Cooperative B-site octahedral tilting, distortion and A-site conformational change induced phase transition of 2D Lead Halide Perovskite

2021 ◽  
Author(s):  
Muhammad Azeem ◽  
Yan Qin ◽  
Zhi-Gang Li ◽  
Wei Li
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Conformational Change ◽  
Halide Perovskite ◽  
Octahedral Tilting ◽  
A Site ◽  
Lead Halide

Hybrid organic-inorganic perovskites (HOIPs) can show diverse phase transitions which give rise to desirable properties such as ferroelectricity and piezoelectricity. Hitherto, the origin of their phase transitions is primarily due...

scholarly journals Seed Mediated Synthesis of Colloidal Halide Perovskite Nanoplatelets

2021 ◽  
Author(s):  
C. Meric Guvenc ◽  
sinan balci
Keyword(s):  
Optical Properties ◽  
Halide Salt ◽  
Seed Solution ◽  
Synthesis Route ◽  
Line Widths ◽  
Halide Perovskite ◽  
Seed Mediated ◽  
A Site ◽  
First Time ◽  
Lead Halide

<p><b>Two-dimensional lead halide perovskite nanoplatelets (2D LHP NPLs) have been emerging as one of the most promising semiconductor nanomaterials due to their narrow absorption and emission line widths, tunable bandgaps, high exciton binding energies, high defect tolerance as well as highly localized energy states. Colloidal synthesis of 2D LHP NPLs is generally performed using hot-injection or ligand assisted precipitation techniques (LARP). In the LARP method, perovskites are synthesized in polar solvents, which decrease the stability of the 2D LHP NPLs due to their weakly bonded nature. In fact, the presence of residual polar solvent in the LHP NPL colloid can cause deterioration of thickness uniformity, degradation of NPLs to parent precursors, and undesired phase transformations. Herein, for the first time, we report facile seed-mediated synthesis route of monolayer, 2-monolayers, and thicker lead halide perovskite nanoplatelets without using A site cation halide salt (AX</b><b>;</b><b> A = Cesium, methylammonium, formamidinium and, X = Cl, Br, I) and long chain alkylammonium halide salts (LX; L = oleylammonium, octylammonium, butylammonium and, X = Cl, Br, I). The seed solution has been synthesized by reacting lead (II) halide salt and coordinating ligands (oleylamine or octylamine and oleic acid) in nonpolar high boiling solvent (1-octadecene). The seed mediated synthesis has been carried out in hexane by reacting seed solution with A-site cation precursors (Cs-oleate, FA-oleate, or diluted MA solution in hexane) under ambient conditions. More importantly, the seed mediated growth of NPLs has been tracked for the first time by performing in-situ optical measurements. Furthermore, the optical properties and morphologies of the seeds have been extensively studied. We find that our facile synthesis route provides highly stable, monodisperse NPLs with narrow absorption, and photoluminescence line widths (68-201 meV), and high PLQY (37.6-1.66% for 2ML NPLs). Furthermore, anion exchange reactions have been performed by mixing pre-synthesized LHP NPLs with counter halide seeds. The optical properties of NPLs have been affectively tuned by postsynthetic chemical reactions without changing the thickness of the NPLs. We anticipate that our new synthetic route provides further understanding of growth dynamics of LHP NPLs.</b></p>

scholarly journals Mixed-Solvent Polarity-Assisted Phase Transition of Cesium Lead Halide Perovskite Nanocrystals with Improved Stability at Room Temperature

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1537 ◽  
Author(s):  
Rui Yun ◽  
Li Luo ◽  
Jingqi He ◽  
Jiaxi Wang ◽  
Xiaofen Li ◽  
...  
Keyword(s):  
Phase Transition ◽  
Surface Defects ◽  
Defect Density ◽  
Solvent Polarity ◽  
Electrical Performance ◽  
Ammonium Bromide ◽  
Perovskite Nanocrystals ◽  
Improved Stability ◽  
Halide Perovskite ◽  
Lead Halide

