Effect of applied voltage to the characteristic of TiO2 nanofibers fabricated using electrospinning techniqueSafriani, L; Ardiansyah, M I; Faizal, F
doi: 10.1088/1742-6596/2376/1/012014pmid: N/A
Titanium dioxide (TiO2) is an attractive semiconductor oxide compound due to its good stability properties both in chemical and photochemical. TiO2 in the form of nanofibers offers many advantages such as high surface area, flexibility of structures and mechanical properties such as stiffness and tensile strength. In this study, we reported the synthesis of TiO2 nanofibers using electrospinning technique. TiO2 nanofibers were produced from titanium (IV) iso-propoxide precursor solution at different applied voltages of 10 kV and 12 kV, while the flowrate was kept constant at 0.7 ml/hours during the process. The electrospinning process produced a thin layer of nanofibers which was then calcined for 1 hour at different calcination temperature. Based on the SEM images, we found that at applied voltage of 12 kV uniform and continuous nanofibers had already formed with the average diameter of nanofibers was in the order of sub microns. The diffraction pattern of TiO2 nanofibers shows that at a calcination temperature of 450°C, the phase was dominated by the anatase phase, while at 500°C it has a combination of anatase and rutile phases. Based on UV-Vis spectroscopy, it was found that the energy gap of TiO2 nanofibers calcined at temperature of 450°C and 500°C were 3.32 eV and 3.22 eV, respectively.
Effect of Fe Magnetic Impurity to the Crystal Structure and Magnetic Properties of Eu 1.83+y Ce 0.17−y Cu 1−y Fe y O 4+α−δAnggia, H D; Rochman, L P; Pratama, R; Maryati, Y; Syakuur, M A; Widyaiswari, U; Sari, D P; Saragi, T; Risdiana,
doi: 10.1088/1742-6596/2376/1/012008pmid: N/A
In the overdoped regime of superconductors, both electron- and hole-doped superconductors exhibit intriguing phenomena like the Quantum Critical Point. Other phenomena, such as cooper-pair breaking and stripe pinning, can be observed by eliminating superconductivity by the addition of impurities. In this study, we investigate the crystal structure and magnetic properties of electron-doped superconducting cuprates of Eu2-x+yCex-yCui1-yFeyO4+α-δin the overdoped regime of x = 0.17 for Ce doping with y = 0.005, 0.01 and 0.03 for Fe impurity. The material has a tetragonal T’ structure that matches the ECCO crystal structure, according to the XRD analysis of the crystal structure. The addition of magnetic impurity has no effect on the structure but does decrease the lattice parameter. SQUID was used to measure the magnetic susceptibility at low temperatures between 2 K and 30 K. The spin-glass was observed at y = 0.03, due to the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction as shown in a hole-doped system. Due to the significant contribution from the magnetic moment of the Fe ion, the addition of Fe concentrations increases the effective magnetic moment. The conduction layer’s spin correlation of Cu is dramatically disrupted by the addition of Fe, resulting in the breakage of the copper-pair and the elimination of superconductivity.
Preparation of TiO2/ZrO2 Composite as Photoanode of Ruthenium-Based Dye-Sensitized Solar CellsKusdiana, Rochmat Fadillah; Aprilia, Annisa; Safriani, Lusi
doi: 10.1088/1742-6596/2376/1/012007pmid: N/A
Photoanode of dye-sensitized solar cell (DSSC) is an inorganic semiconductor layer with a nanoporous structure that has a function as a charge carrier transport layer and dye storage. Oxide semiconductor material such as titanium dioxide (TiO2) is widely used as a photoanode because of its wide band gap (3.2 eV) and high active surface area (80 m2/g), but TiO2 has low electron diffusion with high recombination (electron-hole pair pairing). To improve the electron diffusion and reduce recombination, TiO2 was modified with zirconia (ZrO2). The synthesis process was carried out using sol-gel method with variations of ZrO2 concentrations at 5 mol%, 10 mol%, and 15 mol%. Composite of TiO2/ZrO2 was then applied as a photoanode of DSSC. XRF results show that in all variations of ZrO2, the composites of TiO2/ZrO2 has been formed. Based on the results of UV-Vis spectroscopy, it was shown that the energy gap of TiO2/ZrO2 decreased as the increasing of ZrO2 concentration. The current density-voltage measurement was done to investigate the effect of ZrO2 addition to the TiO2 photoanode using light irradiation with power intensity of 100 mW/cm2. There is an increasing of photocurrent from 1.63 mA/cm2 of DSSC with TiO2 photoanode to 2.79 mA/cm2 of DSSC with TiO2/ZrO2 10 mol% photoanode. The highest efficiency obtained from DSSC with TiO2/ZrO2 photoanode is 1.15%. It was found that the presence of ZrO2 in the composite of TiO2/ZrO2 increased electron transport and reduced charge recombination to improve the photocurrent of DSSC.
