Nanometer Size Lead Iodide Particles

1992 ◽  
Vol 242 ◽  
Author(s):  
Vivek Mehrotra ◽  
Eric Rodeghiero ◽  
Jens W. OTTO ◽  
Emmanuel P. Giannelis
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
Lead Iodide ◽  
Scanning Calorimetry ◽  
Porous Network ◽  
Nanometer Size ◽  
X Ray ◽  
Quantum Size ◽  
Guest Species

ABSTRACTNanometer size lead iodide particles have been synthesized in the porous network of a cross-linked polymer matrix. The optical band gap of the nanocrystals is shifted towards higher energy as compared to the bulk value. This shift is attributed to the quantum size effect on excitons. Intercalation with aniline leads to a further shift in the band gap which depends on the dipole moment of the intercalated guest species. Differential scanning calorimetry and high temperature x-ray diffraction have been used to analyze the ferroelectric transition in Pbl2.

scholarly journals Flexible ZnO photoelectrode for photo electrochemical energy conversion

2021 ◽  
Author(s):  
T. Shiyani ◽  
Indrani Banerjee ◽  
Santosh K. Mahapatra ◽  
Asim K Ray
Keyword(s):  
Band Gap ◽  
Diffraction Pattern ◽  
Absorption Spectra ◽  
Optical Band Gap ◽  
Solar Fuels ◽  
Photoelectrochemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Pet Substrate

Abstract Photoelectrochemical properties have been investigated for flexible ZnO/ITO/PET photoelectrodes. ZnO was spin coated on ITO/PET substrate with thickness of about 310 nm. The high crystalline structure of ZnO was studied using x-ray diffraction pattern. A value of 3.4 eV has been estimated for optical band gap from its absorption spectra. The flexible ZnO photoelectrode was demonstrated to generate photoelectrochemical current. Values of 1.022 and 0.714 were found to be for photo switching and photoresponsivity, respectively. ZnO/ITO/PET can be used as a substrate for making flexible hybrid PEC devices to generate solar power and solar fuels.

Effect of Tin Composition on Cu2ZnSnS4 Photovoltaic Absorbers

2012 ◽  
Vol 534 ◽  
pp. 156-159 ◽  
Author(s):  
Dong Hua Fan ◽  
Rong Zhang ◽  
Hui Ren Peng
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Band Gap ◽  
Crystallite Size ◽  
Optical Band Gap ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Poor Condition ◽  
Czts Thin Films

Cu2ZnSnS4 (CZTS) thin films are prepared by sulfurizing the precursors deposited by vacuum evaporation methods. The samples sulfurized at 500°C for 3h shows the strong (112) diffraction peak at 28.45˚, suggesting the successful synthesis of CZTS thin films. The X-ray diffraction shows that CZTS thin film prepared in Sn-poor condition have the best crystallinity. The Sn-dependent crystallite size was calculated to be 19.53-21.03 nm. In addition, we found that the optical band gap with various Sn contents can be modulated at 1.48-1.85 eV

Growth, Optical Adsorption and Resistivity of (Ga0.6In0.4)2Se3 and (Ga0.594In0.396Er0.01)2Se3 Single Crystals

2013 ◽  
Vol 200 ◽  
pp. 50-53
Author(s):  
Inna A. Ivashchenko ◽  
Volodumur V. Halyan ◽  
Irina V. Danylyuk ◽  
Volodumur Z. Pankevuch ◽  
Georgij Y. Davydyuk ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Differential Thermal Analysis ◽  
Band Gap ◽  
Single Crystals ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Xrd Method

The phase diagram of the Ga2Se3–In2Se3 system was investigated by differential-thermal analysis (DTA) and X-ray diffraction (XRD) method. The single crystals from the area of existence of the γ2 phase with the compositions (Ga0.6In0.4)2Se3 and (Ga0.594In0.396Er0.01)2Se3 were grown by a vertical Bridgman method. Absorption spectra of the grown crystals were studied. The estimated optical band gap is 1.95±0. 01 eV. The resistance of the single crystals of (Ga0.6In0.4)2Se3 (R=500 MΩ) and (Ga0.594In0.396Er0.01)2Se3 (R=210 MΩ) was measured.

