Markus Diantoro

Synthesis of silver nanoparticles by chemical reduction at various fraction of MSA and their structure characterization

Nanosilver is currently one of the most common engineered nanomaterials and is used in many applications that lead to the release of silver nanoparticles and silver ions into aqueous systems. Nanosilver also possesses enhanced antimicrobial activity and bioavailability that may less environmental risk compared with other manufactured nanomaterials. Described in this research are the synthesis of silver nanoparticle produced by chemical reduction from silver nitrate (AgNO3) solution. As a reducing agent, Sodium Borohydride (NaBH4) was used and mercaptosuccinic Acid (MSA) as stabilizer to prevent the nanoparticle from aglomerating. It was also used two kinds of solvent, they are water and methanol. In typical experiment MSA was dissolve in methanol with a number of variation of molarity i.e. 0,03 M, 0,06 M, 0,12 M, 0,15 M, and the mixture was kept under vigorous stirring in an ice bath. A solution of silver nitrate of 340 mg in 6,792 ml water was added. A freshly prepared aqueous solution of sodium borohydr...

The influence of iron- and copper- doped of PANi thin film on their structure and dielectric properties

Polyaniline (PANi) is one of conductive polymers which are widely studied. PANi has unique in the structure and physical properties that can be controlled by doping. In this work we report the role of CuCl2 and FeCl3 in the crystalline and dielectric properties of PANi/Ag films which was performed by means spin coating method. We employed sonochemical technic to form solutions of PANi ES II prior to spin coating method. The variation of FeCl3 and CuCl2 doped were used in the range of 0 M - 0.5 M. FTIR spectra of PANi EB and PANi ES clarified that the PANis were successfully synthesized. The crystallinity of the films were examined by menas of X-ray diffraction (XRD). While the polymeric grains were evaluated using SEM which is confirmed with the grain size analyses from X-RD data. Dielectric properties shows that introducing Fe and Cu doped could decrease their dielectric constant. The decreasing of dielectric constant was also achieved by increasing frequency.

Shockley’s Equation Fit Analyses for Solar Cell Parameters from I-V Curves

Some of the technical problems that appear are obtaining solar cell parameters from I-V curve measurement data. One simple method is using linear graphical fit at zero current or voltage conditions. Although the accuracy of the obtained values is acceptable, other problems may arise regarding the number of parameters which could be obtained. We report a comparison between manual or graphical fit and fit using Shockley’s equation. The single I-V curve under the lighting was inferred to obtain the intrinsic parameters of the solar cells’ performance. The fittings were performed using the nonlinear equation of Shockley by determining some initial values of fittings such as Rs, Rsh, n, I0, Iph, and T. In the case of the Shockley equation fit, the iteration was performed several times to obtain the least possible inferred parameters. We have successfully obtained a better result of nonlinear Shockley fitting compared to the manual linear fit.

Microstructure and dielectric properties of cellulose acetate-ZnO/ITO composite films based on water hyacinth

The electrical properties of Cellulose Acetate (CA), especially extracted from water hyacinth, is rarely informed. CA is generally more stable compared to its cellulose. It has a good potential for electronic application with specific modifications such as inducing metal oxide. A combination of intrinsic properties of Zinc Oxide (ZnO) and CA is expected as a great potential for electrical and optical applications. CA-ZnO/ITO composite film was investigated in relation with its structure, dielectric constant, and the effect of light intensity on their dielectric constant. CA-ZnO composite films were prepared with different mass of ZnO i.e. 0; 0,02; 0,04; 0,06 and 0,08 grams. CA-ZnO solution was synthesized via the mixing method with PEG:DMF solvents by using a magnetic hotplate stirrer with the rotation rate of 1500 rpm at 80°C. The CA-ZnO solution was then deposited onto ITO/glass substrate by using spin coating technique. The CA-ZnO/ITO films were annealed at 160°C to remove the remaining solvents. The effects of ZnO composition on the structure (crystallinity and morphology) and dielectric constant properties were investigated by using X-Ray Diffractometer, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and LCR meter. It was shown that cellulose can be isolated from water hyacinth with the yield of 67,72 % by Chesson method and can further be transformed into CA. The X-ray diffraction pattern showed that there are 2 phases formed i.e. CA and ZnO. Furthermore, greater ZnO amount increased the crystallinity of composite films. The CA-ZnO films exhibit porous films with ZnO distributed on the CA surface films. Therefore, ZnO increases the dielectric constant of CA-ZnO composite films.

