Mapping structural properties of lead halide perovskites by scanning nanofocus x-ray diffraction (Conference Presentation)

2017 ◽  
Author(s):  
David G. Lidzey
Keyword(s):  
Structural Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Halide Perovskites ◽  
Lead Halide

scholarly journals Progressive Polytypism and Bandgap Tuning in Azetidinium Lead Halide Perovskites

2021 ◽  
Author(s):  
Jiyu Tian ◽  
David Cordes ◽  
Alexandra Slawin ◽  
Eli Zysman-Colman ◽  
Finlay Morrison
Keyword(s):  
Linear Variation ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vegard’S Law ◽  
The Family ◽  
Halide Perovskites ◽  
Diffraction Patterns ◽  
Bandgap Tuning ◽  
Lead Halide

<div><div><div><p>Mixed halide azetidinium lead perovskites AzPbBr<sub>3-<i>x</i></sub>X<i><sub>x</sub></i> (X = Cl or I) were obtained by mechanosynthesis. With varying halide composition from Cl- to Br- to I-; the chloride and bromide analogs both form in the hexagonal 6H polytype while the iodide adopts the 9R polytype. An intermediate 4H polytype is observed for mixed Br/I compositions. Overall the structure progresses from 6H to 4H to 9R perovskite polytype with varying halide composition. Rietveld refinement of the powder X-ray diffraction patterns revealed a linear variation in unit cell volume as a function of the average radius of the anion, which is not only observed within the solid solution of each polytype (according to Vegard’s law) but extends uniformly across all three polytypes. This is correlated with a progressive (linear) tuning of the bandgap from 3.41 to 2.00 eV. Regardless of halide, the family of azetidinium halide perovskite polytypes are highly stable, with no discernible change in properties over more than 6 months under ambient conditions</p></div></div></div>

scholarly journals Size Isn’t Everything - Compositional Variation in Hybrid Organic-Inorganic Lead Halide Perovskites: Kinetically- versus Thermodynamically-controlled Synthesis

2021 ◽  
Author(s):  
Jiyu Tian ◽  
Eli Zysman-Colman ◽  
Finlay Morrison
Keyword(s):  
Solid Solution ◽  
Solid Solutions ◽  
Compositional Variation ◽  
X Ray Diffraction ◽  
Solid Solution Formation ◽  
X Ray ◽  
H Nmr ◽  
Halide Perovskites ◽  
A Site ◽  
Lead Halide

<p>The formation and study of a partial solid solution <a></a><a>Az<sub>1-<i>x</i></sub>FA<i><sub>x</sub></i>PbBr<sub>3</sub></a>, using ‘similar’ sized cations azetidinium (Az<sup>+</sup>) and formamidinium (FA<sup>+</sup>), was explored via mechanosynthesis and precipitation synthesis. The composition and lattice parameters of samples from both syntheses were analysed by <sup>1</sup>H NMR and Rietveld refinement of the powder X-ray diffraction. A clear mismatch in the composition of the perovskite was found between the precipitated samples and the corresponding solutions. Such a mismatch was not observed for samples obtained via mechanosynthesis. The discrepancy suggests products are kinetically-controlled during precipitation, compared to thermodynamically-controlled mechanosynthesis. Furthermore, the cell volume as a function of composition in both 6H (Az-rich) and 3C (FA-rich) solid solutions suggests that FA<sup>+</sup> is actually smaller than Az<sup>+</sup>, contradicting the literature. In the 3C (Az-poor) solid solutions, the extent of Az<sub>1-<i>x</i></sub>FA<i><sub>x</sub></i>PbBr<sub>3 </sub>is unexpectedly smaller than Az<sub>1-<i>x</i></sub>MA<i><sub>x</sub></i>PbBr<sub>3</sub>, again in contradiction to the expectation based on the reported cation sizes. These results indicate that other factors, as yet unidentified, must also contribute to the solid solution formation of organic-inorganic hybrid perovskites, not simply the relative sizes of the A-site cations.</p>

scholarly journals Progressive Polytypism and Bandgap Tuning in Azetidinium Lead Halide Perovskites

2021 ◽  
Author(s):  
Jiyu Tian ◽  
David Cordes ◽  
Alexandra Slawin ◽  
Eli Zysman-Colman ◽  
Finlay Morrison
Keyword(s):  
Linear Variation ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vegard’S Law ◽  
The Family ◽  
Halide Perovskites ◽  
Diffraction Patterns ◽  
Bandgap Tuning ◽  
Lead Halide

