scholarly journals Structural Disorder in Layered Hybrid Halide Perovskites: Types of Stacking Faults, Influence on Optical Properties and Their Suppression by Crystallization Engineering

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3333
Author(s):  
Andrei S. Tutantsev ◽  
Ekaterina I. Marchenko ◽  
Natalia N. Udalova ◽  
Sergey A. Fateev ◽  
Eugene A. Goodilin ◽  
...  
Keyword(s):  
Optical Properties ◽  
Stacking Faults ◽  
Structural Disorder ◽  
Model System ◽  
Thickness Variation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Simple Addition ◽  
Halide Perovskites ◽  
Xrd Patterns

Layered hybrid halide perovskites (LHHPs) are an emerging type of semiconductor with a set of unique optoelectronic properties. However, the solution processing of high-quality LHHPs films with desired optical properties and phase composition is a challenging task, possibly due to the structural disorder in the LHHP phase. Nevertheless, there is still a lack of experimental evidence and understanding of the nature of the structural disorder in LHHPs and its influence on the optical properties of the material. In the current work, using 2D perovskites (C4H9NH3)2(CH3NH3)n−1PbnI3n+1 (further BA2MAn−1PbnI3n+1) with n = 1–4 as a model system, we demonstrate that deviations in LHHPs optical properties and X-ray diffraction occur due to the presence of continuous defects—Stacking Faults (SFs). Upon analyzing the experimental data and modeled XRD patterns of a possible set of stacking faults (SFs) in the BA2MAPb2I7 phase, we uncover the most plausible type of SFs, featured by the thickness variation within one perovskite slab. We also demonstrate the successful suppression of SFs formation by simple addition of BAI excess into BA2MAn−1PbnI3n+1 solutions.

Effects of Indium Incorporation on the Optical Properties of ZnO Films

2006 ◽  
Vol 11-12 ◽  
pp. 159-162 ◽  
Author(s):  
Yong Ge Cao ◽  
Lei Miao ◽  
Sakae Tanemura ◽  
Yasuhiko Hayashi ◽  
Masaki Tanemura
Keyword(s):  
Optical Transmission ◽  
Full Width Half Maximum ◽  
Structural Disorder ◽  
Band Gaps ◽  
Zno Films ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optical Band Gaps ◽  
Xrd Patterns

Transparent indium-doped ZnO (IZO) films with low In content (<6at%) were fabricated through radio-frequency (rf) helicon magnetron sputtering. Formation of In-Zn-O solid solution was confirmed by X-ray diffraction (XRD) patterns. Incorporation of indium into ZnO films enhances the optical transmission in the visible wavelength. The optical band-gaps slightly increase from 3.25eV (ZnO) to 3.28eV (In0.04Zn0.96O) and to 3.30eV (In0.06Zn0.94O) due to Burstain-Moss effect. The Urbach tail parameter E0, which is believed to be a function of structural disorder, increases from 79meV (ZnO), to 146meV (In0.04Zn0.96O), and to 173meV (In0.06Zn0.94O), which is consistent with increase of Full-Width Half-Maximum (FWHM) in corresponding XRD patterns. Decreasing in crystal quality with increasing indium concentration is also confirmed by photoluminescence spectra.

Synthesis and Optical Properties of Eu3+ Doped NaYF4 and KYF4 Micro/Nanocrystals

2016 ◽  
Vol 16 (4) ◽  
pp. 3857-3860 ◽  
Author(s):  
Siling Guo ◽  
Chunyan Cao ◽  
Renping Cao
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Local Environment ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Two Samples ◽  
Xrd Patterns ◽  
The Eu

Through a hydrothermal method, 1 mol% Eu3+ doped NaYF4 and KYF4 micro/nanocrystals have been synthesized. The materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images, room temperature photoluminescence (PL) excitation and emission spectra, and luminescent dynamic decay curves. The XRD analysis suggested the crystalline structures of the obtained samples. The FE-SEM images indicated the morphology and size of the obtained samples. The PL spectra illustrate the optical properties of Eu3+ in the two samples. Since it is sensitive to the local environment of the ion, the Eu3+ presents different optical properties in the NaYF4 and KYF4 materials.

