scholarly journals Absorption and Isomerization of Azobenzene Guest Molecules in Polymeric Nanoporous Crystalline Phases

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 1074-1088
Author(s):  
Nicola Coscia ◽  
Antonietta Cozzolino ◽  
Manohar Golla ◽  
Paola Rizzo
Keyword(s):  
Thin Films ◽  
Amorphous Phase ◽  
Spectroscopic Analysis ◽  
Crystalline Phases ◽  
Guest Molecules ◽  
Uv Visible

PPO co-crystalline (CC) films including azobenzene guest molecules have been prepared and characterized by WAXD, FTIR and UV-Visible measurements. Isomerization reactions of azobenzene (photo-induced trans to cis and spontaneous cis to trans) included in α and β nanoporous-crystalline (NC) phases leading to CC phases, or simply absorbed in amorphous phase have been studied on thick and thin films. Spectroscopic analysis shows that photo-isomerization of azobenzene occurs without expulsion of azobenzene guest molecules from crystalline phases. Sorption studies of α and β NC films immersed into photo-isomerized azobenzene solution reveal a higher selectivity of the β NC phase toward cis azobenzene isomer than the α NC phase, inducing us to propose the β NC phase as particularly suitable for absorbing spherically bulky guest molecules.

scholarly journals Polymer Composites with 0.98 Transparencies and Small Optical Energy Band Gap Using a Promising Green Methodology: Structural and Optical Properties

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1648
Author(s):  
Muaffaq M. Nofal ◽  
Shujahadeen B. Aziz ◽  
Jihad M. Hadi ◽  
Wrya O. Karim ◽  
Elham M. A. Dannoun ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Polymer Composites ◽  
Amorphous Phase ◽  
Absorption Edge ◽  
Complex Form ◽  
Bandgap Energy ◽  
Optical Parameters ◽  
Visible Spectroscopy ◽  
Uv Visible

In this work, a green approach was implemented to prepare polymer composites using polyvinyl alcohol polymer and the extract of black tea leaves (polyphenols) in a complex form with Co2+ ions. A range of techniques was used to characterize the Co2+ complex and polymer composite, such as Ultraviolet–visible (UV-Visible) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The optical parameters of absorption edge, refractive index (n), dielectric properties including real and imaginary parts (εr, and εi) were also investigated. The FRIR and XRD spectra were used to examine the compatibility between the PVA polymer and Co2+-polyphenol complex. The extent of interaction was evidenced from the shifts and change in the intensity of the peaks. The relatively wide amorphous phase in PVA polymer increased upon insertion of the Co2+-polyphenol complex. The amorphous character of the Co2+ complex was emphasized with the appearance of a hump in the XRD pattern. From UV-Visible spectroscopy, the optical properties, such as absorption edge, refractive index (n), (εr), (εi), and bandgap energy (Eg) of parent PVA and composite films were specified. The Eg of PVA was lowered from 5.8 to 1.82 eV upon addition of 45 mL of Co2+-polyphenol complex. The N/m* was calculated from the optical dielectric function. Ultimately, various types of electronic transitions within the polymer composites were specified using Tauc’s method. The direct bandgap (DBG) treatment of polymer composites with a developed amorphous phase is fundamental for commercialization in optoelectronic devices.

Layered Nonstoichiometric V7O16 Thin Films with Controlled Oxygen-Deficient Multivalent States and Crystalline Phases

2019 ◽  
Vol 1 (11) ◽  
pp. 2308-2313
Author(s):  
Menghui Yuan ◽  
Tiantian Huang ◽  
Shuxia Wang ◽  
Rui Zhang ◽  
Yan Yang ◽  
...  
Keyword(s):  
Thin Films ◽  
Crystalline Phases

Epitaxial Growth of AlN Thin Films on Silicon and Sapphire by Pulsed Laser Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
R.D. Vispute ◽  
H. Wu ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Pulsed Laser Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Breakdown Field ◽  
Transmission Electron ◽  
Uv Visible ◽  
Relationship Of

ABSTRACTAIN thin films have been grown epitaxially on Si(111) and Al2O3(0001) substrates by pulsed laser deposition. These films were characterized by FTIR and UV-Visible, x-ray diffraction, high resolution transmission electron and scanning electron microscopy, and electrical resistivity. The films deposited on silicon and sapphire at 750-800°C and laser energy density of ∼ 2 to 3J/cm2 are epitaxial with an orientational relationship of AIN[0001]║ Si[111], AIN[2 110]║Si[011] and AlN[0001]║Al2O3[0001], AIN[1 2 1 0]║ Al2O3[0110] and AIN[1010] ║ Al2O3[2110]. The both AIN/Si and AIN/Al2O3 interfaces were found to be quite sharp without any indication of interfacial reactions. The absorption edge measured by UV-Visible spectroscopy for the epitaxial AIN film grown on sapphire was sharp and the band gap was found to be 6.1eV. The electrical resistivity of the films was about 5-6×l013Ω-cm with a breakdown field of 5×106V/cm. We also found that the films deposited at higher laser energy densities ≥10J/cm2 and lower temperatures ≤650°C were nitrogen deficient and containing free metallic aluminum which degrade the microstructural, electrical and optical properties of the AIN films

