Structure, Stability and Vibrational Properties of CdSe Wurtzite Molecules and Nanocrystals: A DFT Study

Abdulsattar, Mudar Ahmed; Abduljalil, Hayder M.; Abed, Hussein Hakim

doi:10.33640/2405-609x.1104

Cited by 10 publications

(7 citation statements)

References 21 publications

(23 reference statements)

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“…Cubic (zinc blende) and hexagonal (wurtzite) structures at the nanoscale regime can be represented by nanostructures called diamondoids and wurtzoids, respectively [6][7][8][9][10]. Clusters and nanostructures from ZnS, ZnSe, CdS, and CdSe have been reported previously by others [11].…”

Section: Methodsmentioning

confidence: 75%

Analysis and Characteristics of Nanostructures for Biomedical Applications

2021

Nanosistemi, Nanomateriali, Nanotehnologii

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The cubic structures of zinc sulphide and ternary alloys from zinc, cadmium, and sulphide atoms at the nanoscale regime have been represented by nanostructures called tetramantane (Zn 11 S 11 , Zn 11n Cd n S 11 (n1, …, 3)). The electronic properties: HOMO, LUMO, and HOMO-LUMO gap have been investigated. They were found as affected by cadmium concentrations and converge to practical results. Infrared and Raman spectra of ternary alloys referred to occur with shifting in maximum peak and appearing a new peak different from infrared and Raman spectra of nanostructure for zinc sulphide due to connecting between zinc, cadmium, and sulphide atoms. UV-Vis spectra for nanostructures have been examined; the maximum peak and the optical-edge absorption are shifted to lower energy. In addition, the width of peaks increase with increased quantity of cadmium atoms. From results, these nanostructures are suitable to be used in optoelectronics and biosensors for biomedical applications. Density functional theory and time-dependent density functional theory at the B3LYP level with SDD-basis functions are used. All the results are obtained by using the Gaussian 09 program.Кубічні структури сульфіду Цинку та тернарних стопів з атомів Цинку, Кадмію та сульфіду на наномасштабному режимі були представлені наноструктурами, званими тетрамантаном (Zn 11 S 11 , Zn 11n Cd n S 11 (n  1, ..., 3)). Досліджено електронні властивості: HOMO, LUMO та HOMO-

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Section: Methodsmentioning

confidence: 75%

Analysis and Characteristics of Nanostructures for Biomedical Applications

2021

Nanosistemi, Nanomateriali, Nanotehnologii

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“…Wurtzite and diamond structure at molecular and nanoscale regimes can be represented by a small molecule called wurtzoid and diamondoid, respectively [21][22][23][24]. The surface atoms of these molecules are usually passivated with hydrogen or other atoms to saturate the dangling bond and make bulk wurtzite and diamond crystals.…”

Section: Models and Methodsmentioning

confidence: 99%

“…However, due to a large number of dangling bonds in both ZnSe and Zn 3 Se 3 molecules for the actual number of bonds of the two molecules, the energy gap is decreased since the dangling bonds create energy levels inside the original energy gap that decreases its value as shown in Table 1. As the molecules increase in size, the number of dangling bonds decreases for the total number of bonds that prevents gap reduction and renders quantum confinement rule of approaching bulk energy gap [24].…”

Section: Energy Gap and Binding Energymentioning

confidence: 99%

Analysis of structural and vibrational properties of ZnSe nanostructures: A DFT/TDDFT study

et al. 2019

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T HE structural and vibrational properties of Zn n Se n (n=1,3,7,13) nanostructures have been investigated using the Gaussian 09 program, density functional theory (DFT) and time-dependent density functional theory (TDDFT) at the B3LYP level with 6-311G basis functions. The structural properties showed that the rebuilding in surface atoms deviated many bonds from their ideal length, the Zn-Se bond length decreased with the increase in the size of nanostructures and converged to the experimental value. Quantum confinement effect diminution was observed with the growing size of the nanostructures; hence, the energy gap converged to the experimental value of 2.7 eV. Moreover, the binding energy increased with the increase of the structure size, such that wurtziod2c (Zn 13 Se 13 ) is more stable than smaller structures. The vibrational properties results indicated that the experimental longitudinal optical mode (LO mode) is situated between bare and hydrogen passivated LO modes and very near to the bare case, this gave a good agreement with experimental findings. The presence of hydrogen atoms at the surface caused a several times decrease in vibrational force constant in comparison to the bare case. The IR spectrum for wurtzoid and HP wurtzoid were investigated. The optical edge in UV-Vis spectra of wurtzoid reduced from 4.5 eV to 4.2 eV of wurtzoid2c due to the increase in the size of the nanostructure, while the maximum peak for wurtzoid at 2.88 eV increased to 3.06 eV for wurtzoid2c showing a clear blue shift. These results leads to wide applications in fields such as photoelectronic devices, lasers, sensors, and LEDs.

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“…Therefore, these are reasons for these nanomaterials to be used in many practical and biomedical applications [1][2][3]. Currently, there is a significant theoretical and experimental interest in chalcogenides due to their various applications in science and technology [4][5][6][7][8][9]. Zinc sulfide and zinc selenide at the nanoscale regime having beneficial optical and electrical properties; therefore, it is used in different fields such as mid-infrared laser applications, photocatalysts, and sensors [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Analysis of electronic, Raman and UV-vis spectra for Zn11Se11, Zn11S11, and ternary alloys Zn11SnSe11-n(n= 1-11) A DFT/TDDFT study.

2020

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Zn 11 Se 11 , Zn 11 S 11 , and ternary alloys from Zn 11 S n Se 11-n (n = 1-11), with cubic structures represented by nanostructures called tetramantane, have been studied theoretically by investigating the electronic properties, Raman and UV-vis spectra. LUMO and HOMO levels were observed to change with the number of the sulfur atoms. The (HOMO-LUMO) gap for Zn 11 Se 11 (2.377205eV) increased with the sulfur atoms. Zn 11 S 8 Se 3 have an energy gap (3.061305eV) less than others ternary alloys. The calculated energy gap of Zn 11 S 11 (3.597374eV) is in a high agreement with experimental value (3.6 eV). Raman spectra for ternary alloys Zn 11 S n Se 11-n content peaks result from the connection of (Zn 11 Se 11 +Zn 11 S 11) peaks, Zn 11 Se 11 has peak at 260.42 cm-1 shifts from the experimental value by a small deviasion which is produced due to the confinement effect. UV-vis spectra for ternary alloys shifted to a higher energy level with the increase in the number of sulfur atoms and dramatically close to Zn 11 S 11 UV-vis spectrum except Zn 11 S 8 Se 3 has λ max at 342 nm. These nanostructures are suitable to be used in different applications such as lenses, photoelectronic devices, solar energy, and biosensors. DFT/TDDFT at the B3LYP level with SDD basis functions is used. All the calculations are completed using the Gaussian 09 program.

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Structure, Stability and Vibrational Properties of CdSe Wurtzite Molecules and Nanocrystals: A DFT Study

Cited by 10 publications

References 21 publications

Analysis and Characteristics of Nanostructures for Biomedical Applications

Analysis and Characteristics of Nanostructures for Biomedical Applications

Analysis of structural and vibrational properties of ZnSe nanostructures: A DFT/TDDFT study

Analysis of electronic, Raman and UV-vis spectra for Zn11Se11, Zn11S11, and ternary alloys Zn11SnSe11-n(n= 1-11) A DFT/TDDFT study.

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