IHJPAS. 36 (3) 2023 148 This work is licensed under a Creative Commons Attribution 4.0 International License O Nanoparticle Structural 2The Effect of Annealing Temperatures on Cu Properties karrar.Ameen1104a@ihcoedu.uobaghdad.edu.iq :Corresponding author* Abstract In this study, the effect of the annealing temperature on the material properties and the structural properties of cuprous oxide was studied in order to investigate how the annealing temperature affects the material properties, and the temperature varied between 200℃, 300℃, 400℃ and 500 ℃ and was unannealed. The physical properties of the cuprous oxide were measured by X-ray diffraction (XRD). The XRD patterns showed that the Cu2O nanoparticles were highly pure, crystalline, and nano-sized. From the XRD results, we found the pure cuprite (Cu2O) phase. The values of crystal size were discovered and calculated by the Halder-Wagner and Size-Strain Plot (SSP) methods, respectively. The crystallite size increased as the annealing temperature increased. As a result, it was discovered that annealing temperature has a significant impact on structural and morphological aspects. In order to calculate physical and microstructural parameters such as internal strain, dislocation density, surface area, and consequently the number of unit cells, the sample was taken into consideration. keywords: Cu2O, Originpro, Xrd, halder-wagner, size-strain plot. 1. Introduction Great importance is given to the preparation of nanoparticles (NPs) and the study of their properties [1]. Their physical and chemical properties attract the current scientific field over bulk materials [2]. Cuprous oxide (Cu2O) is a p-type transparent semiconductor material with a unit cell containing four oxygen and two copper ions with a cubic structure belonging to the Pn3m space group. The lattice parameters are a,b and c = 4.2696 Å [3]. Many processes have been used for the synthesis of Cu2O nanostructures. Is currently attracting considerable interest within the fields of both condensed matter physics and materials chemistry. This interest is especially to do with its rich doi.org/10.30526/36.3.3116 Article history: Received 27 November 2022, Accepted 18 January 2023, Published in July 2023. Ibn Al-Haitham Journal for Pure and Applied Sciences Journal homepage: jih.uobaghdad.edu.iq Khalid H. Harbbi Department of Physics, College of Education for Pure Science Ibn-AL-Haitham, University of Baghdad, Baghdad, Iraq. Khalid.h.h@ihcoedu.uobaghdadmedu.iq Karrar A. Alsoltani* Department of Physics, College of Education for Pure Science Ibn-AL-Haitham, University of Baghdad, Baghdad, Iraq. karrar.Ameen1104a@ihcoedu.uobaghdad.edu.iq https://creativecommons.org/licenses/by/4.0/ mailto:karrar.Ameen1104a@ihcoedu.uobaghdad.edu.iq mailto:Khalid.h.h@ihcoedu.uobaghdadmedu.iq mailto:Khalid.h.h@ihcoedu.uobaghdadmedu.iq mailto:karrar.Ameen1104a@ihcoedu.uobaghdad.edu.iq mailto:karrar.Ameen1104a@ihcoedu.uobaghdad.edu.iq IHJPAS. 36 (3) 2023 149 excitonic structure and potential applications in solar energy conversion, catalysis, sensing, magnetic storage medium, and electrode materials in lithium-ion batteries, etc.[4-5]. In this work nanopowder of Cu2O with different annealing temperatures Cu2O powder that has not been annealed as well as powder that has been annealed at 200, 300, 400, and 500°C have been used to explore the impact of annealing temperature on structural characteristics using X-ray diffraction (XRD), and the results have been compared and discussed. 2. Theory 2.1. Method of Halder-Wagner In the method of Halder-Wagne where Gauss and Lorentzian describe the strain and crystallite size profiles [6]. ( 𝛽ℎ𝑘𝑙 ∗ 𝑑ℎ𝑘𝑙 ∗ ) 2 = ( 1 D ) ( 𝛽ℎ𝑘𝑙 ∗ 𝑑ℎ𝑘𝑙 ∗ 2 ) + ( ε 2 )2 (1) Where The wavelength of the X-ray plot was ( 𝛽ℎ𝑘𝑙 ∗ 𝑑ℎ𝑘𝑙 ∗ ) 2 against ( 𝛽ℎ𝑘𝑙 ∗ 𝑑ℎ𝑘𝑙 ∗ 2 ) is a straight line. where β*hkl = β cos 𝜃 / λ and d*hkl = 2sinθ /λ. The inverse slope of the line was used to get the mean diameter. The y-intercept yields the strain distortions.[7-8]. 