<div><div><div><p>Mixed halide azetidinium lead perovskites AzPbBr<sub>3-<i>x</i></sub>X<i><sub>x</sub></i> (X = Cl or I) were obtained by mechanosynthesis. With varying halide composition from Cl- to Br- to I-; the chloride and bromide analogs both form in the hexagonal 6H polytype while the iodide adopts the 9R polytype. An intermediate 4H polytype is observed for mixed Br/I compositions. Overall the structure progresses from 6H to 4H to 9R perovskite polytype with varying halide composition. Rietveld refinement of the powder X-ray diffraction patterns revealed a linear variation in unit cell volume as a function of the average radius of the anion, which is not only observed within the solid solution of each polytype (according to Vegard’s law) but extends uniformly across all three polytypes. This is correlated with a progressive (linear) tuning of the bandgap from 3.41 to 2.00 eV. Regardless of halide, the family of azetidinium halide perovskite polytypes are highly stable, with no discernible change in properties over more than 6 months under ambient conditions</p></div></div></div>

scholarly journals Size Isn’t Everything - Compositional Variation in Hybrid Organic-Inorganic Lead Halide Perovskites: Kinetically- versus Thermodynamically-controlled Synthesis

2021 ◽  
Author(s):  
Jiyu Tian ◽  
Eli Zysman-Colman ◽  
Finlay Morrison
Keyword(s):  
Solid Solution ◽  
Solid Solutions ◽  
Compositional Variation ◽  
X Ray Diffraction ◽  
Solid Solution Formation ◽  
X Ray ◽  
H Nmr ◽  
Halide Perovskites ◽  
A Site ◽  
Lead Halide

<p>The formation and study of a partial solid solution <a></a><a>Az<sub>1-<i>x</i></sub>FA<i><sub>x</sub></i>PbBr<sub>3</sub></a>, using ‘similar’ sized cations azetidinium (Az<sup>+</sup>) and formamidinium (FA<sup>+</sup>), was explored via mechanosynthesis and precipitation synthesis. The composition and lattice parameters of samples from both syntheses were analysed by <sup>1</sup>H NMR and Rietveld refinement of the powder X-ray diffraction. A clear mismatch in the composition of the perovskite was found between the precipitated samples and the corresponding solutions. Such a mismatch was not observed for samples obtained via mechanosynthesis. The discrepancy suggests products are kinetically-controlled during precipitation, compared to thermodynamically-controlled mechanosynthesis. Furthermore, the cell volume as a function of composition in both 6H (Az-rich) and 3C (FA-rich) solid solutions suggests that FA<sup>+</sup> is actually smaller than Az<sup>+</sup>, contradicting the literature. In the 3C (Az-poor) solid solutions, the extent of Az<sub>1-<i>x</i></sub>FA<i><sub>x</sub></i>PbBr<sub>3 </sub>is unexpectedly smaller than Az<sub>1-<i>x</i></sub>MA<i><sub>x</sub></i>PbBr<sub>3</sub>, again in contradiction to the expectation based on the reported cation sizes. These results indicate that other factors, as yet unidentified, must also contribute to the solid solution formation of organic-inorganic hybrid perovskites, not simply the relative sizes of the A-site cations.</p>

Selective oxidation of cyclopentene to glutaraldehyde by H2O2 over Nb-SBA-15

2021 ◽  
Author(s):  
yingmeng qi ◽  
Qi Han ◽  
li wu ◽  
Jun Li
Keyword(s):  
Structural Properties ◽  
Selective Oxidation ◽  
Mesoporous Materials ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
X Ray

A series of niobium-containing mesoporous materials Nb-SBA-15 have been prepared by sonication–impregnation and hydrothermal process. The dispersion and structural properties of niobium-containing species were systematically characterized by X-ray diffraction, scanning...

Structural properties of the guest species in diacyl peroxide/urea inclusion compounds: an X-ray diffraction investigation

1990 ◽  
Vol 431 (1882) ◽  
pp. 245-269 ◽  
Keyword(s):  
Single Crystal ◽  
Structural Properties ◽  
Inclusion Compounds ◽  
X Ray Diffraction ◽  
Channel Axis ◽  
Guest Molecules ◽  
X Ray ◽  
Urea Inclusion Compounds ◽  
Diacyl Peroxide ◽  
Urea Inclusion