The Role of Fe2O3 and Light Induced on Dielectric Properties of Borosilicate Glass

Functionally glass materials have been widely applied in various technological applications remarkably due to their optoelectric properties. In this present study, the glass was prepared from leaching product of local silica sands. Bi2O3 and Na2CO3 were added to reduce the melting point of silica sand to form silica glass and Fe2O3/B2O3 was incorporated to examine its effect on the crystal structure, morphology, and light-induced dielectric properties of the borosilicate-based fuctional glass. The characterizations were conducted by means of Differential Thermal Analyses (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and capacitance meter under the influence of light intensity. The XRD pattern shows the absence of any sharp diffraction peak indicates the amorphous state of the borosilicate glass. While the SEM image shows that the borosilicate glass exhibited amorphous characteristic. Furthermore, the increasing of Fe2O3 tends to reduce the dielectric constant. On the other hand, the increase of light intensity increase the dielectric constant with a step like properties.

Effect of NiO and Light Intensity on Dielectric Constant of SiO2-B2O3-Bi2O3-Na2CO3 Glass Based on Silica Gel of Natural Sands

The use of silica in various fields is significantly increasing. One common application is silica based functional glass which has naturally show specific dielectric, optical, and magnetic properties. Many studies have been performing to explore the influence of dopant, composition, and other processing parameters as well as employing various characterization. In the previous work, we report the use of silica from silica sands. To reduce the melting temperature, we used silica sol-gel beside the utilization of some oxides such as B2O3, Na2CO3, and Bi3O3. We also used NiO as dopant explore the glass properties. We have prepared a series of sample with the composition of 50SiO2-25B2O3-(6.5-x) Bi3O3-18.5 Na2CO3-xNiO (x = 0, 1, 2, 3 and 4 wt%). After weighting process, the composition was blended, then heated to 450 °C for 120 minutes and then raised at 950 °C for 60 minutes in the crucible. Then samples of glass separated from the crucible and in the characterization of the structure using the DTA, XRD, SEM-EDAX and FTIR and measuring dielectric constant using a capacitance meter. The increase of NiO dopant resulted in increasing the dielectric constant of glass. On the other hand, the dielectric constant gradually decreases with the increase of light intensity. One can be noted that the applied intensity give rise to the step-like decrease of the dielectric constant. Whereas, the increasing magnetic field indicate the increase of dielectric constant.

Synthesis, Investigation on Structural and Magnetic Behaviors of Spinel M-Ferrite [M = Fe; Zn; Mn] Nanoparticles from Iron Sand

Spinel M-ferrite [M = Fe; Zn; Mn] nanoparticles were prepared from iron sand using a coprecipitation-sonochemical approach. The purified Fe3O4 from iron sand, ZnCl2 and MnCl2.4H2O, HCl, and NH4OH were used as raw materials. X-Ray Diffractometer (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), and Vibration Sample Magnetometer (VSM) were employed to characterize the crystal structure, functional groups, particle size, morphology, and magnetic behavior of the prepared samples, respectively. From the XRD data analysis, M-ferrite particles exhibited a single phase in spinel structure. Furthermore, the M-ferrite particle increased their lattice parameter and crystal volume tracking the metallic-ionic radii of M. The particle size of the M-ferrites particles varied with M, whereas the biggest and lowest were for Zn and Mn, respectively. Based on the magnetization curve, the M-ferrite nanoparticles tended to perform a superparamagnetic behavior and their saturation magnetization as a function of their M ion and particle size.