2.2. Size-strain Plot Method The low and medium angle ranges are given more weight in this method, which is advantageous because the overlap between the diffraction peaks is greatly decreased. Now, the relationship between lattice strain and crystal size is provided by [9] using the size-strain plot technique. (dhklβhklcosθ) 2 = ( K D ) (dhkl 2 βhklcosθ) + (2ε) 2 (2) Where (𝛽h𝑘𝑙 / 𝑑h𝑘𝑙)2 denotes the X axis and (𝛽h𝑘𝑙 /𝑑2h𝑘𝑙)2 denotes the Y axis. The slope yields the mean crystal size value, and the intersection yields the strain. 3. Results and Discussion According to the XRD patterns shown in Figure 1, the XRD pattern is shown with angles ranging from 10 to 80. Obtained from source , shows in situ for samples 1-5. Through a program (WebPlotDigitizer-4.5), we obtain data for intensity and 2𝜃 of Cu2O nanoparticles to all profile lines it is possible to index five peaks at 2θ = 29.78°, 36.56°, 42.39°, 62.51°, and 73.46° at the (110), (111), (200), (220) and (311) planes of the cubic phase Cu2O with a lattice constant of equal 0.426 6 nm [10]. These values are very close to those values in International Centre for Diffraction Data JCPDS (PDF, Powder Diffraction File, No. 0 5–0 6 6 7, 1996) [10]. IHJPAS. 36 (3) 2023 150 Figure1. XRD patterns of Cu2O nanoparticles were un and annealed at 200℃, 300℃, 400℃ and 500 ℃ In addition, this data is used to draw the shape of the peaks using an analytical program (Origin Pro Lab) to calculate the area under the curve and the FWHM is calculated by the program and then calculate integral breadth was the integral breadth which is [11]: β = A / Io (3) Where A was the area under the curve and the Io was the highest intensity of the peak for each sample and for the different peaks respectively. The below Figures and tables get from an (Origin Pro Lab). These findings will be used to apply the previous equations to compute each crystal's sizes and strains in order to understand how the annealing temperature affects them. Table 1. result of Cu2O NPs unannealed by Originpro Figure2. XRD patterns of Cu2O nanoparticles unannealed by Originpro ( h k l ) 2θ un Area FWHM Height β ( 1 1 0) 29.78 28.64926 0.76338 33.53435 0.854326 ( 1 1 1 ) 36.56 437.6825 0.97852 369.031 1.186032 ( 2 0 0 ) 42.39 138.7683 0.83286 113.909 1.218239 ( 2 2 0 ) 62.51 94.84389 0.75674 88.90931 1.066749 ( 3 1 1 ) 73.46 23.95065 0.42235 55.96132 0.427986 IHJPAS. 36 (3) 2023 151 Table 2. result of Cu2O NPs annealed at 200°C by Originpro Figure3. XRD patterns of Cu2O nanoparticles annealed at 200° C by Originpro Table 3. result of Cu2O NPs annealed at 300°C by Originpro Figure4. XRD patterns of Cu2O nanoparticles annealed at 300° C by Originpro Table 4. result of Cu2O NPs annealed at 400°C by Originpro Figure5. XRD patterns of Cu2O nanoparticles annealed at 400° C by Originpro ( h k l ) 2θ 200°C Area FWHM Height β ( 1 1 0) 29.78 8.1628 0.1946 20.209 0.4039 ( 1 1 1 ) 36.56 403.51 1.0999 345.43 1.1681 ( 2 0 0 ) 42.39 117.91 0.6298 115.74 1.0187 ( 2 2 0 ) 62.51 175.00 0.9893 103.06 1.698 ( 3 1 1 ) 73.46 74.599 1.7634 37.541 1.9871 ( h k l ) 2θ 300°C Area FWHM Height β ( 1 1 0) 29.78 56.228 0.4707 63.832 0.8809 ( 1 1 1 ) 36.56 611.52 0.8144 601.74 1.0163 ( 2 0 0 ) 42.39 212.6 0.8646 203.99 1.0421 ( 2 2 0 ) 62.51 134.82 1.2737 92.909 1.4511 ( 3 1 1 ) 73.46 103.05 2.2347 53.819 1.9147 ( h k l ) 2θ 400°C Area FWHM Height β ( 1 1 0) 29.78 26.471 0.1204 119.63 0.2213 ( 1 1 1 ) 36.56 955.57 0.4433 1985.1 0.4814 ( 2 0 0 ) 42.39 386.95 0.4426 598.64 0.6464 ( 2 2 0 ) 62.51 222.64 0.5325 386.44 0.5761 ( 3 1 1 ) 73.46 168.43 0.6323 231.32 0.7281 IHJPAS. 36 (3) 2023 152 Table 5. result of Cu2O NPs annealed at 500°C by Originpro Figure6. XRD patterns of Cu2O nanoparticles annealed at 500° C by Originpro 3.1. Determination of crystallite size and the lattice strain 3.1.1. Halder-wagner method After calculate the integral breadth of all peak for all five sample then we use equations d*hkl = 2sinθ /λ and β*hkl = β cos 𝜃 / λ where λ the wavelength of the X-ray (0.15046) and plot ( 𝛽ℎ𝑘𝑙 ∗ 𝑑ℎ𝑘𝑙 ∗ ) 2 against ( 𝛽ℎ𝑘𝑙 ∗ 𝑑ℎ𝑘𝑙 ∗ 2 ) then fitting the data by straight line to compare eq (1) by getting straight line equation to obtained crystallite size and the lattice strain. The outcomes are presented in Tables (6). ( h k l ) 2θ 500°C Area FWHM Height β ( 1 1 0) 29.78 50.235 0.1890 156.85 0.3203 ( 1 1 1 ) 36.56 1080.1 0.2808 2632.6 0.4103 ( 2 0 0 ) 42.39 349.25 0.4257 708.92 0.4927 ( 2 2 0 ) 62.51 323.47 0.6781 432.18 0.7485 ( 3 1 1 ) 73.46 175.41 0.5114 304.68 0.5757 IHJPAS. 