Optical and Electrical Properties of Transition Metal Calcium Phosphate Glasses

Investigation was carried out between binary and ternary series in order to determine the role of transition metal (TM) ions in calcium phosphate glass. Various transition metal ions in calcium phosphate glass (TM0)y (Ca0)0.~(P~2-0~s) o.7(, TM = Cu, Mn and Zn) in the composition range 0.011x10.09 were prepared by traditional melt quenching technique. Optical absorption, dielectric spectroscopy, X-ray diffraction and Fourier Transform Infrared (FTIR) spectroscopy have been used to characterize the structural, optical and electrical features of the glasses. All of the samples under study have been confirmed to be amorphous by X-ray diffraction (XRD) measurements. Results from FTIR spectroscopy showed that the spectra were dominated by the spectral characteristic of P2O5 in a fingerprint region below 1500 cm". From the absorption edge studies, the values of optical band gap (EopJ and energy gap (E,) have been evaluated using Urbach absorbance rule. The values of optical band gap (Eop,) recorded for binary CaO-P205 glasses ranges from 3.578 to 2.1 14 eV while for ternary series CaO-P205 doped with Cu20, CuO, MnO and ZnO ranging from 2.1 14 to 1.697 eV, 3.310 to 1.718 eV, 3.030 to 3.279 and from 2.747 to 2.989 eV. Binary and ternary series doped with CU+ and ~ nsho~wed+ the energy gap, E, increased with metal oxide and dopant materials ranges from 0.500 to 1.564 eV, 0.681 to 0.736 eV and from 0.246 to 0.283 eV. CaO-P205 glasses doped with, cu2+ and zn2+ recorded inverse pattern where the values ranging from 1.863 to 0.600 eV and from 1.1 72 to 0.744 eV. Optical band gap (E,,,) and energy gap (E,) is suggested to be associated with structural disorder in the sample. A number of physical studies have also been conducted which include refractive index and density. The density of the glass was determined by Archimedes Principle. Refractive Index was determined at 589.3 nrn and 632.6 nrn and was found to agree with Lorentz-Lorenz equation where the refractive index increased with increase of density of the samples. Dielectric permittivity was measured in the temperature range of 25 to 300°C. Dielectric permittivity and dielectric loss factor for all samples decreased with frequency and increased with temperature between range 1 x 1 o3 to 1 Hz and from 1 x 10" to 1 x lop3 Hz. From the empirical data, other values such as molar volume and molar refractivity have been computed. Ionic refractivity, ionic radii and field strength have been interpreted from the obtained data. It is obvious that the refractive index varies with molar refractivity, which depends on the polarizability of the ions in the samples, density and molecular weight. Those properties were found to be sensitively depends on its compositions

Determination of thermal diffusivity polypyrrole and polypyrrole/bismuth oxide conducting polymers using laser flash technique

The determination of conducting polymer’s thermal properties is essential in engineering processes and design. Thermal diffusivity is one of the important thermal properties in non-steady state situations. This fundamental knowledge is useful in the development of processes and control, selection of materials and prediction of end use properties in many engineering process and design. In this research, laser flash technique is employed to determine the thermal diffusivity of Polypyrrole and Polypyrrole/Bismuth Oxide conducting polymers. Measurements were carried out from room temperature up to 420 K. It was observed that the presence of secondary doping agent of bismuth oxide enhanced the thermal properties of polypyrrole conducting polymer

Facile synthesis and characterizations of polypyrrole/BiOCl hybrid composites

Polypyrrole(PPy)/BiOCl hybrid composites were synthesized for the first time via one-step chemical oxidation process by addition of Bi2O3 nanoparticle in an aqueous solution of pyrrole monomer/FeCl3 oxidant agent. X-ray diffractions (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric technique confirmed the growth of BiOCl in PPy matrix. From the XRD, the amount of BiOCl in PPy matrix increased with increasing of Bi2O3addition in pyrrole solution. The FESEM images indicated the presence of two phases related to PPy and BiOCl. Thermal stability of PPy/BiOCl hybrid composites has been improved in the range 300–800 K and degraded above 800 °C, i.e., decomposition point of BiOCl. Fourier transforms infrared spectroscopy point to a mutual interaction between PPy and BiOCl system. The characteristic optical absorption peaks of PPy shifted to higher wavelength in PPy/BiOCl(5%) composites and disappeared at PPy/BiOCl(20%). From electrical measurement, the PPy/BiOCl hybrid composites have higher conductivity than PPy, where the maximum conductivity observed was for PPy/BiOCl(5%). The conducting mechanism of PPy and PPy/BiOCl composites followed three-dimensional Mott variable range hopping in the range of 300–150 K and has involved fluctuation-assisted tunneling phenomenon below 150 K

