D. Darminto

• Doctor
• Professor (Full) at Sepuluh Nopember Institute of Technology

Biomass is one of the attractive, renewable, widely available, and cost-effective precursors to obtain carbon. In this work, the carbon-based material derived from coconut shell was produced by carbonization method that is applicable for anode materials especially dual-carbon sodium-ion batteries. The as-synthesized coconut shell was burned to be a...

Silica/zinc ferrite nanocomposite was prepared using the coprecipitation method to be applied as a candidate for drug delivery agents. The success of nanocomposite synthesis was evidenced by the presence of an amorphous silica phase and zinc ferrite phase in the X-ray diffraction pattern. In addition, in the FTIR characterization, the main function...

Palm kernel shell (PKS), a renewable biomass waste product of the palm oil industry, offers significant potential for use as a carbon-based anode material in dual carbon batteries (DCBs). This study investigates the structural properties of PKSC after several treatments by varying the temperature. The PKSC samples were analysed using Scanning Elect...

This study examines how methane flow rate during the plasma-enhanced chemical vapor deposition (PECVD) process affects the electronic properties of amorphous silicon-carbon (a-SiC) thin films. The films were deposited with varying methane flow rates, and their structural and electronic properties were analyzed using spectroscopic ellipsometry and a...

This research reveals the application of electrochemical impedance spectroscopy (EIS) in analyzing and improving the performance of hydrogenated amorphous silicon (a-Si: H) based photovoltaic cells. As a non-destructive technique, EIS provides deep insight into the electrochemical characteristics of photovoltaic cells, including series resistance,...

This study investigated the influence of Ca2+ ion vacancies on the structural, magnetic, and magnetocaloric properties of La0.7Ca0.2-x□xSr0.1MnO3 (x = 0.00, 0.05, and 0.10) synthesized by the solid-state reaction method. Structural analysis revealed a single-phase orthorhombic crystal structure with the Pnma space group for most samples, except for...

This study employed molecular dynamics simulations utilizing the ReaxFF force field to elucidate the mechanisms underlying methane decomposition and hydrogen generation on nickel clusters (Ni37, Ni55, and Ni80). The transformation of methane into valuable products, including carbon species and hydrogen molecules, is of considerable significance owi...

Carbon fibers from polyvinyl alcohol (PVA) was achieved by the electrospinning technique, which was subsequently followed by the stabilization and carbonization of electrospun PVA fibers. The XRD pattern of PVA fiber confirms the change in the structure of PVA nanofibers and carbonized PVA from temperatures of 200, 300, 400, 500, and 700 °C, result...

This research aims to improve the performance of a-Si: H solar cells, particularly in terms of carrier transport properties, through a numerical design approach utilizing AFORS-HET simulation software. By performing a series of rigorous computer simulations, we explore the potential regulation of the intrinsic layer thickness, carrier mobility, loa...

Using catalytic methane decomposition techniques to produce H2 could advance renewable energy development. Selecting the proper catalyst for this method is essential for efficient hydrogen production. We used reactive molecular simulations to examine methane's decomposition reaction and the formation of H2 molecules on a Ni (1 1 0) surface. The res...

Abstrak Indonesia salah satu negara terdampak Coronavirus disease 2019, sejak saat itu telah diterapkan pembelajaran daring interaktif dengan memanfaatkan beberapa platform seperti Google Classroom, dan Zoom. Saat ini guru dituntut untuk menyiapkan metode pembelajaran tatap muka yang tidak monoton dan handal dalam penguasaan teknologi serta dapat m...

This research reveals the application of electrochemical impedance spectroscopy (EIS) in analyzing and improving the performance of hydrogenated amorphous silicon (a-Si: H) based photovoltaic cells. As a non-destructive technique, EIS provides deep insight into the electrochemical characteristics of photovoltaic cells, including series resistance,...

As a 2D material continuously being researched, h-BN is a unique material with the potential to develop its applications. Basically, h-BN is an insulating and non-magnetic material. However, in its development, this material can become a candidate in the fields of energy to optoelectronic devices. This can be achieved by modifying the h-BN structur...

