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61	Instrumentation, Acoustics, and Signal Processing	ABS-167
Real time monitoring system for thermocouple inhomogeneity equipment Heri Nugraha (a*), Agung Imaduddin (a), Aditya Achmadi (b), Suryadi (c), Agus Sukarto Wismogroho (c) a) Pusat Penelitian Metalurgi dan Material, LIPI Gedung 470, Kawasan Puspiptek, Serpong, Banten, Indonesia *heri014[at]lipi.go.id b) Badan Standardisasi Nasional Kawasan Puspiptek, Serpong, Banten, Indonesia c) Pusat Penelitian Fisika, LIPI Gedung 442, Kawasan Puspiptek, Serpong, Banten, Indonesia Abstract Thermocouple inhomogeneity equipment was developed to measure the seebeck coefficient characteristic in each wire position based on the effect of temperature exposure along the thermocouple wire. Temperature and distance sensors are used to measure the temperature output of the heating system and the movement of the thermocouple position. We developed a real time measurement system to monitor the measurement of the thermocouple sensor based on a microcontroller. The program was compile and upload to ESP 32 then monitoring data with an open source internet of things called Thingspeak is used as a platform to retrieve and display the collected data. Real-time monitoring of distance from ultrasonik and temperature of heat source (heat gun) can be accessed through web applications and smartphones. The data is analyzed real time and base on conditions. This study has been considered successfully implemented that performs on IoT platforms and adaptively ready to monitor thermocouple inhomogeneity equipment. Keywords: Microcontroller, Monitoring System, Thermocouple wire, Inhomogeneity Share Link | Plain Format | Corresponding Author (Heri Nugraha)

62	Interdisciplinary Physics	ABS-107
Maintaining Favorable Fermentation Conditions in Sargassum Liquid Fertilizer Production Using Siphon in A Two-Containers System Resulting in Acceptable Levels of Heavy Metals Nurhayati (a*), Anjar Purba Asmara (b), Sparisoma Viridi (c), and Feizia Huslina (a) a) Biology Department, UIN Ar-Raniry Jl. Syekh Abdur Rauf, Kopelma Darussalam, Banda Aceh, Indonesia *nurhayati.sururi[at]ar-raniry.ac.id b) Chemistry Department, UIN Ar-Raniry Jl. Syekh Abdur Rauf, Kopelma Darussalam, Banda Aceh, Indonesia c) Physics Department, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia Abstract Siphon in the form of simple u-shape was used to connect to two 600 ml disposed plastic bottles of mineral water called container A and B. Container A served as decomposter drum, while B was an aeration drum. In the decomposter drum, Sargassum porridge mixed with EM4 (effective microorganisms 4), organic nutrients, and water was placed allowing an anaerobic fermentation to occur within 25 days. In the aeration drum, we put an acceptable volume of fresh water. Between these two containers, the siphon was set to connect the air in each container above the suspension. There were 14 different configurations including siphon with three different diameters (0.5, 1, 1.5 cm), four different lengths (16, 18, 20, 22 cm), and three different connection (connected to aeration drum, opened to air, closed). The last two configurations did not need the siphon. During the fermentation process, gas and heat were perceptibly released from the suspension in the decomposter drum. Produced gas was flowing to the connect nearby drum and creating bubble whereas the air from the other drum was unable to enter the first drum leading to maintainance of the condition of fermentation process. After 25 days, the mixture was filtered. As the one of main challenging aspects in production sargassum liquid fertilizer is the considerable numbers of heavy metals, therefore, we measured the some heavy and transition metals level extracted in the lyes from 14 configurations to estimate the safety level of the product compared to those mentioned in the Regulation of the Indonesian Ministry of Agriculture No 70. All data were below the limit whereby two configurations gave the least values of potentially toxic elements, which might be linked to the role of siphon in giving a favourable condition for preventing the release of the heavy metals trapped in the cell walls. Keywords: Sargassum- Siphon- Liquid Fertilizer- Plactic Bottle- Heavy Metals Share Link | Plain Format | Corresponding Author (Nurhayati Nurhayati)

63	Interdisciplinary Physics	ABS-126
Estimation of Fish Feed Pellet Scattering Distribution From Automatic Feeder By Utilizing Particle Kinematics and Digital Image Processing Fajar Mukharom Darozat Institut Teknololgi Bandung, PT. Multidaya Teknologi Nusantara Abstract Measuring the distribution of feed pellets throwed by an automatic feeder manually is technically difficult and requires a lot of energy and costs. This research aims to create an estimator of feed scattering distribution using kinematics of motion of the ejected feed particles based on the position of the particles obtained using digital image processing. Six different types of pellets, 150 gr each were used as samples. A screen was placed in front of the pellet thrower. Each pellet that hitting the screen will leave a mark. Picture of the screen with collision marks then captured using smartphone camera. Each image then digitally modified by applying perspective correction and color manipulation to increase contrast between collision marks and background. The coordinate points of collision between the pellet and the screen are mapped using blob detection technique. By utilizing the coordinates of the point of impact and the speed of the feed throw, an estimation of pellet location when reaching the surface of the pond can be made. Keywords: Aquaculture, Digital Image Processing, Particle Kinematics Share Link | Plain Format | Corresponding Author (Fajar Mukharom Darozat)

64	Interdisciplinary Physics	ABS-142
DEVELOPMENT OF PAPER TOWELS BASED ON WATERMELON RIND (Citrullus lanatus) AS AN EFFORT TO IMPROVE THE CLEAN LIFE IN THE NEW NORMAL ERA OF COVID-19 Septia Ardiani, Antinah Latif Politeknik Negeri Media Kreatif Abstract Preventing infection in the new normal of COVID-19 is important so that the spread of infectious diseases can be controlled. Various types of products have been developed to improve public health, including the prevention of infectious diseases caused by various microbes such as bacteria, viruses, fungi, and other pathogens. The paper towels used by the community are one of the sanitation products that are currently an important commodity for improving a healthy and clean lifestyle. Watermelon rind is a waste fruit peel that has not been used properly and even it has the potential to be an alternative raw material for making paper products due to the content of lignin, cellulose, etc. The aim of this research is to develop sanitizing products in the form of paper towels containing antimicrobials from watermelon skins so that they can improve a clean lifestyle and prevent various infectious diseases. This research method starts with pulp making which is divided into five stages, namely drying, pulping, bleaching, and printing. After that, the product was tested using the FTIR test to determine the contents of the paper towels. Next, the characterization of the physical properties includes basis weight, absorption, tensile strength and tear resistance. Keywords: Paper Towels, Antimicrobial, Waste of Watermelon Rind, Physical Characterization Share Link | Plain Format | Corresponding Author (Septia Ardiani)