Perovskite solar cells with binary salt based gel polymer electrolyte

In this work, gel polymer electrolytes based poly(vinyl alcohol) (PVA) with different concentrations of tetrabutylammonium iodide (TBAI) and lithium iodide (LiI) salts have been prepared. The electrolyte conductivity at room temperature is observed to increase from 4.88 mS cm-1 for electrolyte with 17.02 wt.% PVA– 13.93 wt.% TBAI–0.96 wt.% I2–68.09 wt.% DMF (S1 electrolyte) to 6.47 mS cm-1 for electrolyte with 16.98 wt.% PVA–11.81 wt.% TBAI–2.09 wt.% LiI– 1.21 wt.% I2–67.92 wt.% DMF (S4 electrolyte). The conductivity increases from electrolyte S1 to S4 was attributed to the increase in the concentration of mobile ion. The increase in conductivity beyond the S4 electrolyte concentration is influenced by the mobility and diffusivity of charge carriers. All electrolytes prepared have been used in fabricating of methylammonium lead iodide (MAPbI3) perovskite solar cells. The perovskite solar cell with S4 electrolyte shows the highest power conversion efficiency of 1.75% with open circuit voltage (Voc) of 0.62 V and short circuit current density (Jsc) of 3.97 mA cm-2

Effect of zeolite on the thermal properties of conducting polymer Polypyrrole

This Polypyrrole and Polypyrrole/Zeolite conjugated system were successfully synthesized through the chemical oxidation polymerization method. The structural, morphological and thermal properties of the synthesized compound were characterized by Xray diffraction (XRD) analysis, Field Emission Scanning Electron Microscope (FESEM), Thermogravimetry Analysis (TGA) and Laser Flash Measurement. XRD confirmed the amorphous characteristic peak structure of Polypyrrole conjugated system at two theta ~25o . The incorporation of Zeolite resulted in the presence of sharp peak which implies that Polypyrrole/Zeolite conjugated system has some degree of crystallinity and more ordered arrangement than those Polypyrrole conjugated system. The FESEM morphology showed the formation of Polypyrrole and Polypyrrole/Zeolite conjugated system revealing a globular and coiled structure images. Thermal transport property of thermal diffusivity has been measured ranging from room temperature up to 420 K while thermal stability through thermo gravit metric analysis is measured from room temperature to 1273 K. The incorporation of Zeolite in conducting Polypyrrole shows an enhancement of thermal stability through laser flash measurement measurement and thermogravimetric analysis. As Zeolite content increases in the Polypyrrole/Zeolite samples, the conjugation length increased hence improved the thermal diffusivity and the thermal stability of the sample

Thermal activation of conducting polymer polypyrrole/zeolite

In this paper the influence of dopant on the electrical properties of polymer prepared by chemical oxidative polymerization method is investigated using the four point probe technique. Polymers are formed by using Pyrrole and Iron (III) Chloride Hexahydrate (FeCl3.6H2O) as well as Zeolite as dopant. The current-voltage was measured from 20 to 300 K. The current-voltage characteristic of all samples shows that the measured voltage increased linearly with current. It was found that conductivity increases with temperature and concentration of the dopant. As expected, the D.C. conductivity of Polypyrrole/Zeolite was found slightly higher than Polypyrrole which to be considered that Zeolite have altered and enhanced the conductivity of the samples. The increase in conductivity may be considered have to improved the thermal stability of the blends. An explanation is proposed based on the character and conduction mechanism of FeCl3/Polypyrrole/Zeolite

Preparation and physical properties of polypyrrole / zeolite composites

Polypyrrole (PPy′)/zeolite composites were synthesized via chemical oxidation of pyrrole in the presence of zeolite. FeCl3 was used as an oxidant with the FeCl3-to-pyrrole molar ratio (MR) equal to 1. The zeolite contents were 0%, 5%, 10%, 15% and 20% of the total weight of PPy′. For comparison, pure PPy″ with FeCl3–pyrrole MR equal to 2 was also synthesized using the same method. The structural and physical properties of the samples were studied using X-rays diffraction (XRD), Fourier transform infrared spectroscopy, field emission electron scanning microscopy, thermogravimetric analysis, van Der Pauw technique and UV–VIS-NIR spectroscopy. The XRD of PPy′/zeolite (5%) revealed a presence of crystalline nature of zeolite in a spectrum of host amorphous PPy′. The XRD peaks increased, became stronger and shifted slightly to higher 2θ in PPy′/zeolite (10–20%) composites. Compared with PPy′, the composites were denser, more compact and had better thermal stability. The composites conductivity increased while their bandgap tended to reduce with increasing of zeolite. PPy′/zeolite (20%) composite had the highest conductivity value of 3.6 S cm−1 with an optical bandgap of 2.21 eV. The results showed that zeolite has been incorporated into PPy′ matrix and improved its physical properties

Optical absorption spectrum of Cu2O-CaO-P2O5 glasses

Homogeneous CaO–P2O5 and Cu2O–CaO–P2O5 glasses were prepared using a melt-quenched method under controlled conditions. The binary glasses were found to be colourless and transparent while the ternary glasses changed from light green to dark green as the Cu2O content increased. From the absorption edge studies, the values of the optical band gap, Eopt and Urbach energy, ΔE were evaluated. The position of the absorption edge and hence the optical band gap were found to depend on the glass composition. Analysis of the optical band gap shows that for the binary glasses, the value increases as the content of CaO decreases, while for the ternary glasses, the value of the optical band gap increases as the content of the Cu2O decreases. The density of the glasses was also measured and was found to increase with the increase in CaO and Cu2O contents