As a material that has been widely researched, graphene is certainly interesting because it has many unique features. In its development, graphene is very promising as an optoelectronic material. However, in theory, graphene has obstacles in its development because its band gap position is zero. With various modifications in opening the band gap so...

h-BN is a 2D material which also has considerable development potential in several fields. 2D materials such as h-BN are basically insulating materials but have unique properties and it would be good if they could be developed, especially to meet future energy needs or in the development of electronic devices. Therefore, the properties of h-BN are...

Poster presentation at the BERA Conference and WERA Focal Meeting 2024, University of Manchester, 9-12 September 2024.

Teeth bleaching techniques generally use high concentrations of bleaching agents such as H2O2, which can harm dental health. Therefore, an alternative method is needed to minimize the use of H2O2. The aim of this study was to determine the characteristics and effectiveness of a teeth-whitening gel made from polydopamine and chitosan-modified TiO2....

Recently, abaca fibers have become the focus of specialized research due to their intriguing characteristics, with their outstanding mechanical properties being a particularly notable. In the conducted study, the abaca fibers underwent a preliminary treatment process involving an alkaline solution, which was composed of 0.5% sodium hydroxide (NaOH)...

Demand for battery and supercapacitor materials rapidly increases as energy storage deployments accelerate. Waste-based supercapacitors have become a point of interest to accommodate growing demand and awareness of environmentally friendly products. This work aims to examine how doping with sulfur and nitrogen affects the morphology and structure o...

Kegiatan pengabdian kepada masyarakat ini dilakukan dalam rangka membantu meningkatkan efisiensi pertanian jagung petani poktan LMPSDH Wonodadi di lahan Hutan Wonodadi, Lembeyan, Magetan yang selama ini umumnya masih menggunakan cara tradisional sehingga kurang efisien dari segi tenaga, waktu dan biaya. Kegiatan dilakukan dengan merancang mesin ter...

In the pursuit of a clean and environmentally friendly future, magnetic refrigerator technology based on the magnetocaloric effect has been proposed as a replacement for conventional refrigeration technologies characterized by inefficient energy use, greenhouse gas emissions, and ozone depletion. This paper presents an in-depth exploration of the c...

Mouthwash is an alternative to address problems in the oral cavity, such as caries, periodontal inflammation, and microbial abscesses generally caused by pathogens. However, chlorhexidine contained in the mouthwash was limited concentration, i.e., 0.2 %, due to the side effects caused by these ingredients. Even though chlorhexidine has bactericidal...

Numerous researchers in the energy field are engaged in a competitive race to advance hydrogen as a clean and environmentally friendly fuel. Studies have been conducted on the different aspects of hydrogen, including its production, storage, transportation and utilization. The catalytic methane decomposition technique for hydrogen production is an...

Dolomite is a type of sedimentary rock material that is often found in the Bangkalan Madura area. This dolomite has a higher MgO compound content than in the other areas, namely 40 %, but its utilization has only been as fertilizer and building materials. For this reason, this research aims to determine the characteristics of MgO nanoparticles and...

The implementation of water-chitosan slurry is needed to achieve better battery, in terms of enviromentally friendly and cheapest cost. In this research, sodium-ion cathode batteries based on sodium iron phosphate and the water-chitosan slurry were successfully synthesized with the sol-gel method. The result of the X-Ray Diffraction (XRD) test conf...

Encouraged by the tremendous success of lithium iron phosphate (LiFePO4), analogous NaFePO4 has been predicted to show identical properties as LiFePO4. Synthesis of NaFePO4 materials in the maricite phase has been carried out using the sol-gel method with variations of calcination temperature and starting materials as sources of sodium Na2CO3 and N...

We have successfully synthesized ZnFe2O4/SiO2—Morus alba L. nanoparticles as a drug delivery agent. The nanostructural and optical properties of ZnFe2O4/SiO2—Morus alba L. were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy–energy dispersive X-ray (SEM–EDX) spectroscopy, transmi...

This paper reports on the characterization of Sn- and Al-doped zinc oxide thin film for potential ammonia gas detection. The sol–gel method has been used to deposit the dopant onto the glass substrate at an annealing temperature of 500°C for three different doping concentrations, which are 0.5, 1.0, and 1.5 at.%. The method used to produce this thi...