36 (3) 2023 153 Figure 7. Halder-Wagner method for each sample respectively Table 6. result of crystallite size and the lattice strain by Halder-Wagner method for all Cu2O NPs sample sample D nm 𝛆 strain Cu2O un-annealed 8.69 0.008 Cu2O at 200°c 9.73 0.034 Cu2O at 300°c 17.69 0.056 Cu2O at 400°c 19.6 0.01 Cu2O at 500°c 40.27 0.022 From the above five graphic figures, it is clear that by increasing the integrated width, it leads to an increase in the slope of the curve for each of the shapes, and this was actually found by calculating the particle size in this method. The annealing of Cu2O nanoparticles shows that the higher the annealing temperature, the more highly oriented (111) planes could be formed with increasing annealing temperature. i. Size-strain plot method Each diffraction line's crystallite size is calculated using this method, and Equation (2) represents We can see in this technique an inverse relationship between crystal size and strain where (𝛽h𝑘𝑙 / 𝑑h𝑘𝑙)2 represents the X axis, (𝛽h𝑘𝑙 /𝑑2h𝑘𝑙)2 represents the Y axis, and d2hklBhklcos θ computed in IHJPAS. 36 (3) 2023 154 radians and utilizes a wavelength of X-ray equal to 0.15046 as shown in Figure 8. The outcomes were computed and are shown in Table (7). Figure 8. Size-strain plot method for each sample respectively IHJPAS. 36 (3) 2023 155 Table 7. Result of crystallite size and the lattice strain Size-strain plot method for all Cu2O NPs sample sample D nm strain Cu2O un-annealed 7.76 0.001 Cu2O at 200°c 8.66 0.005 Cu2O at 300°c 15.74 0.009 Cu2O at 400°c 16.19 0.001 Cu2O at 500°c 38.41 0.004 Also, in this method, the integral intensity change depends on the change in the temperature of each curve, and therefore there is a change in the value of the particle size, but here the effect of the shape coefficient value appears on the result. From XRD we can work out the density of x-ray of the powders by using this equation [12]: ρ =Z Mw /V Nav (4) Where ρ: the density (g/cm3), Mw: molar mass 143.091 (g/mol) for Cu2O, Z: the number of atoms: unit cell volume (cm3), and Nav: Avogadro number (1/mol) [13] To calculate volume for the cubic structure, lattice parameters can be calculated from: 1 dhkl 2 = (h + k + l ) 1 𝑎2⁄ ⁄ (5) Where dhkl=λ/(2sinθ) d-spacing (Å) and h, k, and l are all integers, (hkl) is the lattice plane index, and a is lattice constants. So the volume of Cu2O is equal 76.96263 Å3 and density 6.03 (g/cm 3) The surface area can be determined by following equation [14]: S.A=6 *103/D ρ (6) And we can find dislocation density (δ) and number of unit cells (n) is calculated using the relation [15,16]: δ=1/D2 (7) n = π D3 /6 V (8) Their calculated values will be presented in Table 8. Table 8. Shows lattice parameter, X-ray and dislocations density, surface area, and number of unit cells for all Cu2O NPs sample sample Cu2O un-annealed Cu2O at 200°c Cu2O at 300°c Cu2O at 400°c Cu2O at 500°c S.A (m2/g) 114.5 102.26 56.25 50.77 24.71 δ(1/m2) *1016 1.32422 1.05627 0.319554 0.260308 0.0616647 n 4464.55 6266.96 37661.9 51225.59 444287 IHJPAS. 36 (3) 2023 156 4. Conclusions We can conclude from the results obtained for both methods (Halder-wagner and Size-strain plot) that increasing the temperature has a clear effect on the width of the middle of the intensity and thus an effect on increasing the particle size for both methods combined, but the increase in particle size in the T method is less due to the presence of a direct effect of the shape factor in the mathematical formula in this way. Also, there is a regular increase in the strain when observing the calculated values for this strain and for three temperatures in both methods. 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