65	Interdisciplinary Physics	ABS-168
The Space-Time Autoregressive Modelling with Spatial Correlated Errors for The Number of Vehicles in Purbaleunyi Toll Gates U. Mukhaiyar, F. T. Nabilah, and U.S. Pasaribu Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung Abstract The space-time modelling considers the observations dependence based on time and spatial simultaneously. One of popular models used is the Generalized Space-Time Autoregressive (GSTAR). Most of the GSTAR class models assumed that the errors are uncorrelated and normal distributed. In fact, the dependence of errors is exist. In this paper, the GSTAR model is assumed to have the time correlated errors. The convergence of the parameter estimators is evaluated and the weak consistency is obtained. The illustration is performed by using the number of vehicles passed through Purbaleunyi toll gates. For this data, the GSTAR models be applied and compared between the uncorrelated and time correlated errors assumption of modeling. It is obtained that the GSTAR(1-1) model with time correlated errors, is more appropriate model to predict the number of vehicles passed through the Purbaleunyi toll gates. This appropriate model is well performed when the minimum number of time observations is more than sixty observations. Keywords: space-time model, autoregressive, time correlated errors, weak consistency, stationarity Share Link | Plain Format | Corresponding Author (Utriweni Mukhaiyar)

66	Magnetism and Photonics	ABS-7
The Optical Response of Metallic Spherical Core-Shell Nanoparticles Fitriyadi (a*), Azrul Azwar (b), Fatimah Arofiati Noor (a) a) Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132, Indonesia *fitriyadi567[at]gmail.com b) Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Tanjungpura, Pontianak 78124, Indonesia Abstract The optical response of spherical nanoparticles was studied based on the quasi-static approximation of classical electrodynamics. The simple Drude model was used to calculate the complex dielectric function of the metal. We investigated the behavior of the absorption cross-section spectra of metallic spherical core-shell (including dielectric-metal and metal-dielectric) nanoparticles numerically. We found that the number of resonance peaks in the absorption cross-section spectra depends on the number of metal-dielectric interfaces of the nanostructure, as predicted by plasmonic hybridization theory. Furthermore, the absorption cross-section spectra can be precisely controlled by changing the thickness of the shell and the dielectric constant of the medium. Keywords: Optical response- Drude model- Core-shell nanoparticles Share Link | Plain Format | Corresponding Author (Fitriyadi Fitriyadi)

67	Magnetism and Photonics	ABS-54
Optimization of Metal Nanoparticles Concentration into Dye Solution to Enhance Performance of Dye Sensitized Solar Cells Setiya Rahayu, Amaldeus Tani Dosi, Priastuti Wulandari* Physics of Magnetism and Photonics Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132, West Java, Indonesia *wulan[at]fi.itb.ac.id Abstract Dye-sensitized solar cells (DSSCs) offer a promising alternative to the silicon-based solar cells due to their potential advantages, such as low-cost materials, non-vacuum fabrication process and hence being considered as an environmentally friendly technology. Following the first report by O^Regan and Gratzel in 1991, many researchers have investigated the crucial processes in DSSC characteristics, such as the photon absorption of the dye molecules that are commonly impregnated into a TiO2 mesoporous electrode. In recent years, it has been considered the use of metal nanoparticles into the structure of solar cells device to increase light adsorption since there is excitation of localized surface plasmon resonance (LSPR) on the nanoparticle surface. In this study, we incorporate gold or silver nanoparticles into dye solution in order to enhance the light absorption in dye-sensitized solar cells (DSSCs) device. We also compare the performance of DSSCs incorporated AuNP and AgNP with various capping organic molecules on nanoparticles. Each of metal NPs was mixed with N-719 dye solution and we optimized the metal NPs used into the dye solution. The characterizations of the mixture solution were done by use of UV-Vis and FT-IR spectroscopies while the morphology of the solution was captured by TEM imaging. The performance of DSSCs were done by J-V measurement with solar simulator 100mW of power. Our fabricated DSSC devices show the enhancement of current density and power conversion efficiency (PCE) when metal NPs added into dye layer. Addition of gold nanoparticle capped by oleylamine (AuOA) 6.227 wt% reveals the enhancement of PCE devices from 1.58% without AuOA to 2.60% with AuOA. Similar case for addition AuDT and AgSC8 into dye layer of DSSC show the same tendencies. Keywords: Dye sensitized solar cells, gold dan silver nanoparticles, LSPR, J-V characteristics Share Link | Plain Format | Corresponding Author (Setiya Rahayu)

68	Magnetism and Photonics	ABS-55
Incorporation of Perovskite Cs2SnI6 into Dye Sensitized Solar Cell Structure and Its Optimization Amaldeus Tani Dosi, Setiya Rahayu, Priastuti Wulandari* Physics of Magnetism and Photonic Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung Jl. Ganesha 10 Bandung 40132, West Java, Indonesia *wulan[at]fi.itb.ac.id Abstract Dye Sensitized Solar Cell (DSSC) technology has become considerable research in the last two decades in the field of energy conversion. DSSC is one of the most promising types of solar cells among third generation solar cells due to the ease of fabrication process. Several studies have been conducted to improve DSSC performance, for example by modifying the structure of DSSC or by adding materials such as lead and tin-based perovskite, as well as gold and silver metal nanoparticles. On the other hand, lead-based perovskite (Sn) is considered to replace lead-based perovskite (Pb) because the Pb is toxic, and it has a negative impact on the environment. It has been known that Cs2SnI6 perovskite material is more stable in air and can be synthesized in an air environment. In this study, we attempt to incorporate Cs2SnI6 perovskite into N-719 dye solution to increase photon absorbance or to enhance electron transport regarding to enhance the performance of DSSC. In our experiment, Cs2SnI6 was successfully synthesized chemically at room temperature by mixing cesium carbonate (Cs2CO3) into of hydroiodic acid (HI) as a solvent and stannic iodide (SnI4) in warm ethanol to form a precipitate. The absorbance spectra of Cs2SnI6 perovskite show two specific peaks at wavelength of 293 nm and 362 nm. The energy band gap obtained by the Tauc-Plot method is about 3.1 eV. The performance of our fabricated DSSC device was done by J-V measurement. In our experiment, the addition of 1 mg/mL of Cs2SnI6 perovskite solution into DSSC structure reveals the highest PCE value of 3.97%. However, the PCE value was drastically reduced from 4.03% in the 1st week to 1.07% in the 9th week for the case of addition ethanol solvent in perovskite. Keywords: Dye Sensitized Solar Cell (DSSC), Cs2SnI6 perovskite. Share Link | Plain Format | Corresponding Author (Amaldeus Tani Dosi)