Silicon nanowires can improve broadband optical absorption and reduce the radial carrier collection distance in solar cell devices. The disordered nanowire arrays grown by the Plasma-Enhanced Chemical Vapor Deposition method are attractive because they can be embedded on low-cost substrates such as glass, and are compatible with large areas. Here,...

Pada studi ini, telah dilakukkan pembuatan lapisan sel surya silikon amorf terhidrogenasi (a-Si:H) tipe p dengan menggunakan sistem PECVD pada subtrat kaca ITO. Deposisi yang dilakukan selama 30 menit dengan daya RF 3-Watt dan temperatur 2700C. Fabrikasi sel surya amorf menggunakanmetode ekperimen dengan mengalirkan gas silan (SiH4) 20 sccm dengan...

Silica-based methyltrimethoxysilane (MTMS) offers unique properties as an alternative material for hydrophobic surfaces. In this study, SiO2 obtained through the MTMS precursor with various concentrations of cetyltrimethylammonium bromide (CTAB) 0.75 wt%, 1.5 wt%, and 2.25 wt% were prepared by sol-gel method to modify and improve a hydrophobic surf...

SiO2 were successfully synthesized by sol–gel process via in-situ modification. The SiO2 consists of two kinds of co-precursor namely raw material from quartz sand and methyltrimethoxysilane (MTMS) as main SiO2 source. By introducing SiO2 with different sizes of particle micro-submicron scale, it was suggested to construct hierarchical structure. T...

Porang (Amorphophallus muelleri Blume), a plant belonging to the Araceae family, has the main content of glucomannan and calcium oxalate which is quite high. This study aims to determine the characteristic values of glucomannan and calcium oxalate content from porang flour so that it can be used for various applications, especially hydrogel. The ch...

This study develops an absorber containing abaca fiber (Musa Textiles) and epoxy resin as a binder. The ability to absorb sound energy is related to the pore’s size present in the absorber. One of the methods to create porosity is to vary the length of fiber, which is 1, 10 mm, 15 mm and 20 mm. Before the fiber is cut to be certain length, it is tr...

This research was conducted to determine the morphology, dimensions, and structure of carbon-nanofibers, using polyvinyl alcohol (PVA) as a source of polymer fibers fabricated by electrospinning technique, and given variations in carbonization temperature. Variations in temperature during the carbonization process are carried out to see changes in...

NaFePO4, which is analogue to LiFePO4, has been expected to show similar properties as LiFePO4 that has a good cycle stability and excellent electrochemical performances. Here we report the synthesis of NaFePO4 via sol-gel method and the structural study of NaFePO4 as a cathode material for sodium-ion battery (SIB). The as-synthesized NaFePO4 sampl...

The a-C/a-C:B homojunction of palmyra sugar has been successfully fabricated using the nanospray method. Palmyra sugar was chosen as the main source of carbon because it is cheap, renewable, abundant and available around the clock. nanospray is used as a deposition method on glass ITO substrates because of several advantages, namely cheap, easy, po...

Graphenic carbon (GC) has been successfully synthesized from biomass (coconut shell charcoal) using the liquid phase exfoliation method. The dopants, in the form of light atoms such as boron (B-GC), were introduced with the aim of improving their magnetic properties. X-ray diffraction was used to identify the GC and B-GC, and the results show broad...

Graphenic carbon (GC) provides a potential ability as photovoltaic material due to its tunable properties. Here, we investigate the optical energy gap and the thickness of B-GC material as a p-type in solar cell application. The GC was prepared from old charcoal powders of coconut shells by heating process at 400°C and B-GC powders were prepared by...

Graphene-based materials have been widely developed in various applications, both in electronics and optoelectronics. It is because of their attractive characteristics, such as flexible structure, large surface area, and excellent thermal, mechanical, and optoelectronic properties. In this research, the optical absorbance of coconut shell-based car...

The presence of N-dopant in Reduced Graphene Oxide has contributed to the change of their optical band gap. In this research, this mechanism has been implemented to synthesize nitrogen-doped graphenic carbon (NGC) proposed as an n-type semiconducting layer. The graphenic-based carbon (GC) was derived from coconut shells by a green synthesis method....

Muon-spin relaxation (μSR) spectroscopy has let an understanding of the hydrogen interactions with graphene, providing insights for hydrogen storage technologies based on graphene-based compounds. We report an μSR study on the reduced graphene oxide (rGO, a product of ®Graphenea) at 300 K. Spontaneous muon-spin precession is not observed under the...