In this paper we report single crystal X-ray diffraction studies of urea inclusion compounds containing diacyl peroxides (dioctanoyl peroxide (OP), diundecanoyl peroxide (UP), lauroyl peroxide (LP)) as the guest component. In these inclusion compounds, the host (urea) molecules crystallize in a hexagonal structure that contains linear, parallel, non-intersecting channels (tunnels). The guest (diacyl peroxide) molecules are closely packed inside these channels with a periodic repeat distance that is incommensurate with the period of the host structure along the channel axis. Furthermore, there is pronounced inhomogeneity within the guest structure: within each single crystal, there are regions in which the guest molecules are three-dimensionally ordered, and other regions in which they are only one-dimensionally ordered (along the channel axis). Although it has not proven possible to ‘determine’ the guest structures in the conventional sense, substantial information concerning their average periodicities and their orientational relationships with respect to the host has been deduced from single crystal X-ray diffraction photographs recorded at room temperature. For OP/urea, UP/urea and LP/urea, the guest structure in the three-dimensionally ordered regions is monoclinic, and six types of domain of this monoclinic structure can be identified within each single crystal. The relative packing of diacyl peroxide molecules is the same in each domain, and the different domains are related by 60° rotation about the channel axis. For each of these inclusion compounds, the offset between the ‘heights’ of the guest molecules in adjacent channels is the same ( ca . 4.6 Å (4.6 x 10 -10 m)) within experimental error, suggesting that the relative interchannel packing of the guest molecules is controlled by a property of the diacyl peroxide group. In addition to revealing these novel structural properties, the work discussed in this paper has more general relevance concerning the measurement and interpretation of single crystal X-ray diffraction patterns that are based on more than one three-dimensionally periodic reciprocal lattice. Seven separate reciprocal lattices are required to rationalize the complete X-ray diffraction pattern from each diacyl peroxide/urea crystal studied here.

Mechanical and Structural Properties of Superhard TiAlSiN Coatings Deposited by Arc Ion Plating of Cylindrical Cathode

2014 ◽  
Vol 783-786 ◽  
pp. 1426-1431
Author(s):  
Wang Ryeol Kim ◽  
Min Chul Kwon ◽  
Jung Hoon Lee ◽  
Uoo Chang Jung ◽  
Won Sub Chung
Keyword(s):  
Structural Properties ◽  
Nitrogen Pressure ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Plating ◽  
Arc Current ◽  
Cathode Arc ◽  
Cathodic Arc ◽  
Tialsin Coating

TiAlSiN coatings were deposited on WC-Co metal by using a cathodic arc ion deposition method of cylindrical cathode. We used Ti / Al (50 / 50 at.%) arc target and silicon sputter target. The influence of the nitrogen pressure, TiAl cathode arc current, bias voltage, and deposition temperature on the mechanical and the structural properties of the films were investigated. The structural features of the films were investigation in detail using X-ray diffraction. And coatings were characterized by means of FE-SEM, nanoindentation, Scratch tester, Tribology tester, XRD and XPS. The hardness of the film reached 43 GPa at the cathode arc current of 230 A and decreased with a further increase of the arc current. And the adhesion of the film reached 34 N. The results showed that the TiAlSiN coating exhibited an excellent mechanical properties which application for tools and molds.

Crystallization of Zn-rich and P-rich amorphous Zn3P2 thin films

1988 ◽  
Vol 66 (5) ◽  
pp. 373-375 ◽  
Author(s):  
C. J. Arsenault ◽  
D. E. Brodie
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Activation Energy ◽  
Electrical Properties ◽  
Structural Properties ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Conductivity Activation Energy ◽  
X Ray

Zn-rich and P-rich amorphous Zn3P2 thin films were prepared by co-evaporation of the excess element during the normal Zn3P2 deposition. X-ray diffraction techniques were used to investigate the structural properties and the crystallization process. Agglomeration of the excess element within the as-made amorphous Zn3P2 thin film accounted for the structural properties observed after annealing the sample. Electrical measurements showed that excess Zn reduces the conductivity activation energy and increases the conductivity, while excess P up to 15 at.% does not alter the electrical properties significantly.

scholarly journals Detection of X-ray photons by solution-processed lead halide perovskites

2015 ◽  
Vol 9 (7) ◽  
pp. 444-449 ◽  
Author(s):  
Sergii Yakunin ◽  
Mykhailo Sytnyk ◽  
Dominik Kriegner ◽  
Shreetu Shrestha ◽  
Moses Richter ◽  
...  
Keyword(s):  
Solution Processed ◽  
X Ray ◽  
Halide Perovskites ◽  
Lead Halide
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