69	Magnetism and Photonics	ABS-58
Density Functional Theory Study of Oxygen Deficiencies in \(\textrm{SrCoO}_3\) Kevin Wilbert (a*), Abdul-Muizz Pradipto (b), and A. Agung Nugroho (b) Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha No 10, Bandung 40132, Jawa Barat, Indonesia Abstract Strontium Cobaltite \(\textrm{SrCoO}_3\) is an oxide material that belongs to the perovskite class which exhibits interplays between spin, charge, and orbital degrees of freedom. The rich physical properties of \(\textrm{SrCoO}_3\) enable various potential applications such as magnetoresistance materials, ceramics membranes for oxygen separation, and cathode materials of solid oxide fuel cells. Recent reports indicate a possibility to manipulate the oxygen content of \(\textrm{SrCoO}_3\) by utilizing external perturbations such as external electric field or strain. Such modification will affect the electronic and magnetic properties of the material. In this study, the effects of oxygen deficiency from SrCoO3 are investigated using spin-polarized Density Functional Theory as implemented in the Full-potential Linearized Augmented Plane Wave (FLAPW) method, by explicit consideration of the correlation effects of the localized electrons in the Co 3d orbitals using the effective Hubbard \(U_{eff}\) parameter. The effective term is chosen to consist of the subtraction between the \(U\) value of 3 eV to denote the Coulomb interaction and the Hund^s coupling parameter \(J\) of 0.95 eV. Our results show that the localized character of the Co 3d orbitals is strongly changed by the modification of the oxygen content. The magnetic exchange interaction between two neighboring Co ions is therefore altered. As one of the consequences, the change of magnetic ground state is observed using the same \(U_{eff}\), where a ferromagnetic ordering is obtained on the full oxygen content, while \(\textrm{SrCoO}_{2.5}\) shows an antiferromagnetic behaviour. Keywords: SrCoO3, DFT, FLAPW Share Link | Plain Format | Corresponding Author (Kevin Wilbert)

70	Magnetism and Photonics	ABS-65
Incorporation of Gold Nanoparticles in PEDOT:PSS Layer for Bulk Heterojunction Solar Cell Application Nur Fadhilah Syarif (a), Rahmat Hidayat (a), Priastuti Wulandari (a*) a) Physics of Magnetism and Photonics Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132, West Java, Indonesia *wulan[at]fi.itb.ac.id Abstract Gold nanoparticles (AuNPs) have unique optical properties called Localized Surface Plasmon Resonance (LSPR). LSPR is an optical phenomenon generated by light wave trapped within conductive material that have dimension <10 nm. In this case, AuNPs have a diameter that close to the incident wavelength, resulted in collective oscillation of electron in conduction band. In this research, we study optical and chemical properties of AuNPs incorporate into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solution and the performance of hybrid bulk heterojunction (BHJ) solar cell based on addition of AuNPs into PEDOT:PSS as hole transport layer. Usually, the amphiphilic surfactant molecules is added into PEDOT:PSS to enhance wettability of PEDOT:PSS layer when it combine into hybrid solar cell structure. AuNPs preparation were done by use of modified reduction method with organic capping molecules such as citrates, 3-mercaptopropionic acid and oleylamine. The characterizations of AuNPs interaction with PEDOT:PSS were done by UV-Vis and FTIR spectroscopies while the morphology and shape of AuNPs were captured by TEM imaging. We also compared the performance of solar cell devices based on poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) and PEDOT:PSS incorporated AuNPs. Typical plasmonic peak of AuNPs are clearly shown in the absorbance spectra as indicate from homogenous particle size and shape. However, its plasmonic peaks relatively shifted and overlapped when the nanoparticles are added into active polymer solution. The fabricated BHJ solar cell devices incorporated AuNPs will be performed in comparison to that of reference devices without gold nanoparticles. Keywords: Gold Nanoparticles- PEDOT:PSS- localized surface plasmon resonance- electron transport layer- hybrid bulk heterojunction solar cell Share Link | Plain Format | Corresponding Author (Nur Fadhilah Syarif)

71	Magnetism and Photonics	ABS-79
Tuning the Dzyaloshinskii-Moriya Interaction in Fe/MgO-based Thin Films Abdul-Muizz Pradipto (1) and Kohji Nakamura (2) (1) Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia (2) Department of Physics Engineering, Mie University, Japan Abstract The development of spintronics technology has been in part accelerated by the discovery of the Tunneling Magnetoresistance (TMR) effect, which can be realized by sandwiching ferromagnetic metal layers by an insulating barrier, such as Fe/MgO/Fe multilayers. At the proximity between the two materials, i.e. between Fe and MgO, exotic magnetic and transport phenomena differing from those at the pure system can take place due to the interfacial effects. It has been a common knowledge that understanding and controlling these properties at the interfaces is crucial in order to reach an optimum design of spintronic devices. In this work, the Dzyaloshinskii-Moriya interaction (DMI) in Fe/MgO thin films is investigated by using the Density Functional Theory (DFT) approach as implemented in the Full-potential Linearized Augmented Plane Wave (FLAPW) method. An atomic layer of heavy metal element M (M=Os, Ir, Pt, and Au) is inserted in between the two materials to enhance the spin-orbit coupling strength. Our calculations show that the introduction of the heavy metal layer alters the sign of DMI which implies the change in the magnetic chirality. When an external electric field associated to the application of electric gate voltages is introduced, the value of DMI is modified, and the modification is related to the change in the orbital magnetic moments. Since the DMI is responsible for various macroscopic properties such as magnetic textures or domain sizes, these results suggest the possibility to tune these properties via the application of external gate voltages. Keywords: Spintronics, Density Functional Theory, voltage-controlled properties Share Link | Plain Format | Corresponding Author (Abdul Muizz Pradipto)