The purpose of this research is to study the interrelation between Urbach energy (Eu), optical band gap energy (Eg), and complex dielectric constant (ε) in relation to the disorder induced properties of SiO2/rGO thin films. The rGO-like carbon was created by annealing coconut shell carbon (csc) at different temperatures of 400°C, 600 oC, and 800 oC...

In this study, the use of the Fourier synthesis and the so-called Maximum Entropy Method (MEM) are evaluated in order to reveal the crystalline defect of the T’-type structure of one of 214 cuprate system, namely Pr2-xCexCuO4 (PCCO) powders. In the low-level density, the MEM calculations give a clear picture of the scattering and can eliminate the...

Carbon compounds based on natural materials continue to be studied and developed to produce graphene compounds that are effective and suitable for specific applications. This study reports the effect of heating (400, 600, 800, and 1000 °C) on the optical properties and defects of rGO-like carbon derived from the biomass of coconut shells. The resul...

The search for materials for next-generation spintronic applications has witnessed exponentially increasing interest, mainly due to the explosive development of numerous two-dimensional (2D) materials discovered in the last decade. Among them, MXenes have emerged as promising candidates for many applications due to their unique and versatile tunabi...

LiFePO4-Silicon doped has been widely developed as a battery cathode material. Due to the doping of silicon atoms, this study aims to determine the peak energy (E0), oxidation state and percentage of component composition for Fe K-edge. The experimental sample used are LFP Si-0%, LFP Si-1%, LFP Si-3% and LFP Si-6%. These samples were characterized...

The optical energy gap of the semiconducting intrinsic layer plays a crucial role in determining the increase in efficiency. The carbon-based biomass can be a choice for the silicon used as solar cell material. Here, we proposed the best biomass that can be used as a semiconductor component in solar cell applications. Coconut shells as bio-waste an...

Many research initiatives are now dedicated to efficient methods of COx-free H2 production. In this study, we investigated the process of CH4 molecule dissociation on a Pt (100) surface using ReaxFF-based molecular dynamics simulations. On the Pt (100) surface, we observed that H atoms dissociated one by one from the CH4 molecule. The C atoms then...

Amorphous carbon (a-C) has become a promising material applied for optoelectronic devices. The requirement parameter that should be considered to develop the device is the electronic property of the structure composed. a-C materials are composed of a hybridization mixture of sp2 and sp3 orbitals. The new characteristic possessed by a-C must be stud...

An understanding on roles of excitons and plasmons is important in excitonic solar cells and photovoltaic (PV) technologies. Here, we produce new amorphous carbon (a-C) like films on Indium Tin Oxide (ITO) generating PV cells with efficiency three order of magnitude higher than the existing biomass-derived a-C. The amorphous carbon films are prepar...

In this work, we report that hydrogen (H 2) doped in n-type a-Si:H thin films strongly influences the electronic correlation in increasing the conversion output power of solar cells. Type n a-Si:H thin films were grown using PECVD on ITO substrates with various H2-doping, to obtain various thin films for solar-cell applications. N-type a-Si:H thin...

This study aims to identify and analyze the band gap width of the carbon phase produced from corncobs mixed with PEG-4000 to see the surface area of the corncob carbon phase. First, the characterization test was carried out using Scanning Electron Microscope Energy-Dispersive X-ray (SEM-EDX) spectroscopy to determine the morphology and Ultraviolet-...

This book (written in Bahasa Indonesia) provides an introduction and basic knowledge on the phenomena of superconductivity, superconducting materials, developmental aspects of the theory and an overview of its potential applications.

In this study, we investigated the structural alterations that occur when Ti-based alloys, namely, Tix%Al(100-x)% and Tix%Ni(100-x)%, are subjected to compressive and tensile loading using molecular dynamics simulations. It is found that the Tix%Al(100-x)% and Tix%Ni(100-x)% alloys containing equal ratios (50:50) of the atoms have a higher mechanic...

Hydrogenated amorphous silicon (a-Si: H) has received great attention for rich fundamental physics and potentially inexpensive solar cells. Here, we observe new resonant excitons and correlated plasmons tunable via hydrogen content in a-Si: H films on Indium Tin Oxide (ITO) substrate. Spectroscopic ellipsometry supported with High Resolution-Transm...