Thin Film InN/Anatase Bilayers as a Substitute Dye/Semiconductor Interface for Solar Cells

2008 ◽  
Vol 1102 ◽  
Author(s):  
Daniel Hoy ◽  
Martin Kordesch
Keyword(s):  
Solar Cell ◽  
High Temperature ◽  
Band Gap ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
Sheet Resistivity ◽  
High Quality ◽  
Semiconductor Interface ◽  
X Ray ◽  
Dye Sensitized

AbstractThe electronic properties of an InN/anatse bilayer, proposed as a replacement for the dye/semi-conductor interface in Dye Sensitized Solar Cell[1, 2], are measured. RF sputtered thin films of anatase and InN are used as the “dye” replacement. . Two types of InN film are prepared: polycrystalline samples deposited at high temperature, with an optical band gap of < 1 eV, and as-deposited (at least partially amorphous) samples with an optical band gap >1 eV. Energy Dispersive X-ray fluorescence, X-ray Diffraction, and Raman spectroscopy are used to characterize the samples. The resistance in the dark and under illumination are measured. The samples deposited at high temperature are crystalline and have a sheet resistivity ≈ 4 Ω/⁐, and display no photoconductivity. The partially amorphous samples have sheet resistivity of ≈ 500Ω/⁐. Since both types of InN films, including high quality (based on band gap) polycrystalline InN, do not show increased conductivity with light, we conclude that a solar cell based on an InN/anatase bilayer is not feasible.

Band-gap engineering in amorphous/microcrystalline ScxGa1-xN.

2001 ◽  
Vol 693 ◽  
Author(s):  
M. E. Little ◽  
M. E. Kordesch
Keyword(s):  
Optical Absorption ◽  
Band Gap ◽  
Absorption Spectra ◽  
Optical Band Gap ◽  
Optical Absorption Spectra ◽  
X Ray Diffraction ◽  
Band Gap Engineering ◽  
X Ray ◽  
Bilayer Films ◽  
Quartz Substrates

AbstractReactive sputtering was used to grow thin films of ScxGa1-xN with scandium concentrations of 20%-70% on quartz substrates at temperatures of 300-675 K. X-ray diffraction (XRD) of the films showed either weak or no structure, suggesting the films are amorphous or microcrystalline. Optical absorption spectra were taken of each sample and the optical band gap was determined. The band gap varied linearly with increasing Ga concentration between 2.0 and 3.5 eV. Ellipsometry was used to confirm the band gap measurements and provide optical constants in the range 250-1200 nm. ScN and GaN have different crystal structures (rocksalt and wurzite, respectively), and thus may form a heterogeneous mixture as opposed to an alloy. Since the XRD data were inconclusive, bilayers of ScN/GaN were grown and optical absorption spectra taken. A fundamental difference in the spectra between the bilayer films and alloy films was seen, suggesting the films are alloys, not herterogeneous mixtures.

scholarly journals Chromium-Induced Nanocrystallization of a-Si Thin Films into the Wurtzite Structure

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
K. Uma Mahendra Kumar ◽  
M. Ghanashyam Krishna
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Nanocrystalline Silicon ◽  
Spectral Transmittance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Silicides ◽  
Crystallite Sizes ◽  
Cr Addition

Chromium metal-induced nanocrystallization of amorphous silicon (a-Si) thin films is reported. The nanocrystalline nature of these films is confirmed from X-ray diffraction and Raman spectroscopy. Significantly, the deconvolution of Raman spectra reveals that the thin films were crystallized in a mixed phase of cubic diamond and wurzite structure as evidenced by the lines at 512 and 496 cm−1, respectively. The crystallite sizes were between 4 to 8 nm. Optical properties of the crystallized silicon, derived from spectral transmittance curves, revealed high transmission in the region above the band gap. Optical band gap varied between 1.3 to 2.0 eV depending on the nature of crystallinity of these films and remained unaltered with increase in Cr addition from 5 to 30%. This signifies that the electronic structure of the nanocrystalline Silicon films is not affected considerably inspite of the presence of metal silicides and the process of crystallization.