72	Magnetism and Photonics	ABS-149
THE EFFECT OF MOLECULAR ORIENTATION IN DISPERSE RED 1 (DR1) FILM ON ITS REFRACTIVE INDEX H. Herman (*). I.G. Narayana, R. Hidayat Physics of Magnetics and Photonics Reserch Division Faculty of Natural Sciences and Mathematics Bandung Institute of Technology Ganesha 10 Bandung 40132. *herman[at]fi.itb.ac.id Abstract The refractive index of materials is an important physical quantity in the design of various photonic devices. For thin-film based devices, the fabrication method should be compatible with existing processes in microelectronic fabrication and allow for control of the refractive index. In this research, the material used is polar Dispersion Red 1 (DR1) molecule. The film fabrication is carried out using the physical vapor deposition method which has been equipped with an electric polling installation. The poling of the electric field during the deposition process is applied perpendicular to the substrate. The thickness measurement of the films was carried out using a reflectometer where the light was incident perpendicular to the substrate. The refractive index was determined by the multiple beam interference method. As the results, we obtained that the refractive index of thin film will decrease as the electric field increased. Keywords: DR1, EFA-PVD, refractive index, molecular density, molecular orientation Share Link | Plain Format | Corresponding Author (Herman Herman)

73	Magnetism and Photonics	ABS-163
Calculation of spectra and plasmon wave distribution in one dimensional periodic structure Alvin Fariz (1), Rahmat Hidayat (1*) 1) Institut Teknologi Bandung, Physics of Magnetism and Photonics Research Division, Physics Program Study, Faculty of Mathematics and Natural Sciences, Jl. Ganesha 10, Bandung, West Java, 40132, Indonesia *Corresponding author: rahmat[at]fi.itb.ac.id Abstract Surface Plasmon Resonance (SPR) is a resonance phenomenon between electromagnetic waves and electrons, which is formed on the interface between metal and dielectric surface. SPR waves can be generated by using a coupler element, such as prisms and gratings. In this study, we analyze the effect of groove filling in nanograting structure using computation work based on Rigorous Coupled Wave Analysis (RCWA) method. The structure periodicity is 700 nm with the groove depth of around 350 nm. The reflectance spectra calculation by RCWA method produces the appearance of SPR dip for empty groove (with air inside the groove) at around 550 nm - 650 nm and near infra red region. The dip wavelength varies on the incident angles from 30 up to 60 degree. In addition, the shifting of those dips are also predicted form the calculation results when the groove is filled by a medium with refractive index of 1.5, which can be the basis of its utilization as optical sensing element. Keywords: Plasmonic Nanograting- Rigorous Coupled Wave Analysis- Surface Plasmon Resonance Share Link | Plain Format | Corresponding Author (Alvin Fariz)

74	Materials Physics	ABS-17
Ultrafast Laser Texturing of Copper Metal Surface: Superhidrophobicity and UV-NIR Reflectance Properties Yuliati Herbani (a*), Nursidik Yulianto (a,b), Kirana Yuniati Putri (a), Affi Nur Hidayah (a) Hutomo Suryo Wasisto (b) a) Research Center for Physics, Indonesian Institute of Sciences, Jl Riset, Gedung 442, Kawasan Puspiptek Serpong, Setu, Tangerang Selatan, Banten, Indonesia, 15314 *yuliati.herbani(at)lipi.go.id b) Laboratory for Emerging Nanometrology (LENA), Technische Universitat Braunschweig, Langer Kamp 6, D38106 Braunschweig, Germany Abstract Functional surfaces are key components of nearly every mechanical device and they have become a special focus in both academia and industry. The no contact, one step, direct, and maskless laser surface texturing technique is one of the most encouraging approaches for realizing the surface functions. We use a high power and high repetition rate ultrafast laser system to produce nano structures on metal surfaces. We demonstrate that metal surface nano structures and correspondingly their wetting property and the optical responses can be facilely tailored by simple controlling the ultrafast laser processing parameters. A surface nanostructures with nano particles of tens to hundreds nm have been fabricated on copper (Cu) surfaces. The wetting property was found to be superhydrophobic with a maximum contact angle of 143.2. Surface reflection of copper surfaces has been tuned from 10% to 90% in spectra level from UV to NIR in spectrum range, with unique optical properties like visible selective reflection, linear changing reflection, band reflection, and broadband absorption being achieved. The formation processes of those particle structures as well as the underlying mechanisms for their wetting property and optical responses are discussed. Keywords: femtosecond laser texturing- superhydrophobicity- UV-NIR reflectance Share Link | Plain Format | Corresponding Author (Yuliati Herbani)

75	Materials Physics	ABS-33
The Study of the Swelling Degree of the PVA Hydrogel with varying concentrations of PVA Nabila Asy-Syifa (a), Kusjuriansah (a), William Xaveriano Waresindo (a), Dhewa Edikresnha (a), Tri Suciati (b), Khairurrijal Khairurrijal (ac*) (a)Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia (b)Department of Pharmaceutics, School of Pharmacy, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia (c)University Center of Excellence - Nutraceutical, Bioscience, and Biotechnology Research Center, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia E-mail: krijal[at]fi.itb.ac.id Abstract Hydrogel is composed of a three-dimensional network of hydrophilic polymers and can swell when placed in an aqueous media. Polyvinyl alcohol (PVA) is a common polymer used to produce hydrogels because it has biocompatibility, non-toxicity, chemical stability, low cost, and excellent mechanical strength. In this study, the PVA solutions were prepared with concentrations of 6%, 8%, 10%, and 12% in distilled water. The precursor solutions underwent a freeze-thaw cycle with a freezing temperature of -25&#8451- for 20 hours and a thawing temperature of 37&#8451- for 4 hours and carried out for 6 cycles. The swelling degree and the gel fraction of the hydrogel were then determined. From the swelling degree results, the increase of the PVA concentration in the precursor solutions reduced the swelling degree of the hydrogel. Based on the gel fraction test, it was revealed that all PVA concentrations have approximately the same value of gel fraction at 97%. Additionally, the viscosity and the density were also measured. Both showed an increasing trend with the addition of PVA concentration, where the viscosity values from the smallest to highest concentrations were 12.4944, 34.1737, 93.8491, and 216.2979 cP while the density values were 0.9865, 0.9871, 0.9878, and 0.9885 gram.cm-3. Keywords: Hydrogel- Polyvinyl alcohol- Swelling Degree- Gel Fraction Share Link | Plain Format | Corresponding Author (Nabila Asy Syifa)

