Layered Halide Double Perovskites: Dimensional Reduction of Cs<sub>2</sub>AgBiBr<sub>6</sub>

Connor, Bridget A.; Leppert, Linn; Smith, Matthew D.; Neaton, Jeffrey B.; Karunadasa, Hemamala I.

doi:10.1021/jacs.8b01543

Cited by 328 publications

(550 citation statements)

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“…The design strategy of dimensional reduction, or structural transformation into a lower dimensionality, has provided remarkable changes in the electronic and physical properties of materials . The well‐known example is the exfoliation of bulk MoS 2 into single monolayers, resulting in an indirect‐to‐direct band gap transformation .…”

Section: Methodsmentioning

confidence: 99%

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

Liu

Wang

Han

et al. 2020

Chemistry A European J

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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.

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Section: Methodsmentioning

confidence: 99%

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

Liu

Wang

Han

et al. 2020

Chemistry A European J

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“…This makes it difficult to assign realistic t and µ values for crystallographic stability evaluation. [178] Copyright 2018, American Chemical Society. [51,52,97,99,101] It decreases as the X anion changes from Cl − , Br − , to I − .…”

Section: Thermodynamic Stability Of Halide Double Perovskitesmentioning

confidence: 99%

Progress of Lead‐Free Halide Double Perovskites

Igbari

Wang

Liao

2019

Advanced Energy Materials

392

305

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Although impressive performance has been obtained, PSCs are still far from commercial or real-life availability due to serious issues such as toxicity [15,16] and poor stability to heat, [17] oxygen, [18] moisture, [19,20] electric field, [21] and light. [18,22] The toxic nature of hybrid organic-inorganic lead halide perovskites has been traced to the presence of Pb in its chemical composition. [15,16,[23][24][25] Pb 2+ readily dissolves in water (e.g., rain water) to form a toxic solution capable of causing serious environmental pollution, harmful to human beings and the ecosystem. Besides their sensitivity to moisture, oxygen, light, electric field, or thermal stress, an existing self-degradation pathway [26,27] is also a big issue in hybrid organic-inorganic lead halide perovskites. Mixed-halide and mixed-cation perovskites have been investigated to address these issues. [28][29][30][31][32] The group IV elements, tin (Sn) [23,[33][34][35] and germanium (Ge), [34,36] have been employed as the replacements for Pb. However, the device performance through this approach has fallen short of the Pb-based ones. For example, the PCEs reported for Sn-based perovskite solar cells are usually less than 10%. [23,[33][34][35][37][38][39][40] In addition, the easy oxidation of Sn and Ge from the +2 state to the +4 state due to their high energy 5s and 4s orbitals makes them less promising for application in stable and long-term PSCs. [41] High throughput calculations also demonstrate that these substitutions are likely to compromise the ideal optoelectronic properties of MAPbI 3 . [42,43] Furthermore, low dimensional (e.g., 2D, 1D, and 0D) perovskites have also been used to address the stability issues in PSCs. [44][45][46][47][48] Recently, a stabilized PCE of 21.7% resulting from a 2D/3D bilayer PSC was reported. [49] However, the highest certified PCE in a 2D-only planar PSC is 15.3%, [50] which is far below that of their 3D perovskite-based counterparts. It thus stimulates the interest to develop new classes of materials which can solve the issues of toxicity and stability while still maintaining the fascinating properties of lead-based perovskite materials.Recent theoretical calculations demonstrate that a halide double perovskite structure, A 2 B′B″X 6 , which could be formed through a replacement of two toxic Pb 2+ in the crystal lattice with a pair of nontoxic heterovalent (i.e., monovalent and trivalent) metal cations, is a promising alternative to realize high-performance, lead-free, and stable PSCs. [51,52] Although, spectroscopic limited maximum efficiency (SLME) calculations revealed an efficiency limit less than 8% for the most prominent member www.advancedsciencenews.com double perovskites with a vacancy ordered structure. [88] In particular, the unit cell axis of Cs 2 AgBiBr 6 is given to be ≈11.25 Å, [25] which is two times larger than that of MAPbBr 3 (≈5.92 Å). [89] Both Ag + and Bi 3+ occupy the B-site of the crystal lattice with slightly varied metal-halide bond lengths. The dissimilar bond lengths st...

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“…This is evidenced by the small electron effective mass calculated for 1 (m * e ¼0.23, Table S4). Many double perovskites have similar MMCT character in their band edges [22] and thus their band gaps depend strongly on the energy spacing between the two metals frontier orbitals.F or example,C s 2 Ag I Bi III Cl 6 [5] and Cs 2 Tl I Tl III Cl 6 [15] are isostructural with 1 and represent as ingle substitution at the Bsite, replacing either Tl 3+ with Bi 3+ or Ag + with Tl + ,r espectively. Second, alow band gap is consistent with asmall intrinsic energy difference between filled Ag 4d and vacant Tl 6s orbitals,inherited from the atomic limit ( Figure 3C).…”

Section: Angewandte Chemiementioning

confidence: 99%

Small‐Band‐Gap Halide Double Perovskites

et al. 2018

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Despite their compositional versatility, most halide double perovskites feature large band gaps. Herein, we describe a strategy for achieving small band gaps in this family of materials. The new double perovskites Cs AgTlX (X=Cl (1) and Br (2)) have direct band gaps of 2.0 and 0.95 eV, respectively, which are approximately 1 eV lower than those of analogous perovskites. To our knowledge, compound 2 displays the lowest band gap for any known halide perovskite. Unlike in A B X perovskites, the band-gap transition in A BB'X double perovskites can show substantial metal-to-metal charge-transfer character. This band-edge orbital composition is used to achieve small band gaps through the selection of energetically aligned B- and B'-site metal frontier orbitals. Calculations reveal a shallow, symmetry-forbidden region at the band edges for 1, which results in long (μs) microwave conductivity lifetimes. We further describe a facile self-doping reaction in 2 through Br loss at ambient conditions.

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Layered Halide Double Perovskites: Dimensional Reduction of Cs₂AgBiBr₆

Cited by 328 publications

References 42 publications

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

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

Progress of Lead‐Free Halide Double Perovskites

Small‐Band‐Gap Halide Double Perovskites

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Layered Halide Double Perovskites: Dimensional Reduction of Cs2AgBiBr6

Cited by 328 publications

References 42 publications

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

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

Progress of Lead‐Free Halide Double Perovskites

Small‐Band‐Gap Halide Double Perovskites

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Layered Halide Double Perovskites: Dimensional Reduction of Cs₂AgBiBr₆

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

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