Structural, absorption and optical dispersion characteristics of rhodamine B thin films prepared by drop casting technique

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Physics of amorphous materials by S. R. Elliott

DC conductivity and study of AC electrical conduction mechanisms by non-overlapping small polaron tunneling model in LiFeP2O7 ceramic

The sensing properties of various metallophthalocyanines layered on Quartz Crystal Microbalance (QCM) transducers towards toluene vapor were investigated. Structural and morphological properties of thermally evaporated thin films of substituted and unsubstituted phthalocyanines were firstly characterized by Infrared spectroscopy, X-ray Diffraction and Scanning Electron Microscopy. The sensing characteristics were then determined from QCM responses to toluene at room temperature and correlated to physical and chemical properties of thin films. Effects of molecular composition of phthalocyanine, especially the nature of metal atom in the central cavity and peripheral grafted substituents, on sensor metrological characteristics were established. No significant effect because of change of the central metal atom (Cu, Zn, Fe, Co) in monomeric phthalocyanines was observed on toluene sensitivity. In contrast, strong effects of substituents particularly tert-butyl group at the periphery of the phthalocyanine ring on sensor response were highlighted. The sensing behavior of metallophthalocyanines towards toluene has been interpreted in correlation with the chemical nature of the materials (nature of metal atom and peripheral grafting groups), the physical properties of the sensitive films (structure, morphology and thickness) and the involved molecular interactions forces.

Phthalocyanines based QCM sensors for aromatic hydrocarbons monitoring: Role of metal atoms and substituents on response to toluene

http://staff.du.edu.eg/upfilestaff/222/researches/3222_1433586428__1-s2.0-S138614251.pdf

Influence of gamma ray irradiation and annealing temperature on the optical constants and spectral dispersion parameters of metal-free and zinc tetraphenylporphyrin thin films: A comparative study.

Thin films of CoPc of various thickness have been deposited onto glass substrates using thermal evaporation technique at room temperature. The dark electrical resistivity measurements were carried out at different temperature range (298–423 K). An estimation of mean free path () of charge carriers in CoPc thin films and bulk resistivity, was attempted. Measurements of thermoelectric power confirm that CoPc thin films behave as p -type semiconductors. The ac conductivity ( σ ac ) has been investigated in the frequency range (10 2 –10 6  Hz) and temperature range (298–407 K). σ ac is found to be proportional to ω s where s ≈ 0.879 which is frequency and temperature independence. The ac conductivity interpreted by the correlated barrier hopping (CBH) model with centers of intimate valence alternation pairs type with a maximum barrier height, W M ≈ 1.594 eV.

Structural and electrical properties of thermally evaporated cobalt phthalocyanine (CoPc) thin films

https://www.kau.edu.sa/Files/130/Researches/50778_23373.pdf

Effects of γ-irradiation and heat treatment on structural, spectral and optical parameters of pyronine G(Y) thin films

Cadmium thiogallate CdGa2S4 thin films were prepared using a conventional thermal evaporation technique. The dark electrical resistivity calculations were carried out at different elevated temperatures in the range 303–423 K and in thickness range 235–457 nm. The ac conductivity and dielectric properties of CdGa2S4 film with thickness 457 nm has been studied as a function of temperature in the range from 303 to 383 K and in frequency range from 174 Hz to 1.4 MHz. The experimental results indicate that σac(ω) is proportional to ωs and s ranges from 0.674 to 0.804. It was found that s increases by increasing temperature. The results obtained are discussed in terms of the non overlapping small polaron tunneling model. The dielectric constant (e′) and dielectric loss (e″) were found to be decreased by increasing frequency and increased by increasing temperature. The maximum barrier height (Wm) was estimated from the analysis of the dielectric loss (e″) according to Giuntini’s equation. Its value for the as-deposited films was found to be 0.294 eV.

Electrical conductivity and dielectric properties of cadmium thiogallate CdGa2S4 thin films

The dark current–voltage characteristics of p-S x Se 100− x /n-Si heterojunctions, with x  = 0, 2.5, 5.8 and 7.28 at.% S have been investigated in a temperature range from 303 to 383 K. The operating conduction mechanisms were found to be the thermionic-assisted tunnelling and pure tunnelling for low and high forward bias, respectively. Under reverse biasing, the operating conduction mechanism is the generation recombination mechanism. Analysis of the photovoltaic characteristics at room temperature and under illumination of ∼477 Wm −2 leads to the determination of some solar cell parameters, such as, the short circuit current density ( J SC  ≈ 165, 140, 116.7 and 103.3 A/m 2 ), the open-circuit voltage ( V oc  ≈ 0.36, 0.35, 0.32 and 0.31 V), the fill factor (FF ≈ 0.344, 0.372, 0.360 and 0.378) and the power conversion efficiency ( η  ≈ 4.278, 3.816, 2.814 and 2.534%) for x  = 0, 2.5, 5.8 and 7.28 at. % S, respectively.

A. M. A. El-Barry

Papers

Structural and electrical properties of thermally evaporated cobalt phthalocyanine (CoPc) thin films

Effects of γ-irradiation and heat treatment on structural, spectral and optical parameters of pyronine G(Y) thin films

Electrical conductivity and dielectric properties of cadmium thiogallate CdGa2S4 thin films

Transport mechanisms and photovoltaic characteristics of p-SxSe100-x/n-Si heterojunctions

Studies on structural and optical properties of thermally evaporated nanocrystalline thin films of meso-Tetraphenylporphyrin manganese(III) chloride