76	Materials Physics	ABS-52
Lithium Doping Effect on Microstructural and Electrical Properties of ZnO Thin Films Grown by Metal Organic Chemical Vapor Deposition Muhammad Arief Mustajab (a*), Toto Winata (a), Pepen Arifin (a), Suprijadi (b) a) Physics of Electronic Materials Research Group, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia *arief[at]fi.itb.ac.id b) Instrumentation and Computation Research Group, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia Abstract The undoped and Li-doped ZnO thin films were grown on Si(100) substrate using metal organic chemical vapor deposition (MOCVD). Zinc acetylacetonate hydrate and lithium acetylacetonate solution were used as ZnO thin film precursor and Li dopant source respectively. Lithium incorporation into ZnO thin films were confirmed using energy dispersive X-ray spectroscopy (EDX). The effect of lithium doping on microstructural were characterized using scanning electron microscope (SEM) and X-ray diffractometer (XRD). XRD diffractogram analysis shows that undoped and Li-doped ZnO thin films have polycrystalline hexagonal wurtzite structure having preferred peak crystal orientation of (002). Li doping decrease the lattice parameters and cell volume of ZnO thin films. From SEM observation, surface morphology of ZnO thin films slightly affected by Li doping. Current-voltage (I-V) measurement and four-point probe method were used to measure electrical properties of lithium doped ZnO thin films. Electrical conductivity of ZnO thin films increase as Li doping given. Keywords: Li doped ZnO- Zinc acetylacetonate- Lithium acetylacetonate- MOCVD Share Link | Plain Format | Corresponding Author (Muhammad Arief Mustajab)

77	Materials Physics	ABS-60
Influence of fumed silica and PMMA on optical properties of blue-emitting CH3NH3PbBr3 perovskite nanocrystals Auliya Rahmatul Ummah(a), Ea Cahya Septia Mahen(a,b), Bebeh Wahid Nuryadin(c), Ferry Iskandar(a,*) (a) Department of Physics, Institut Teknologi Bandung, Bandung, Indonesia (b) Department of Physics Education, UIN Sunan Gunung Djati, Bandung, Indonesia (c) Department of Physics, UIN Sunan Gunung Djati, Bandung, Indonesia *Corresponding Author: ferry[at]fi.itb.ac.id Abstract Fabricating highly efficient and great optical properties of blue organic-inorganic halide perovskite (OIHP) has proven difficult and continues to be a source of significant interest. Herein, we successfully synthesized blue-emitting CH3NH3PbBr3 perovskite using a ligand assisted reprecipitation process, followed by embedding in fumed silica and poly-methylmethacrylate (PMMA) matrix. By adding fumed silica, the photoluminescence (PL) peak spectrum of CH3NH3PbBr3 was blue-shifted from 481 to 477 nm. Furthermore, OIHP also exhibited a blue shift from 477 nm to 471 nm after being embedded in the PMMA matrix. On the other hand, the OIHP absorbance spectrum shifted from 451 nm to 426 nm, which correlates to the blueshift in the PL peak spectrum. The emergence of two peaks in the absorbance spectrum indicates that nanoparticles with small size distribution have grown on the OIHP. This phenomenon demonstrates that the OIHP has a strong quantum confinement effect. Therefore, the results demonstrated that CH3NH3PbBr3/SiO2/PMMA composite films have great optical properties, which is promising for their uses in potential optoelectronic applications. Keywords: Perovskite, Silica, PMMA, Optical Properties Share Link | Plain Format | Corresponding Author (Ferry Iskandar)

78	Materials Physics	ABS-62
The Influence of NaOH concentration on the structural and morphological properties of nanoparticles Ni0.4Zn0.5Co0.1Fe2O4 synthesized by coprecipitation N I M Aturroifah (a), N E A Wahyuni (a), A S N Hidayah (a), S Zuhroh (a), Hartatiek (a,b), A A Sukkaew (c), R Kurniawan (a,b) and J Utomo (a,b)* a) Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia. b) Center of Advanced Materials for Renewable Energy, Universitas Negeri Malang, Jl. Semarang, Malang, 65145, Indonesia. *joko.utomo.fmipa[at]um.ac.id c) Department of Renewable Energy Technology, Faculty of Science Technology and Agriculture, Yala Rajabhat University, 95000, Thailand. Abstract Ni0.4Zn0.5Co0.1Fe2O4 nanoparticles have been synthesized using the coprecipitation method with the different concentration of NaOH coprecipitant. The synthesis was carried out at a synthesis temperature of 90 degree celcius and the concentration of NaOH was varied by 5 M, 7 M, 9 M and 12 M. X-ray diffraction (XRD) and transmission electron microscopy (TEM) was used to analyze structural and morphological properties of Ni0.4Zn0.5Co0.1Fe2O4 nanoparticles. The crystallite size of Ni0.4Zn0.5Co0.1Fe2O4 nanoparticles calculated by the Scherrer equation decreased in size with increasing NaOH concentration. The lattice parameters of Ni0.4Zn0.5Co0.1Fe2O4 nanoparticles with 5 M NaOH concentration of 8.380 angstrom and high crystallinity. The resulting diffraction pattern is a cubic spinel structure with a single phase at the highest diffraction peak of 35.5 degree i.e. plane (311). Vibration bands in Ni0.4Zn0.5Co0.1Fe2O4 nanoparticles based on variations in NaOH concentration were obtained through fourier transform infra red (FTIR) analysis which resulted in the formation of metal ion vibrational bands. The absorption peak of the octahedral site was Investigated at 487.14 cm-1, while the absorption of the tetrahedral site was placed at 689.3 cm-1. This is in good agreement with the characteristic of spinel structure having tetrahedral and octahedral sites. Keywords: Ni0.4Zn0.5Co0.1Fe2O4, nanoparticles, coprecipitation, NaOH concentration Share Link | Plain Format | Corresponding Author (Nuviya Illa Muthi Aturroifah)

79	Materials Physics	ABS-64
Nanosilica Particulate Magnetic and Titanate Coupling Agent as Alternative Filler on Natural Rubber Composites with Human-Tissue-Like Mechanical Characteristic Riri Murniati (1*), Putrya Hawa (2) and Mikrajuddin Abdullah (3) 1 Department of Physics, Indonesia Defense University, IPSC Sentul, Bogor 16810, Indonesia *ririmurniati90[at]gmail.com 2 Department of Medical, Indonesia Defense University, IPSC Sentul, Bogor 16810, Indonesia 3 Department of Physics, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia Abstract This study has investigated the effect of magnetically modified natural zeolite on nanosilica-reinforced natural rubber composites that has a mechanical characteristic similar to human tissue. We use technical specifications rubber (TSR) SIR 20 with nanosilica reinforced fillers and Titanate coupling agent (TCA) as filler and elastomer binders. The results showed that nanosilica-zeolite-magnetite (Fe3O4) mixture had an influence on strength and stiffness and could be a substitute for Carbon Black. The relationship between crosslink density, mechanical properties and damping properties were explored. We also identified that improved properties were produced by modification of white oil softeners and fillers of nanosilica-zeolite-magnetite mixtures. The precursors made with some variations include the optimization of the type of base material used rubber, optimization type of filler, optimization volume fraction of nanosilica, and optimization crumb rubber softener. Samples characterized by using Universal Testing Machine and then tested with the incision test equipment that specially designed by our own team. The results of magnetically modified zeolite on nanosilica-reinforced natural rubber composites showed that crosslink density, mechanical properties and damping properties increased significantly. Mechanical characteristics of different human body part tissue were compared to the control samples and resulted samples that have similar mechanical characteristics with internal human tissue characteristic. Based on these results, nanosilica fillers combine with magnetically modified zeolites and titanate coupling agent, potentially replacing carbon black and applicative for synthetic muscle replacement cadavers with a customized formula. Keywords: zeolite, artificial muscles, mechanical properties, nanosilica, TCA Share Link | Plain Format | Corresponding Author (Riri Murniati)