Cesium lead halide perovskite nanocrystals (NCs) have attracted enormous interest in light-emitting diode, photodetector and low-threshold lasing application in terms of their unique optical and electrical performance. However, little attention has been paid to other structures associated with CsPbBr3, such as CsPb2Br5. Herein, we realize a facile method to prepare dual-phase NCs with improved stability against polar solvents by replacing conventional oleylamine with cetyltrimethyl ammonium bromide (CTAB) in the reprecipitation process. The growth of NCs can be regulated with different ratios of toluene and ethanol depending on solvent polarity, which not only obtains NCs with different sizes and morphologies, but also controls phase transition between orthorhombic CsPbBr3 and tetragonal CsPb2Br5. The photoluminescence (PL) and defect density calculated exhibit considerable solvent polarity dependence, which is ascribed to solvent polarity affecting the ability of CTAB to passivate surface defects and improve stoichiometry in the system. This new synthetic method of perovskite material will be helpful for further studies in the field of lighting and detectors.

Doping Induces Structural Phase Transitions in All-Inorganic Lead Halide Perovskite Nanocrystals

2020 ◽  
Vol 2 (4) ◽  
pp. 367-375 ◽  
Author(s):  
Ju-Ping Ma ◽  
Jia-Kai Chen ◽  
Jun Yin ◽  
Bin-Bin Zhang ◽  
Qing Zhao ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Perovskite Nanocrystals ◽  
Inorganic Lead ◽  
Halide Perovskite ◽  
Lead Halide

Electrochemically Quantifying the Phase Transition of Cesium Lead Halide Perovskite Quantum Dots in Purification

2021 ◽  
pp. 11042-11049
Author(s):  
Xiaolin Zhang ◽  
Kairan Huang ◽  
Nanlin Zhang ◽  
Zufu Luo ◽  
Chengqun Wang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Quantum Dots ◽  
Perovskite Quantum Dots ◽  
Halide Perovskite ◽  
Lead Halide

scholarly journals Role of lattice distortion and A site cation in the phase transitions of methylammonium lead halide perovskites

2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Jonathon R. Harwell ◽  
Julia L. Payne ◽  
Muhammad T. Sajjad ◽  
Frank J. L. Heutz ◽  
Daniel M. Dawson ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Lattice Distortion ◽  
Halide Perovskites ◽  
A Site ◽  
Lead Halide

scholarly journals A-site order in rhombohedral perovskite-like oxides La2−xSrxCoTiO6(0.6 ≤x≤ 1.0)

2016 ◽  
Vol 49 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Alejandro Gómez-Pérez ◽  
Clemens Ritter ◽  
Khalid Boulahya ◽  
Alvaro Muñoz-Noval ◽  
Flaviano García-Alvarado ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Internal Pressure ◽  
Room Temperature ◽  
Temperature Structure ◽  
Cell Parameters ◽  
First Order ◽  
Cubic Structure ◽  
Octahedral Tilting ◽  
A Site ◽  
Rhombohedral Symmetry

The evolution of the room-temperature structure of the oxide series La2−xSrxCoTiO6(0.6 ≤x≤ 1.0) was studied as a function of the Sr content using different diffraction techniques and applying the symmetry-adapted modes formalism (AMPLIMODES). The title compounds adopt perovskite-like structures of rhombohedral symmetry with an octahedral tilting scheme (a−a−a−) with either space group R\overline 3c orR32. The latter symmetry is observed in those cases (forx≃ 0.6) where additional rock-salt-like ordering of La and Sr is produced in the perovskiteAsites. Two composition-driven phase transitions are observed in the whole series La2−xSrxCoTiO6(0.0 ≤x≤ 1.0). Using the concept of internal pressure, the effect of doping with Sr on the structure can be properly discussed. Both phase transitions seem to be of first order since they can be associated with discontinuities either in the entropy or in the structure. The first transition (P21/n→Pnma) occurs as theBcations become totally disordered. Along the whole compositional range the modes responsible for the out-of-phase tilting ofBO6octahedra remain active, but those associated with the in-phase octahedral tilting vanish forx≥ 0.6, this being associated with the second transition (Pnma→ R\overline 3c). Finally, forx= 1.0 the three pseudo-cubic cell parameters become very similar, pointing to a transition to a cubic structure which could be obtained by applying pressure or raising the temperature.