Domestic electrical appliances consumption: the case of Centre of Foundation Studies for Agricultural Science UPM students

The electrical consumption for domestic applications in Peninsular Malaysia is investigated in this paper. The study is performed among the homes of Physics students at Centre of Foundation Studies for Agricultural Science, Universiti Putra Malaysia (UPM). The approximately 500 homes in Peninsular Malaysia are selected in this study, where the electricity in this region is governed by Tenaga Nasional Berhad (TNB). The purpose of this study is to recognize the electrical usage for the various types of household electrical appliances, together with their cost which contribute to the amount of electric bill. As a result, this study will be able to determine which household appliances consumes the most energy and cost. Thus, the paper also includes several practical ways to conserve electricity

Effects of zeolite and bismuth oxide addition on structural, thermal, optical, and electrical behaviour of conducting polymer polypyrrole

Polypyrrole (PPY), Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide powders were successfully synthesized through the chemical oxidation polymerization method containing pyrrole monomer, iron (III) chloride hexahydrate as primary doping agent and Zeolite and Bismuth oxide as secondary doping agents. The Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide conjugated systems prepared at different concentration percentages ranging from 0 % to 20 %. The structural, compositional, morphological, thermal, optical, magnetic and electrical properties of the synthesized compound were characterized by X-ray diffraction (XRD) analysis, Energy Dispersion X-Ray Fluorescence (ED-XRF), Fourier Transform Infrared (FTIR), Field Emission Scanning Elelctron Microscope (FESEM), Thermogravimetry Analysis (TGA), Electron Spin Resonance (ESR), Laser Flash measurement, Diffuse Reflectance Spectroscopy (DRS) and Van Der Pauw (VDP) technique. XRD confirmed the amorphous characteristic peak structure of pristine Polypyrrole at two theta ~25o. The impregnation of Zeolite and Bismuth oxide resulted in the presence of sharp peak which implies that both Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide has some degree of crystallinity and more ordered arrangement than those pristine of Polypyrrole conjugated system. The elemental analysis confirmed the presence of primary and secondary doping agents in all Polypyrrole conjugated systems and witnessed the increment of every element as it were increased. This is in agreement with FTIR analysis which revealed the successful incorporation of primary and secondary doping agents in Polypyrrole conjugated systems through its nearly identical and positions of IR absorption bands of Polypyrrole, Zeolite and Bismuth oxide to which is available in literature. The FESEM morphology showed the formation of Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide revealing a globular images or cauliflower morphology of Polypyrrole. It also revealed that all the agents of primary and secondary doping have complete miscibility with Pyrrole forming a Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide.Thermal stability is mainly studied by TGA. It was observed that the impregnation of Zeolite and Bismuth oxide in the conjugated system have shown a remarkable improvement on thermal stability of Polypyrrole conjugated systems which suggested that the structure formed is well orderly structured and strong. The ability of Polypyrrole, Polypyrrole/Zeolite and Polpyrrole/Bismuth oxide conjugated systems to transit heat was measured using Flash technique. Higher molecular weight and higher crystallinity resulted from Zeolite and Bismuth oxide are believed to increase the conjugation length and providing more through-space pathways for electron to migrate and thus increased the thermal diffusivity. Three peaks of absorbance are observed for Polypyrrole, Polyprrole/Zeolite and Polypyrrole/Bismuth oxide at different photon energy which are believed to be associated with transitions from below band edge to bonding and anti-bonding levels of polarons (band gap), bonding to anti-bonding levels of polarons (intraband), and valence band to conduction band (interband). Estimation of energy gap using Kabelka-Munk treatment revealed that the incorporation of secondary doping agents of Zeolite and Bismuth oxide changed the energy gap to a smaller range value. Presence of polaron in all samples was confirmed by ESR spectroscopy technique. The spin number (Ns) was determined and found to depend on primary and secondary doping agent concentrations level in Polypyrrole conjugated system. ESR linewidth showed temperature dependence and suggests the validity of the Elliot relaxation for Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide conjugated system. The electrical conductivity studies were investigated using Van Der Pauw technique at temperature range between 20 K until 300 K. From the results, it was observed that the electrical conductivity increased with increasing of primary and secondary doping agents in Polypyrrole conjugated systems. It was found that the electrical conductivity of pristine Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide conjugated systems strongly depends on the applied temperature. There were two regimes of electrical conductivity observed where the first regime is from 20 K to 50 K and the second regime starts from 50 K up to 300 K. Temperature dependence of conductivity of pristine Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide conjugated systems samples between temperatures of 50 K until 300 K suggests a transition from semiconducting nature to metallic nature. In the temperature range from 50 K to 300 K range, the charge carrier mechanism was dominated by 3-D variable range hopping mechanism, VRH transport