80	Materials Physics	ABS-66
Photovoltaic Performance of TiO2 Mesoporous Films with Different Working Areas for Dye-sensitized Solar Cell Nasikhudin1, Nadiya Ayu Astarini1, Muhamad Fadhil Rahman1, Aripriharta1, Zurina Osman3, and Markus Diantoro1,2,a 1Departement of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang No. 5 Malang 651145 2Center of Advanced Materials for Renewable Energy, Universitas Negeri Malang, Jl. Semarang No. 5 Malang 651145 3Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, W. Persekutuan Kuala Lumpur, Malaysia Abstract The enhancement of performance efficiency in Dye-sensitized Solar Cells (DSSC) could be optimized through the working area of the mesoporous TiO2 photoanode. A small working area will increase the photovoltage and power conversion efficiency. In comparison, a large working area will increase the recombination rate and slow down the photon particle transport rate at the photoanode. The TiO2 photoanode layer consists of a blocking layer deposited using a spin coating technique. While the mesoporous paste was deposited by screen printing method with three variations working areas (0.25, 0.30, and 0.56 cm2). The samples were characterized using XRD, SEM-EDX, UV-Vis spectroscopy, and solar simulator. XRD characterization confirmed that the TiO2 photoanode had an anatase phase. Based on SEM analysis, it is known that mesoporous TiO2 has a large surface area indicated by a porosity level of 70%. The elemental analysis of TiO2 were confirmed by EDX characterization that shows the presence of Ti and O peaks. The absorption spetra of the mesoporous TiO2 photoanode which has been soaked in 0.07 mM N719 dye solution has absorbance for wavelengths in the ultraviolet to the visible light range . In this work, the J-V characterization shows that for cell with a working electrode area of 0.25 cm2 exhibits promising power conversion efficiency up to 2.5% and circuit current density of 14 mA cm-2 under an illumination light of 100 mW/cm2. Keywords: Dye-sensitized solar cell, TiO2 mesoporous, working area, efficiency Share Link | Plain Format | Corresponding Author (Nadiya Ayu Astarini)

81	Materials Physics	ABS-68
Thermoelectrics of type-I and type-II nodal line semimetals within the two-band model Jyesta Mahayu Adhidewata (a*), Ahmad Ridwan T. Nugraha (b**), Eddwi H. Hasdeo (b)(c), Bobby Eka Gunara (a***) (a) Theoretical High Energy Physics Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132, Indonesia *jyesta.mahayu[at]s.itb.ac.id (b) Research Center for Physics, Indonesian Institute of Sciences (LIPI), Tangerang Selatan 15314, Indonesia **ahmad.ridwan.tresna.nugraha[at]lipi.go.id (c) Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg, Luxembourg ***bobby[at]fi.itb.ac.id Abstract Metals and semimetals are often considered bad thermoelectric (TE) materials due to their low Seebeck coefficients. However, in this work, we would like to show that topological semimetals in the class of nodal-line semimetals could potentially have a higher than average performance as TE materials. Nodal-line semimetals (NLSs) are bulk semimetals with an intersection between the conduction band and valence band in the form of a line (thus called the nodal line). We construct a two-band model using an almost-linear conduction and parabolic (or Mexican-hat) valence bands which overlap near the band edge to represent a type-I (or type-II) NLS. We calculate TE properties of the NLSs using the semiclassical Boltzmann transport theory with the relaxation time approximation. We expect to obtain a large enough Seebeck coefficient from the presence of a discontinuity in the density of states due to band overlap. Here we seek to optimize the parameters of our model which will hopefully allow us to determine potential candidates for TE materials among semimetals. Keywords: Boltzmann transport equation, nodal-line semimetal, thermoelectrics Share Link | Plain Format | Corresponding Author (Jyesta Mahayu Adhidewata)

82	Materials Physics	ABS-69
Investigation of the Post-Static Fire Test Effect on the RX320 Rocket Motor Nozzle Through Mechanical Properties Testing of Graphite Material Setiadi (a*), Bagus Wicaksono (a), Fajar Ariwandono (b), Nurul Lailatul Muzayadah (b), Taufiq Satrio Nurtiasto (b) a ) Rockets Technology Centre, National Institute of Aeronautics and Space (LAPAN), Indonesia *seti1159[at]gmail.com, bagus_wicaksono2002[at]yahoo.com b ) Aeronautics Technology Centre, National Institute of Aeronautics and Space (LAPAN), Indonesia Abstract Abstract. Rocket nozzle is a crucial and complicated part of a rocket, primarily for rocket RX320. Its function is to control the exhaust flow, so the rocket gets the maximum possible amount of forward thrust. However, Graphite materials are materials used inside rocket due to good mechanical properties and high melting temperatures resistance. This study discussed the effect of post-static rocket fire testing on the mechanical properties of graphite materials compared to graphite technical data sheet (TDS). Mechanical properties testing has been done to determine the average value of flexural strength with the three-point bending test method and the average value of the compressive test. The graphite has an average three-point bending test value of 40.185 MPa, with an average elastic modulus of 0,656 GPa. Furthermore, the average compressive test of graphite has a value of 67.71 MPa, with an average load of 1560 N. The mechanical properties trends are slightly decreasing due to post static fire testing compared to TDS. It was around 23,94 % for flexural strength and 49.95% for compressive strength. Keywords: graphite, nozzle, rocket, three-point bending test, compressive test Share Link | Plain Format | Corresponding Author (BAGUS WICAKSONO)