Understanding the temperature-dependent charge transport, structural variation and photoluminescent properties in methylammonium lead halide perovskite single crystals

2018 ◽  
Vol 6 (24) ◽  
pp. 6556-6564 ◽  
Author(s):  
Jiyu Zhou ◽  
Na Lei ◽  
Huiqiong Zhou ◽  
Yuan Zhang ◽  
Zhiyong Tang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Charge Transport ◽  
Single Crystals ◽  
Structural Variation ◽  
Orthorhombic Phase ◽  
Temperature Dependent ◽  
Halide Perovskite ◽  
Lead Halide

Temperature dependent XRD illustrates a tetragonal to orthorhombic phase transition around 150 K in methylammonium lead halide perovskite single crystals.

scholarly journals Seed Mediated Synthesis of Colloidal Halide Perovskite Nanoplatelets

2021 ◽  
Author(s):  
C. Meric Guvenc ◽  
sinan balci
Keyword(s):  
Optical Properties ◽  
Halide Salt ◽  
Seed Solution ◽  
Synthesis Route ◽  
Line Widths ◽  
Halide Perovskite ◽  
Seed Mediated ◽  
A Site ◽  
First Time ◽  
Lead Halide

<p><b>Two-dimensional lead halide perovskite nanoplatelets (2D LHP NPLs) have been emerging as one of the most promising semiconductor nanomaterials due to their narrow absorption and emission line widths, tunable bandgaps, high exciton binding energies, high defect tolerance as well as highly localized energy states. Colloidal synthesis of 2D LHP NPLs is generally performed using hot-injection or ligand assisted precipitation techniques (LARP). In the LARP method, perovskites are synthesized in polar solvents, which decrease the stability of the 2D LHP NPLs due to their weakly bonded nature. In fact, the presence of residual polar solvent in the LHP NPL colloid can cause deterioration of thickness uniformity, degradation of NPLs to parent precursors, and undesired phase transformations. Herein, for the first time, we report facile seed-mediated synthesis route of monolayer, 2-monolayers, and thicker lead halide perovskite nanoplatelets without using A site cation halide salt (AX</b><b>;</b><b> A = Cesium, methylammonium, formamidinium and, X = Cl, Br, I) and long chain alkylammonium halide salts (LX; L = oleylammonium, octylammonium, butylammonium and, X = Cl, Br, I). The seed solution has been synthesized by reacting lead (II) halide salt and coordinating ligands (oleylamine or octylamine and oleic acid) in nonpolar high boiling solvent (1-octadecene). The seed mediated synthesis has been carried out in hexane by reacting seed solution with A-site cation precursors (Cs-oleate, FA-oleate, or diluted MA solution in hexane) under ambient conditions. More importantly, the seed mediated growth of NPLs has been tracked for the first time by performing in-situ optical measurements. Furthermore, the optical properties and morphologies of the seeds have been extensively studied. We find that our facile synthesis route provides highly stable, monodisperse NPLs with narrow absorption, and photoluminescence line widths (68-201 meV), and high PLQY (37.6-1.66% for 2ML NPLs). Furthermore, anion exchange reactions have been performed by mixing pre-synthesized LHP NPLs with counter halide seeds. The optical properties of NPLs have been affectively tuned by postsynthetic chemical reactions without changing the thickness of the NPLs. We anticipate that our new synthetic route provides further understanding of growth dynamics of LHP NPLs.</b></p>

scholarly journals Defect-Triggered Phase Transition in Cesium Lead Halide Perovskite Nanocrystals

2019 ◽  
Vol 1 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Ju-Ping Ma ◽  
Jun Yin ◽  
Ya-Meng Chen ◽  
Qing Zhao ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Phase Transition ◽  
Perovskite Nanocrystals ◽  
Halide Perovskite ◽  
Lead Halide

scholarly journals Tailoring phase transition temperatures in perovskites via A-site vacancy generation

2017 ◽  
Vol 46 (22) ◽  
pp. 7253-7260 ◽  
Author(s):  
Thomas A. Whittle ◽  
William R. Brant ◽  
James R. Hester ◽  
Qinfen Gu ◽  
Siegbert Schmid
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperatures ◽  
Temperature Dependent ◽  
Vacancy Generation ◽  
Phase Transition Temperatures ◽  
A Site ◽  
Site Vacancy

Tetragonal strain squared values for each composition across the Sr0.8Ti0.6−xZrxNb0.4O3, 0 ≤ x ≤ 0.6, series were used to accurately determine temperature dependent phase transitions (x = 0.6 is shown).

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