Structural and Photocatalytic Properties of Fe-Dope TiO2 Nanostructure Using the Hydrothermal Treatment Method

2013 ◽  
Vol 634-638 ◽  
pp. 2261-2263
Author(s):  
Khun Ngern Supunnee ◽  
Vatcharinkorn Mekla ◽  
Eakkarach Raksasri
Keyword(s):  
Optical Properties ◽  
Hydrothermal Treatment ◽  
Treatment Method ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Cuo Nanostructure ◽  
Uv Visible ◽  
Xrd Patterns ◽  
Top View

In this work optical properties of CuO nanostructure were studied. CuO nanostructure were synthesized by the hydrothermal treatment method. The structural and chemical natures of the obtained materials were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and study optical properties by UV-visible spectral. The XRD patterns of the CuO nanostructures indicated that CuO phases (JCPDS 05- 0661). The top-view SEM images, it can be seen clearly that high-density, horizontally scattered nanorod were grown on the product prepared at concentration of NaOH (aq) 7.5 M at 180 C for 12 h. The spectral of UV-vis data recorded showed the strong cut off at 341 nm.

scholarly journals Chemical Vapor Deposited Mixed Metal Halide Perovskite Thin Films

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3526
Author(s):  
Siphesihle Siphamandla Magubane ◽  
Christopher Joseph Arendse ◽  
Siphelo Ngqoloda ◽  
Franscious Cummings ◽  
Christopher Mtshali ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Coverage ◽  
Chemical Vapor ◽  
Reaction Chamber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cvd Method ◽  
Metal Halide Perovskite ◽  
Chemical Vapor Deposited ◽  
Xrd Patterns

In this article, we used a two-step chemical vapor deposition (CVD) method to synthesize methylammonium lead-tin triiodide perovskite films, MAPb1−xSnxI3, with x varying from 0 to 1. We successfully controlled the concentration of Sn in the perovskite films and used Rutherford backscattering spectroscopy (RBS) to quantify the composition of the precursor films for conversion into perovskite films. According to the RBS results, increasing the SnCl2 source amount in the reaction chamber translate into an increase in Sn concentration in the films. The crystal structure and the optical properties of perovskite films were examined by X-ray diffraction (XRD) and UV-Vis spectrometry. All the perovskite films depicted similar XRD patterns corresponding to a tetragonal structure with I4cm space group despite the precursor films having different crystal structures. The increasing concentration of Sn in the perovskite films linearly decreased the unit volume from about 988.4 Å3 for MAPbI3 to about 983.3 Å3 for MAPb0.39Sn0.61I3, which consequently influenced the optical properties of the films manifested by the decrease in energy bandgap (Eg) and an increase in the disorder in the band gap. The SEM micrographs depicted improvements in the grain size (0.3–1 µm) and surface coverage of the perovskite films compared with the precursor films.

scholarly journals The structure and optical properties of organic semiconductor bulk hetrojunction blend (NiPcTs/Alq3) thin films

2019 ◽  
Vol 15 (33) ◽  
pp. 40-48
Author(s):  
Atyaf H. Kadhum
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Optical Properties ◽  
Spin Coating ◽  
Annealing Temperature ◽  
Bulk Heterojunction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible ◽  
Xrd Patterns

The effect of heat treatment on the optical properties of the bulk heterojunction blend nickel (II) phthalocyanine tetrasulfonic acid tetrasodium salt and Tris (8-hydroxyquinolinato) Aluminum (NiPcTs/Alq3) thin films which prepared by spin coating was described in this study. The films coated on a glass substrate with speed of 1500 rpm for 1.5 min and treated with different annealing temperature (373, 423 and 473) K. The samples characterized using UV-Vis, X ray diffraction and Fourier transform Infrared (FTIR) spectra, XRD patterns indicated the presence of amorphous and polycrystalline blend (NiPcTs/Alq3). The results of UV visible shows that the band gap increase with increasing the annealing temperature up to 373 K and decreases with increase the annealing temperature to (423, 473)K respectively.

Structure Characterisation and Optical Properties of Eu3+-Doped LaAlO3

2013 ◽  
Vol 745-746 ◽  
pp. 136-141 ◽  
Author(s):  
Gang Wu ◽  
Hong Mei Deng ◽  
Nuo Fan Ding ◽  
Hu Rui Yan ◽  
Ping Xiong Yang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Reflection Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Mixing ◽  
Mixing Method ◽  
Higher Temperature ◽  
Xrd Patterns

In this paper, Eu3+-doped LaAlO3 powders which with the concentration of Eu3+ in the range of 0~5% were prepared by a new liquid mixing method. The structure of the LaAlO3 powders were investigated by X-ray diffraction (XRD), and the influence of the increase of temperature on the crystal structure were also studied. We found that the powders crystallized above 800 which means higher temperature can improve the crystallization. The influences of the increasing Eu3+ concentration were also studied through the XRD patterns. The average sizes of the samples were also calculated by the Sherrer equation. The optical properties of different concentration of Eu3+-doped LaAlO3 particles were investigated through the reflection spectra.