83	Materials Physics	ABS-71
Surface stability and electronic structure of CuNi alloy (111) as a potential catalyst for graphene growth-a density-functional theory study Erik Bhekti Yutomo, Fatimah Arofiati Noor, Toto Winata Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40131, INDONESIA Abstract Controlling the number of graphene layers during its growth process is essential in realizing its practical application as a transparent conductive electrode. Based on the experimental results, growth with CuNi alloy catalysts can effectively control the number of graphene layers. However, research at the experimental level has not been supported by research at the theoretical level. Therefore, we will study the growth of graphene on a CuNi alloy catalyst using the density functional theory (DFT) method. However, in this paper, we only focus on studying the stability of the surface system of CuNi using the DFT method as a preliminary study. Based on geometry optimization, CuNi (111) has a wrinkled surface in the slab model due to the anisotropy shift of the atoms in the first layer. Furthermore, CuNi (111) has a surface energy of J/m^2 , which is between the surface energies of its components. This condition indicates that CuNi (111) has excellent stability. When forming CuNi alloy, electrons in the Cu 4s and Ni 3d orbitals have an enormous contribution in forming the metallic bonds indicated by a significant shift of the band center energy and considerable change of the number of states at the Fermi level. Our results show that the CuNi surface system can potentially be a catalyst for graphene growth in future studies. Keywords: Band center energy, catalyst, CuNi alloy, surface energy. Share Link | Plain Format | Corresponding Author (Erik Bhekti Yutomo)

84	Materials Physics	ABS-77
Magnetizations of Dirac fermions M Shoufie Ukhtary(a*) , F. Rizki Pratama (b), Riichiro Saito (b) a) Research Center for Physics, Indonesian Institute of Sciences * msho001[at]lipi.go.id b) Department of Physics, Tohoku University Abstract Graphene and related two-dimensional materials are known to possess intrinsic orbital diamagnetism (OD), which is originated from the coalescence of states of the Dirac fermions at the valence bands to form the zeroth Landau levels (LLs) in the presence of an external magnetic field B. Magnetizations is used to characterize the OD of graphene. A method to calculate the magnetization is by using the Euler-Maclaurin summation formula, however, this method gives divergent magnetization since the summation of the infinite number of the occupied LLs at the valence bands should be included. In this work, we analytically calculate the magnetizations for strong magnetic field/low temperature and weak magnetic field/high temperature limits with the method of zeta function regularization, in order to avoid the divergence in the expression of magnetization. Our formula reproduces the experimental observation of the magnetization of graphene. In the case of gapped Dirac fermions, a large band-gap gives a smaller but more robust magnetization with respect to temperature. In the doped system, we also observe the oscillation of magnetization with respect to magnetic field. Keywords: Magnetization, Graphene, Dirac Fermions Share Link | Plain Format | Corresponding Author (M Shoufie Ukhtary)

85	Materials Physics	ABS-78
Rietveld study on the effect of pelletizing and sintering towards the structural evolution of Li1.3Al0.3Ti1.7(PO4)3 Ahmad Sohib (a), Joti Karunawan (b), Citra Deliana Dewi Sundari (c), Octia Floweri (b), and Ferry Iskandar (a,b,*) (a) Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, Indonesia (b) Research Center for Nanosciences and Nanotechnology (RCNN), Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, Indonesia (c) Inorganic and Physical Chemistry Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, Indonesia *Corresponding author: ferry[at]fi.itb.ac.id Abstract Lithium aluminium titanium phosphate, Li1.3Al0.3Ti1.7(PO4)3 (LATP), is a highly potential ceramic material for solid electrolyte (SE) in an all-solid-state battery (ASSB) thanks to its superior ionic conductivity. The crystallinity of the ceramic material plays an important role in determining the ionic conductivity, ensuring the excellent performance of ASSB. To be applied in the ASSB system, LATP should be pressed into a disc and then sintered at a high temperature to improve its crystallinity. This research aims to investigate the effect of pelletizing and sintering on the crystallinity of LATP. LATP powder was synthesized via a sol-gel method followed by calcination at 850 degree Celsius for 5 hours in the air. The obtained powder was mechanically pressed (20 MPa) into pellets and sintered at 1000 degree Celsius for 3 hours. Morphology and structural features of the LATP samples (powder and pelletized samples) were characterized using a scanning electron microscope (SEM) and X ray diffraction (XRD), respectively. The results demonstrated that the particle size of LATP in the pelletized samples are larger than the powder one. This morphology possibly contributes to the lower internal resistance of LATP and, therefore, higher ionic conductivity. Rietveld refinement analysis showed that the crystalline properties of LATP changed after pelletizing and sintering treatment. This research demonstrated the importance of pelletizing and sintering process to achieve high ionic conductivity of LATP. Keywords: LATP, pelletizing, sintering, Rietveld refinement Share Link | Plain Format | Corresponding Author (Ferry Iskandar)

86	Materials Physics	ABS-81
Machine learning for effective on-site Coulomb interaction parameters in transition metal oxides in DFT+U method Takahiro Matsumoto, Kenji Nawa, Koji Nakamura Graduate school of Engineering, Mie University Abstract Theoretical understanding of strongly-correlated magnetic materials is of importance for realizing novel magneto-optical device. To treat large complex systems, however, calculations may be practically limited due to huge computational resources demanded. In order to overcome this problem, we have combined neural network technique to density functional theory (DFT+\(U\) method), and applied to NiO as test calculations and extended to yttrium iron garnet (YIG) that contains 160 atoms in a unit. In prediction, such as for dielectric spectra, two parameters may be optimized- effective on-site Coulomb interaction parameter, \(U_{\rm eff}\), and the relaxation time, \(1/\tau \). We thus constructed a neural network to learn a relation between the parameters and the calculated dielectric spectra, and then determined the optimal values to reproduce experimental spectra. For the NiO, we obtained \(U_{\rm eff}\) of 6.1 eV and \(1/\tau \) of 0.38 eV, which are reasonably close to literature values. In the case of YIG, the results interestingly predict to two different \(U_{\rm eff}\) values, \(U_{\rm eff}^{\rm O}\) and \(U_{\rm eff}^{\rm T}\), for two inequivalent octahedral and tetrahedral Fe cation sites. The calculated spectra fairly agree with experiments. The detailed results and discussion including the methodology will be presented. Keywords: Materials Informatics, DFT+U, Dielectric Properties Share Link | Plain Format | Corresponding Author (Takahiro Matsumoto)