Thermal conversion of CBD grown ZnS thin films to ZnO

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Kooliyankal Naseema ◽  
Kaniyamkandy Ribin ◽  
Nidiyanga Navya ◽  
Prasoon Prasannan
Keyword(s):  
Thin Films ◽  
Low Cost ◽  
Thermal Conversion ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Glass Substrates ◽  
Anion Substitution ◽  
Nano Crystalline ◽  
Before And After ◽  
Uv Visible

AbstractNano crystalline zinc sulfide thin films were deposited onto glass substrates by chemical bath deposition method. One of the samples was annealed at 300 °C for 2 h in air using a muffle furnace. The prepared thin films were investigated by X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM) and Raman spectroscopy (FT-R) studies before and after annealing. The analysis confirmed the thermal-induced anion substitution and conversion of ZnS crystal to ZnO wurtzite crystal. XRD pattern showed that these films were phase pure and polycrystalline in nature. Optical band gap was found to be 3.86 eV for ZnS and 3.21 eV for ZnO. The films prepared by this simple, low-cost technique are suitable for photovoltaic and optoelectronic applications.

Optical properties of anatase TiO2 films modified by N ion implantation

2012 ◽  
Vol 90 (1) ◽  
pp. 39-43 ◽  
Author(s):  
X. Xiang ◽  
D. Chang ◽  
Y. Jiang ◽  
C.M. Liu ◽  
X.T. Zu
Keyword(s):  
Thin Films ◽  
Ion Implantation ◽  
Photoelectron Spectroscopy ◽  
Radio Frequency Magnetron Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Light Region ◽  
Uv Visible ◽  
Substrate Temperatures

Anatase TiO2 thin films are deposited on K9 glass samples at different substrate temperatures by radio frequency magnetron sputtering. N ion implantation is performed in the as-deposited TiO2 thin films at ion fluences of 5 × 1016, 1 × 1017, and 5 × 1017 ions/cm2. X-ray diffraction, atomic force microscope, X-ray photoelectron spectroscopy (XPS), and UV–visible spectrophotometer are used to characterize the films. With increasing N ion fluences, the absorption edges of anatase TiO2 films shift to longer wavelengths and the absorbance increases in the visible light region. XPS results show that the red shift of TiO2 films is due to the formation of N–Ti–O compounds. As a result, photoactivity is enhanced with increasing N ion fluence.

ITO Thin Films on Silicon Buffer by Sol Gel Method

2006 ◽  
Vol 514-516 ◽  
pp. 1155-1160 ◽  
Author(s):  
Talaat Moussa Hammad
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Optical Transmission ◽  
Sol Gel ◽  
Precursor Solution ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ito Thin Films ◽  
Uv Visible

Sol gel indium tin oxide thin films (In: Sn = 90:10) were prepared by the sol-gel dipcoating process on silicon buffer substrate. The precursor solution was prepared by mixing SnCl2.2H2O and InCl3 dissolved in ethanol and acetic acid. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction. The surface morphology of the films was characterized by scanning electron microscope (SEM). Optical transmission and reflectance spectra of the films were analyzed by using a UV-visible spectrophotometer. The transport properties of majority charge carriers for these films were studied by Hall measurement. ITO thin film with electrical resistivity of 7.6 ×10-3 3.cm, Hall mobility of approximately 2 cm2(Vs)-1 and free carrier concentration of approximately 4.2 ×1020 cm-3 are obtained for films 100 nm thick films. The I-V curve measurement showed typical I-V characteristic behavior of sol gel ITO thin films.

Thermal stability and miscibility of co-evaporated methyl ammonium lead halide (MAPbX3, X = I, Br, Cl) thin films analysed by in situ X-ray diffraction

2018 ◽  
Vol 6 (24) ◽  
pp. 11496-11506 ◽  
Author(s):  
Paul Pistor ◽  
Thomas Burwig ◽  
Carlo Brzuska ◽  
Björn Weber ◽  
Wolfgang Fränzel
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Thermal Treatment ◽  
Phase Evolution ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray ◽  
Subsequent Thermal Treatment ◽  
Lead Halide

We present the identification of crystalline phases by in situ X-ray diffraction during growth and monitor the phase evolution during subsequent thermal treatment of CH3NH3PbX3 (X = I, Br, Cl) perovskite thin films.

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