Crystallinity and Electrical Conductivity of PANI-Ag/Ni Film: The Role of Ultrasonic and Silver Doped

Polyaniline (PANI) is typically a conductive polymer which has a uniqueness in structure and physical properties. The physical properties generally can be controlled by introducing a specific dopant as well as other processing parameters. This polymer has been widely investigated and applied in various fields, especially in electronics. Some metallic elements have been introduced to modified its characteristic such as iron and copper. In order to improve the characteristic of this material, it is important to study the optimum process as well as the elemental substitution of PANI films. In this study, we report the influence of employing sonochemistry technic and the silver substitution on the crystallinity and electrical conductivity of PANI/Ni films. The samples have been prepared similarly to the previous report with silver doped in the range of 0.1 ≤ x ≤ 0.5 M. Other series of the sample were also prepared at various irradiation time of ultrasonic exposure. FTIR spectra showed that EB and ES Polyanilines had been successfully synthesized. X-RD histogram also revealed that crystallinity of the films comparably increased with the increase ultrasonic irradiation time as well as the silver in dopant. Along with the crystallinity, the electrical conductivity of films also increased as an increase of the dopant and of ultrasonic irradiation time.

Preparation of Superparamagnetic Zn0.5Mn0.5Fe2O4 Particle by Coprecipitation-Sonochemical Method for Radar Absorbing Material

One of many applications of spinel ferrite nanoparticles is related to their performance as radar absorbing materials. In this work, we report developing synthesis method through combined coprecipitation-sonochemical routes in preparing Zn0.5Mn0.5Fe2O4 nanoparticle from iron sand in Indonesia as a vital raw material. The structure, size, morphology, and elements of the Zn0.5Mn0.5Fe2O4 nanoparticle were investigated via X-Ray diffractometry and Transmission/Scanning Electron Microscopy (TEM/SEM) combining Energy Dispersive Spectroscopy (EDS). The magnetic properties of the Zn0.5Mn0.5Fe2O4 nanoparticle were characterized by using Vibrating Sample Magnetometer (VSM). Furthermore, the reflection loss character of the Zn0.5Mn0.5Fe2O4 nanoparticle was determined via Vector Network Analyzer (VNA). From the qualitative and quantitative analysis of the XRD data, it can be identified that the Zn0.5Mn0.5Fe2O4 particle formed a spinel cubic structure in a single phase with the lattice parameter of approximately 8.401 A. It is known from the TEM image that the Zn0.5Mn0.5Fe2O4 particle had a size of about 9.7 nm and tended to agglomerate. Furthermore, the data analysis of the M(H) curve presented that the Zn0.5Mn0.5Fe2O4 nanoparticle has a superparamagnetic behavior with the saturation magnetization of approximately 43 emu/g. Finally, the data analysis of the reflection loss as a function of frequency showed that the Zn0.5Mn0.5Fe2O4 nanoparticle performs as a radar absorbing material with the absorption performance of approximately -11.0 dB at the frequency of 10.8 GHz

Fabrication of Magnetite Nanoparticles Dispersed in Olive Oil and Their Structural and Magnetic Investigations

In this work, the iron sand taken from Wedi Ireng Beach in Banyuwangi, Indonesia, was employed as the main precursor in fabricating magnetite nanoparticles. The magnetite nanoparticles were then functionalized in preparing magnetic fluids coated by oleic acid as a surfactant and dispersed in olive oil as a liquid carrier. The phase purity, crystallite size and crystal structure of the dried magnetic fluids were characterized by using X-Ray Diffractometer. Meanwhile, the functional groups of the magnetic fluids were investigated by means of Fourier Transform Infra-Red (FTIR) spectroscopy. The particle size and morphology of the magnetite particles were also investigated by using Transmission Electron Microscopy (TEM). The magnetic behaviors of the magnetic fluids were determined by using Vibrating Sample Magnetometer (VSM). Based on the XRD data analysis, the magnetite particles crystallized in the spinel structure without the presence of any other phases. The FTIR spectra showed that the functional groups of the magnetic fluids were referring to the magnetite, oleic acid, and olive oil. The TEM image presented that the magnetite particle was formed in a nanometric size. Finally, the saturation magnetization of the magnetic fluids varied in the mass composition and particle size of the magnetite nanoparticles.