction of Tolerance Factor concept, it is quite challenging to accommodate organic cations with larger ionic radii into the perovskite cavities.…”

“…Recently, substantial 2D perovskites containing small-size cations as the ''perovskitizer'', such as (BA) 2 (MA)Pb 2 Br 7 and (TRA) 2 CsPb 2 Br 7 (MA is methylamine, CH 3 NH 3 + ; TRA is (carboxy)cyclohexymethylammonium, HOOC (C 6 H 10 )CH 2 NH 3 + ), have been reported as the promising polarized-light detectors based on single crystals. [36,37] Owing to the strict restriction of Tolerance Factor concept, it is quite challenging to accommodate organic cations with larger ionic radii into the perovskite cavities. Recently, a few 2D guanidine-based members, with guanidium (C(NH 2 ) 3 + , GA + ,~278 pm) cation confined in the perovskite cavities, were synthesized to achieve excellent semiconducting attributes.…”

Pillared cobalt metal–organic frameworks act as chromatic polarizers

“…1 This phenomenon is observed in materials that, due to their crystalline or partially ordered structure, show an overall alignment of the transition dipole moments or of nanostructured features on substrates. [2][3][4] This results in different degrees of light absorption depending on the relative orientation of the polarization direction of light. 2 For this reason, linear dichroic spectroscopy is often used to determine the structural orientation of molecules in matter.…”