Single Crystal Perovskite MAPbBr3 Prepared by Using Anti-solvent Vapor-assisted Crystallization MethodMuslimawati, R M; Manawan, M; Takahashi, K; Furukawa, Y; Bahtiar, A
doi: 10.1088/1742-6596/2376/1/012005pmid: N/A
Perovskite methylammonium lead tri-bromide (MAPbBr3) material has gained a lot of attention in the past few years due to its impressive optoelectronic properties, which is suitable for high efficiency and sensitivity X-ray photodetector. Compared to polycrystalline crystal structure, MAPbBr3 single crystal is more ideal for X-ray photodetector because lack of grain boundary therefore produce more sensitive photodetector. However, a cubic structure and large crystal dimension is highly required to adjust into the flat-panel detector configuration. In this research, MAPbBr3 perovskite crystals were synthesized by using Anti-solvent Vapor-assisted Crystallization (AVC) at room temperature using dimethylformamide (DMF) as solvent and Dichloromethane (DCM) as antisolvent. The precursors for the MAPbBr3 solution were prepared by varying the molar ratio of MABr:PbBr2 as precursor solution. The crystal growth rate was controlled by varying the volume ratio of DCM and MAPbBr3 precursor solution. The obtained largest crystal size of 10 mm × 10 mm was prepared with a volume ratio of DCM and precursor is 3 and a volume of precursor solution is 6 ml. The XRD of large cubic MAPbBr3 crystal showed a peak of (100) plane, which indicates a single crystal oriented in a-axis direction. The Raman spectra peaks of perovskite MAPbBr3 crystals showed organic (MA+) and inorganic (PbBr2−) bonds in a cubic phase of single crystal MAPbBr3. All samples that were prepared with different ratios of DCM and precursor solution have the same Raman spectra, which confirm that all MAPbBr3 crystals have cubic crystal structure.
Effect of Protonation Doping of Polyaniline Electrodes using Hydrochloric Acid on Its Pseudocapacitor CapacitanceFitriantika, L A; Fitrilawati, ; Syakir, N
doi: 10.1088/1742-6596/2376/1/012006pmid: N/A
Pseudocapacitor is a supercapacitor that can store charge faradically through a reversible redox reaction. Polyaniline (PANi) is one of the promising active materials for pseudocapacitor electrodes since it can produce theoretical specific capacitance up to 750 F/g. We prepared leucomeraldine base polyaniline (LB-PANi) electrodes by deposition of dissolved LB-PANi powder in N,N-Dimethylformamide (DMF) using spraycoating technique. The LB-PANi electrodes was then doped with 1 M HCl through protonation process to obtain emeraldine salt polyaniline (ES-PANi) electrodes. We used both electrode materials and 1 M KCl to prepare a symmetrical sandwich supercapacitor model of <LB-PANi|KCl|LB-PANi> and <ES-PANi|KCl|ES-PANi>, as well as measured their performance. The results show a significant increase of the specific capacitance of PANi supercapacitor from 15.02 F/kg to 1876.87 F/kg when the electrodes of the LB-PANi were changed with the ES-PANi electrodes.