Structural and Photocatalytic Properties of CuO Nanorods Using the Hydrothermal Treatment Method

2013 ◽  
Vol 634-638 ◽  
pp. 2258-2260
Author(s):  
Sopa Noontasa ◽  
Vatcharinkorn Mekla ◽  
Sert Kiennork
Keyword(s):  
Optical Properties ◽  
Hydrothermal Treatment ◽  
Treatment Method ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Cuo Nanostructure ◽  
Uv Visible ◽  
Xrd Patterns ◽  
Top View

In this work optical properties of CuO nanostructure were studied. CuO nanostructure were synthesized by the hydrothermal treatment method. The structural and chemical natures of the obtained materials were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and study optical properties by UV-visible spectral. The XRD patterns of the CuO nanostructures indicated that CuO phases (JCPDS 05- 0661). The top-view SEM images, it can be seen clearly that high-density, horizontally scattered nanorod were grown on the product prepared at concentration of NaOH (aq) 7.5 M at 180 C for 12 h. The spectral of UV-vis data recorded showed the strong cut off at 341 nm.

Defect structures of Nb1+αS2 sulfidation scales

1992 ◽  
Vol 50 (1) ◽  
pp. 38-39
Author(s):  
Chuxin Zhou ◽  
L. W. Hobbs
Keyword(s):  
Stacking Faults ◽  
Rhombohedral Structure ◽  
Stacking Sequence ◽  
Defect Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plane Normal ◽  
Lower Case ◽  
Sulfur Layer ◽  
Two Phases

One of the major purposes in the present work is to study the high temperature sulfidation properties of Nb in severe sulfidizing environments. Kinetically, the sulfidation rate of Nb is satisfactorily slow, but the microstructures and non-stoichiometry of Nb1+αS2 challenge conventional oxidation/sulfidation theory and defect models of non-stoichiometric compounds. This challenge reflects our limited knowledge of the dependence of kinetics and atomic migration processes in solid state materials on their defect structures.Figure 1 shows a high resolution image of a platelet from the middle portion of the Nb1+αS2 scale. A thin lamellar heterogeneity (about 5nm) is observed. From X-ray diffraction results, we have shown that Nb1+αS2 scale is principally rhombohedral structure, but 2H-NbS2 can result locally due to stacking faults, because the only difference between these 2H and 3R phases is variation in the stacking sequence along the c axis. Following an ABC notation, we use capital letters A, B and C to represent the sulfur layer, and lower case letters a, b and c to refer to Nb layers. For example, the stacking sequence of 2H phase is AbACbCA, which is a ∼12Å period along the c axis; the stacking sequence of 3R phase is AbABcBCaCA to form an ∼18Å period along the c axis. Intergrowth of these two phases can take place at stacking faults or by a shear in the basal plane normal to the c axis.

Structural and optical properties of Tin Oxide and Indium doped SnO2 thin films deposited by thermal evaporation technique

2016 ◽  
Vol 12 (3) ◽  
pp. 4394-4399
Author(s):  
Sura Ali Noaman ◽  
Rashid Owaid Kadhim ◽  
Saleem Azara Hussain
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Tin Oxide ◽  
Thermal Evaporation ◽  
Pure Sno2 ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Evaporation Technique ◽  
Sno2 Thin Films

Tin Oxide and Indium doped Tin Oxide (SnO2:In) thin films were deposited on glass and Silicon  substrates  by  thermal evaporation technique.  X-ray diffraction pattern of  pure SnO2 and SnO2:In thin films annealed at 650oC and the results showed  that the structure have tetragonal phase with preferred orientation in (110) plane. AFM studies showed an inhibition of grain growth with increase in indium concentration. SEM studies of pure  SnO2 and  Indium doped tin oxide (SnO2:In) ) thin films showed that the films with regular distribution of particles and they have spherical shape.  Optical properties such as  Transmission , optical band-gap have been measured and calculated.

scholarly journals Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 937
Author(s):  
Yingying Hu ◽  
Md Rasadujjaman ◽  
Yanrong Wang ◽  
Jing Zhang ◽  
Jiang Yan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Crystal Size ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Flow Rates ◽  
X Ray ◽  
N2 Flow Rate

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.

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