Multinoncentrosymmetric Two-Dimensional Trilayered Lead Bromide Perovskites with Methylhydrazinium Cations: Lattice Dynamics, Phase Transitions, Dielectric Response, and Optical Properties

Chemistry of Materials, Journal Year: 2024, Volume and Issue: 36(17), P. 8286 - 8299

Published: Aug. 20, 2024

Multilayered Ruddlesden–Popper hybrid lead halide perovskites are an emerging class of soft that exhibit exceptional linear and nonlinear optical properties as well ferroelectric antiferroelectric characteristics. Due to these features, they show immense potential in energy conversion, storage, light emission, photodetector technologies. The structural phase transitions lattice dynamics organic cations play key roles the performance perovskites. Herein, we report studies two bromide – BA2MHy2Pb3Br10 iBA2MHy2Pb3Br10 (BA, butylammonium; iBA, iso-butylammonium; MHy, methylhydrazinium). Our multitechnique approach [X-ray diffraction, thermal, dielectric, second harmonic generation (SHG), Raman scattering, infrared (IR) spectroscopy] BA analogue undergoes distinct at 372 301 K, while iBA exhibits a more complex sequence four 364, 262, 223, 189 K. It turns out all phases noncentrosymmetric, except for high-temperature ones. By employing IR spectroscopy, reveal transition both compounds is triggered by ordering MHy+ cage cations, slowing down interlayer BA+ iBA+ cation plays major role mechanism lowest-temperature transitions. As such, this study marks first instance where spectroscopic techniques have been successfully employed monitor independently within also demonstrates recently reported excellent polarized photodetection iBAMHy2Pb3Br10 primarily related polar order cations. Dielectric presence dipolar relaxation process sample below 230 associated with motions Both emit luminescence under one- two-photon excitation, yet profiles differ due different populations excitons being excited through (365 nm) (800 pathways. color changes from purplish-blue 365 nm excitation blue 800 excitation. Overall, our findings comprising may rich polymorphism, multinoncentrosymmetry, multiple responses (one- emissions, SHG), which affected type (size shape)

Language: Английский

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Two-Dimensional Lead Iodide Perovskites with Extremely Reduced Dielectric Confinement: Embedded Self-Erasing Second-Harmonic Generation Switching, Thermochromism, and Photoluminescence

Chemistry of Materials, Journal Year: 2024, Volume and Issue: 36(21), P. 10758 - 10772

Published: Oct. 16, 2024

Ethanolammonium lead iodide (EOA2PbI4) and propanolammonium (AP2PbI4) are two-dimensional hybrid organic–inorganic perovskites with reduced dielectric confinement exciton binding energy. These compounds exist in three polymorphic forms, two of which metastable, each distinct constants, nonlinear optical (NLO) properties, photoluminescence characteristics. The initial red phases I isostructural, displaying monoclinic P21/c symmetry narrow-line green PL, stable up to approximately 369 K for EOA2PbI4 319 AP2PbI4. Beyond these temperatures, they undergo a reconstructive first-order phase transition high-temperature II, characterized by unlocked organic cation motion, as indicated Raman data. This results color change orange (yellow) due blue shift the band gap excitonic absorption, more pronounced II is prone supercooling metastable regime, where it either reverts or transforms new low-temperature III ordered cations slightly distorted inorganic substructure. In III, single broad peak, large Stokes shift, electron–phonon coupling, particularly AP2PbI4 (>1 eV), indicating significant substructure deformation. Phase lacks second-harmonic generation (SHG) activity, while SHG response observed EOA2PbI4. metastability acentric supercooled centric harnessed introduce type NLO functionality, namely, embedded self-erasing switching. "embedded" scheme requires thermodynamically unstable crystal phases, one noncentrosymmetric, necessitates thermal activation, such annealing followed cooling. unconventional route triggering responses, along spontaneous reversion centrosymmetric phase, enables switching between SHG-on SHG-off states.

Language: Английский

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Overview of the Recent Findings in the Perovskite-Type Structures Used for Solar Cells and Hydrogen Storage

Energies, Journal Year: 2024, Volume and Issue: 17(18), P. 4755 - 4755

Published: Sept. 23, 2024

Perovskite-type structures have unique crystal architecture and chemical composition, which make them highly attractive for the design of solar cells. For instance, perovskite-based cells been shown to perform better than silicon cells, capable adsorbing a wide range light wavelengths, they can be relatively easily manufactured at low cost. Importantly, also adsorb significant amount hydrogen atoms into their own structure; therefore, perovskite holds promise in solid-state storage hydrogen. It is widely expected by scientific community that controlled adsorption/desorption into/from help overcome main issues such as volumetric density safety concerns (i.e., embrittlement affects strongly mechanical properties metals and, such, or transport gaseous vessels is, especially large vessel volumes, challenging). The purpose this review provide an updated overview recent results studies focusing on materials used both applications. Particular attention given (i) preparation achievable efficiency stability (ii) structural, thermodynamic, hydrides oxides. We show not only reach above current Si-based but also, due good reasonable price, preferable Then, future trends directions research application are highlighted.

Language: Английский

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Organic cations in halide perovskite solid solutions: exploring beyond size effects

Published: June 24, 2024

Halide perovskites are a class of materials consolidated optoelectronic and electrochemical applications, reaching efficiencies compared to established in respective fields. In this scenario, the design understanding composition-structure-property relations is imperative. solid solutions containing mixed cations, some direct between sizes substituents properties generally observed. However, several cases, these not observed, implying that other characteristics cations play major role. Despite its importance, has been comprehensively deepened. To address issue, we synthesized characterized structure, electrical behavior, stability methylammonium lead iodide-based with equal amounts guanidinium, ethylammonium, acetamidinium. These three large organic have essentially but remarkably different characteristics, such as number N-H bonds, intrinsic dipole moment, order C-N bonds. Herein, show dramatically effects over important fundamental applied resulting perovskites, including orthorhombic-to-tetragonal tetragonal-to-cubic phase transitions, microstructural development, ionic conductivity, I-V hysteresis, electronic carrier mobility, against light-induced degradation. correlated substituent help pave way for better rational chemical halide perovskites.

Language: Английский

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Phonon Properties and Lattice Dynamics of Two- and Tri-Layered Lead Iodide Perovskites Comprising Butylammonium and Methylammonium Cations—Temperature-Dependent Raman Studies

Materials, Journal Year: 2024, Volume and Issue: 17(11), P. 2503 - 2503

Published: May 22, 2024

Hybrid lead iodide perovskites are promising photovoltaic and light-emitting materials. Extant literature data on the key optoelectronic luminescent properties of hybrid indicate that these affected by electron–phonon coupling, dynamics organic cations, degree lattice distortion. We report temperature-dependent Raman studies BA2MAPb2I7 BA2MA2Pb3I10 (BA = butylammonium; MA methylammonium), which undergo two structural phase transitions. obtained in broad temperature (360–80 K) wavenumber (1800–10 cm−1) ranges show ordering BA+ cations triggers higher transition, whereas freezing MA+ occurs below 200 K, leading to onset low-temperature transition. This is associated with significant deformation inorganic sublattice, as evidenced changes observed mode region. Our results show, therefore, spectroscopy a very valuable tool for monitoring separate different perovskites, comprising “perovskitizer” interlayer cations.

Language: Английский

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