Chemical modifications for waste oil palm trunks had carried out as acoustic material. This modification was conducted in two stages. Firstly, formalization with formaldehyde solution and secondly is impregnation with melamine-formaldehyde resin. Formalization was conducted in alkaline condition (pH 10) for 3 days and 5 days. Impregnation was carri...

Pada umumnya pelajaran fisika dianggap sebagai pelajaran yang tidak mudah oleh kebanyakan siswa. Walaupun sebagaimana kita ketahui pemanfaatan ilmu fisika sangat banyak dalam kehidupan nyata. Salah satunya penggunaan arang batok kelapa sebagai media filter air. Salah satu tujuan kegiatan abdimas ini agar siswa mampu dan memahami pengaplikasian pela...

In this study, we report the application of a functional dielectric model of scalable ellipsometric spectroscopy to investigate the optical response of materials in the optical spectrum modeling of hydrogenated amorphous silicon. ES is used to obtain the dielectric constant of the data fitting experimental. Then ψ and Δ are obtained from the analys...

In this study, we report an enhancement in the efficiency of a-Si:H solar cells due to the addition of an intrinsic layer. The intrinsic layer of a-Si:H p-i1-i2-n solar cells was measured by focused beam-mapping spectroscopy ellipsometry for photon energy from 0.6 to 6.5 eV. The intrinsic a-Si:H layer was made from SiH4 and H2 by the plasma enhance...

In this study, the front work function WFITO and absorber layer bandgap’s influences on two solar cells structure performances, namely ITO/(p)a-Si:H/(i)a-Si:H/(n)a-Si:H/metal (single intrinsic, Sint) structure and ITO/(p)a-Si:H/(i1)a-Si:H/(i2)a-Si:H/(n)a-Si:H/metal (double intrinsic, Dint) structure, fabricated using RF-PECVD method were simulated,...

Ti-based alloys have the potential to be used as hydrogen storage units, including NiTi. In contrast, NiTi alloy is sensitive to H atoms. It has been found that hydrogen can cause embrittlement in NiTi alloys. Thus, it is become indispensable to elucidate the reaction of H2 molecules on the NiTi surface. Using density functional theory, we investig...

Purpose This review aims to give an overview about zinc oxide (ZnO) based gas sensors and the role of doping in enhancing the gas sensing properties. Gas sensors based on ZnO thin film are preferred for sensing applications because of their modifiable surface morphology, very large surface-to-volume ratio and superior stability due to better crysta...

MgB2/CNT is a promising candidate for superconducting wire application due to its excellent mechanical properties and carbon nanotube’s low density. However, strong interfacial adhesion between the CNT reinforcement and the MgB2 matrix is difficult to manage. Therefore, this study examines the synthesis and characterization of magnesium diboride (M...

Structural analysis and observation of the oxygen migration of Pr2-xCexCuO4 (PCCO) with Ce-doping concentration, x, of 0 and 0.15 powders are briefly studied through neutron diffraction (ND) patterns and x-ray absorption spectroscopy (XAS) spectrum in the extended x-ray absorption fine structure (EXAFS) range. The PCCO powders are synthesized using...

Nickel Titanium (NiTi) alloys are produced by heating raw Ni and Ti in high temperature. In this stage, Ni and Ti atoms diffuse and mix to form an alloy. Despite the importance of technology, Ni and Ti atoms’ diffusion mechanism, however, still remains unelucidated. We performed molecular dynamics simulations for 1 ns to investigate the diffusion p...

In this work, the imbalances in band gap energy between p-window layer and intrinsic layer (p/i interface) in p-i-n type solar cells to suppress charge recombination adopting with the addition of buffer layer, at p/i interface, namely solar cell structures without buffer (Cell A) and with buffer (Cell B). Using well-practiced AFORS-HET software, pe...

In this study, the effect of heating temperature on the structure of graphenic-based carbon (GC) has been successfully investigated. A series of GC materials was prepared from coconut shells by a green synthesis method. The process includes heating at four temperatures (T = 400, 600, 800 and 1000 °C) followed by an exfoliation process assisted by h...