Eggshell-Graphene Oxide Layer as Membrane Filtration for Removal Methylene Blue in Waste WaterMaulida, G; Fauziah, Y; Syakir, N; Fitrilawati,
doi: 10.1088/1742-6596/2376/1/012002pmid: N/A
Eggshell (ES) membrane is a semipermeable membrane that is insoluble in water and has a high surface area. We modified ES membranes with graphene oxide (GO) using self-assembled technique and used it to remove dye pollutants such as methylene blue (MB) in water. The ES membranes were obtained from fresh eggs that have been removed from albumen and yolk, then immersed in 15% acetic acid for 30 minutes. The ES membranes were immersed in 0.5 mg/mL dispersed GO and ultrasonicated for 3 hours. The modified ES-GO membrane was then used to filter 5 mg/L MB solutions. Filtration of MB solution was performed by pouring the solution over the ES-GO membrane with a help of constant pressure of 45 psi. We found that the modified ES-GO membrane could filter MB up to 33.53% and reduce MB concentration from 4.91 mg/L to 3.53 mg/L. The result of membrane permeability is 2.488 x10−3 darcy and the flow rate of the filtration is relatively constant about 4 mL/s.
The Analysis of Triaxial Passive Seismic Signal Data Using Python Scripting LanguageFazriati, Evi; Bahri, Ayi Syaeful; Rosandi, Yudi
doi: 10.1088/1742-6596/2376/1/012015pmid: N/A
The local geological and the physical conditions of earth’s ground defines its vibration characteristics. Such vibrations can be detected using conventional passive seismic methods, i.e., a microtremor recording method, which acquires ground vibration data in a suitable sampling time. The method utilizes natural seismic sources, originating from both natural and artificial sources. In this work we present the algorithm to process passive seismic signals, recorded from a laboratory developed triaxial seismic logging device. We use python scripting language to perform the signal processing work. We analyzed the Horizontal to Vertical Spectral Ratio (HVSR) of the signal to determine the on-site natural frequency. The results were compared to the reference data from a high sensitivity microtremor apparatus, at the exact same location. The results show a fair agreement between the low sensitivity and the high sensitivity seismometer, on the sites with low environmental disturbance. However, the values fluctuate significantly at noisy sites. Either way, our results measure the correct dominant frequencies as expected from the geological condition.
Peer Review Statementdoi: 10.1088/1742-6596/2376/1/011002pmid: N/A
All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing Publishing.• Type of peer review: Single Anonymous• Conference submission management system: Morressier• Number of submissions received: 22• Number of submissions sent for review: 20• Number of submissions accepted: 18• Acceptance Rate (Submissions Accepted / Submissions Received × 100): 81.8• Average number of reviews per paper: 2.0555555555555554• Total number of reviewers involved: 12• Contact person for queries:Name: Budi AdiperdanaEmail: [email protected]: Padjadjaran University - Physics
Photoactivity Enhancement of TiO2 Nanoparticle-decorated ZnO as a Photocatalyst in Methylene Blue DegradationRamadhika, L N; Suryaningsih, S; Aprilia, A
doi: 10.1088/1742-6596/2376/1/012003pmid: N/A
Zinc Oxide (ZnO) and Titanium Dioxide (TiO2) are metal oxides that are commonly used as photocatalysts material due to photoactivity characteristics. ZnO has a better reduction potential, and high electron mobility, but has a lower contact surface area than TiO2. On the other side, TiO2 has a better photoactivity to degrade pollutants referring to high surface area but has lower electron mobility compared to that ZnO. The combination of these two metal oxides is estimated can produce a better photocatalytic activity due to the advantages of each characteristic. Therefore, in this research, the ZnO-TiO2 (1:1) was prepared and investigated. ZnO nanoparticle was synthesized by the sol-gel method using zinc acetate dihydrate as a precursor, before calcining process, anatase TiO2 powder was added to form the composite. Structural, morphological, and optical characteristics of composite powders were analyzed by using XRD, TEM, UV-Vis Spectroscopy, and PL Spectroscopy. The concentration degradation of methylene blue in a solution containing composite material was observed to determine the photocatalytic activity under UV light irradiation for 30 minutes. The XRD spectrum shows the anatase phase of TiO2 and hexagonal wurtzite of ZnO crystal structure. Based on TEM imaging ZnO nanoparticles were attaching to TiO2 surfaces estimated due to van der walls bond. The ZnO/TiO2 shows a better photoactivity up to 20 minutes reaction with a higher degradation constant rate that indicates faster methylene blue degradation.