scholarly journals Effect of Samarium Nanoparticles on Optical Properties of Zinc Borotellurite Glass System

2016 ◽  
Vol 846 ◽  
pp. 63-68 ◽  
Author(s):  
Saad S. Hajer ◽  
M.K. Halimah ◽  
Azmi Zakaria ◽  
M.N. Azlan
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Fundamental Absorption Edge ◽  
Xrd Analysis ◽  
Ftir Analysis ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
X Ray ◽  
Bonding Parameters ◽  
Optical Energy Band Gap

The glass series of samarium nanoparticles (NPs) doped zinc borotellurite glasses were successfully fabricated by using conventional melt-quenching technique. The structural properties of the prepared glasses were investigated by X-ray diffraction (XRD) analysis and FTIR analysis. It was confirmed that the prepared glasses are amorphous in nature. The bonding parameters of the glasses were analyzed by using FTIR analysis and were found the formation of non-bridging oxygen. The density of these glasses were measured and found to be increased with increasing samarium NPs content. The optical absorption spectra of these glasses were revealed that the fundamental absorption edge shifts to higher wavelengths as the content of Sm2O3 (NPs) increases. The optical energy band gap are found to be decreased linearly with an increasing samarium NPs concentration which is due to the formation of non-bridging oxygen in the glass system.KeywordsBorotellurite glass; optical band gap, Samarium nanoparticles.

Quantum Size Effects of Chemical Bath Deposited ZnSe Thin Films

2013 ◽  
Vol 652-654 ◽  
pp. 1743-1746
Author(s):  
Liang Yan Chen ◽  
Chao Fang
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Absorption Spectrum ◽  
Size Effects ◽  
Optical Band Gap ◽  
Quantum Size Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantum Size ◽  
Znse Thin Films

Quantum dots ZnSe have been deposited through chemical bath deposition in thin films form. The nanoscal grain size of as-deposited and thermal treated ZnSe films have been investigated by X ray Diffraction. And optical band gap of those samples have been obtained from absorption spectrum. Both as-deposited and annealed films were with nanocryatlline grain smaller than the Bohr excitonic radius and showed blue shifts of bandgap in quantum size effects. The blue shifted optical bandgap versus grain size has been modeled theoretically.

Preparation and Characterizations of Nano-Hybrid TiO2/ZnO

2013 ◽  
Vol 832 ◽  
pp. 734-738 ◽  
Author(s):  
S.K.M. Maarof ◽  
M.G.M. Zufrian ◽  
M.F. Achoi ◽  
Mohamad Rusop ◽  
Saifollah Abdullah
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Ultra Violet ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Concentration ◽  
Optimum Sample ◽  
Sample Ratio

This paper will present on preparation and characterizations of hybrid nanoTiO2/ZnO using sol-gel spin coating techniques. The study involved of modification band-gap energy of Titanium Dioxide (TiO2) at different precursor molecular concentration of Zinc oxide (ZnO). The FESEM (Field emission scanning electron microscope) morphological characterize shows TiO2 and ZnO particle produced at nanoscale size. The compositional of both particles confirmed using EDAX (Energy Disperse Analyzer X-ray) analysis. The XRD (X-Ray diffraction) characterize measured the structural properties of anatase and rutile for TiO2 as well as zincite for ZnO. By increasing ZnO molecular concentration, the crystallite size, d were decreased until the optimum sample, ratio of 4 TiO2 : 1 ZnO, with value of 23.71 nm. For UV-VIS (Ultra-Violet/Visible Spectroscopy) measurement, we found the optical band-gap increased with increasing ZnO molecular concentration. The optical band-gap for optimum sample was 3.38 e.V represented this study has successfully improved the optical band-gap of TiO2.

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