87	Materials Physics	ABS-93
Crystal Structure, Morphology, and Vibrational Behaviour of Co0.4Ni0.5Zn0.1Fe2O4 Magnetic Nanoparticles by Various Synthesis Temperature ASN Hidayah (a), S Zuhroh (a), NIM Aturroifah (a), NEA Wahyuni (a), Hartatiek (a,b), R Kurniawan (a,b), AA Sukkaew (c), and J Utomo (a,b)* a) Department of Physics, Faculty of Mathematics and Natural Science, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia b) Center of Advanced Materials for Renewable Energy, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia *joko.utomo.fmipa[at]um.ac.id c) Department of Renewable Energy Technology, Faculty of Science Technology and Agriculture, Yala Rajabhat University, 95000, Thailand Abstract Co0.4Ni0.5Zn0.1Fe2O4 magnetic nanoparticles have been succesfully synthesized by using the co-precipitation method with the various synthesis temperature (50, 70, 90, 110, and 130 Celcius degree) and constant concentration of NaOH. Characterization test of Co0.4Ni0.5Zn0.1Fe2O4 magnetic nanoparticles was conducted by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) to analyze particle size, crystal structure, and the morphology. From the results of XRD analysis, the diffraction pattern showed that Co0.4Ni0.5Zn0.1Fe2O4 magnetic nanoparticles had a spinel cubic crystal structure. Beside of that, the crystanility increased with the increase of synthesis temperature. The lattice parameters of Co0.4Ni0.5Zn0.1Fe2O4 magnetic nanoparticles in temperature 90 Celcius degree was 8.270 Angstrom, and there was no significant change in the lattice parameters for the all samples. Investigated by TEM, the grain size of Co0.4Ni0.5Zn0.1Fe2O4 magnetic nanoparticles at temperature 90 Celcius degree was 15.32 nm. In addition, FTIR (Fourier Transform Infra Red) characterization was conducted to determine the vibration mode of Co0.4Ni0.5Zn0.1Fe2O4 magnetic nanoparticles. The result of vibration bands in Co0.4Ni0.5Zn0.1Fe2O4 magnetic nanoparticles was the absorption peak of the octahedral site was placed at the 465.5 cm-1 , while the absorption of the tetahedral site was placed at 674.2 cm-1 Keywords: synthesis temperature, crystal structure, magnetic nanoparticles Share Link | Plain Format | Corresponding Author (Ade Siyanti Nurul Hidayah)

88	Materials Physics	ABS-100
Surface Functional Groups Effect on the Absorption Spectrum of Carbon Dots: Initial TD-DFT Study Reza Umami(a) Fitri Aulia Permatasari(a) Citra Deliana Dewi Sundari(b,c) Fahdzi Muttaqien (d,e) and Ferry Iskandar(a,e,*) (a) Department of Physics, Faculty Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, West Java 40132, Indonesia. (b)Inorganic and Physical Chemistry Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, West Java 40132, Indonesia. (c)Department of Chemistry Education, UIN Sunan Gunung Djati Bandung, Jl. Cimincrang, Bandung, West Java 40292, Indonesia. (d)Master Program in Computational Science, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia (e)Research Center for Nanoscience and Nanotechnology, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung, West Java 40132, Indonesia. Abstract Carbon dots (CDs) has attracted considerable interest due to its remarkable performance, low cost and ease of preparation, and wide range of potential applications. The surface engineering, including modifying the surface functional group and subsequent chemical modification are preferable to achieve the requirement of the specific application. Oxygen and Nitrogen-based surface functional groups are two common functionalization on CDs that subsequently generated during the synthetic process. In this study, we elucidate the optical properties of Oxygen- and Nitrogen-functionalized CDs by means of time dependent density functional theory (TD-DFT). Both considered functional groups, the carbon-oxygen double bond (-C=O) and amino groups (-NH2), are quite favourable to tailor the optical properties of CDs, especially in enhancing its absorption spectrum. Moreover, the carbonyl (-C=O) and amino (-NH2) functional groups effectively serve a new absorption peak in the first near infra-red window (650-900 nm). Our results may suggest potential application of the amino and carbonyl functionalized CDs as a photothermal agent in the photothermal cancer therapy. Keywords: absorption- Carbon dots- functional groups- TD-DFT- Share Link | Plain Format | Corresponding Author (Ferry Iskandar)

89	Materials Physics	ABS-114
Study of Phase Transformation, Structures, Morphology, and Vibration of Ni-Zn-Co Ferrites Nanoparticles due to Annealing Temperature S Zuhroh, ASN Hidayah, NIM Aturroifah, NEA Wahyuni, J Utomo* Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang No. 5, Malang, 65145, Indonesia *Corresponding author: joko.utomo.fmipa[at]um.ac.id Abstract Ni-Zn-Co ferrites nanoparticles (Ni0.4Zn0.5Co0.1Fe2O4) were synthesized by coprecipitation method and annealed at different temperatures (200, 400, 600, 800, 1000 degree celsius). Nanoparticles were characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared (FTIR) Spectroscopy to determine their structure, morphology, and vibration. Overall, all samples showed spinel cubic structures. In addition, XRD analysis showed the phase transformation from magnetite to hematite. The increase of annealing temperature leads to the larger average size of nanoparticles which were estimated by analyzing TEM images using the ImageJ software. The average diameter of nanoparticles with annealing temperature of 600 degree celsius is (10.9 plus min 0.5) nm and the average diameter of nanoparticles with annealing temperature of 1000 degree celsius is (18.6 plus min 0.4) nm. FTIR measurements between 400 - 4000 cm-1 confirmed the absorption band in the spectrum. The FTIR spectra of the nanoparticles confirmed the presence of vibration bands of metal ions which were located at octahedral and tetrahedral sites. Keywords: Ni0.4Zn0.5Co0.1Fe2O4, phase transformation, annealing temperature Share Link | Plain Format | Corresponding Author (Sayyidati Zuhroh)

90	Materials Physics	ABS-120
Energy Band Gap Lithium Tantalate (LiTaO3) Doping Niobium and Rubidium Agus Ismangil, Fatimah Noor Arifiati, Toto Winata Institut Teknologi Bandung Abstract This method has the advantage that the procedure is easy, the cost is relatively economical, and get good results. Chemical solution deposition (CSD) method is a method of making films by depositing chemical solutions on the surface of the substrate, then prepared with a spin coater at a speed of 3000 rpm for 30 seconds each drop of a LiTaO3 solution. The results show that the band gap energy LiTaO3 film shown in the picture 4 Pure LiTaO3 film, has band gap energy of 1 eV. Electrons are more easily excited than valence band to conduction band because the energy required is not too large. and Niobium-doped LiTaO3 film, having a band gap energy of 1.15 eV. Great energy is required for electrons to excited from valence band to conduction tape. Meanwhile, the rubidium doped LiTaO3 film has a band gap energy of 1.30 eV. Keywords: band gap energy, lithium tantalate, niobium, rubidium Share Link | Plain Format | Corresponding Author (Agus Ismangil)

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