
Eden StevenBoth at Emmerich Education Center and Sekolah Pelita Harapan · Research and Development
Eden Steven
Doctor of Philosophy
About
53
Publications
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Introduction
I had my Ph.D. degree in Physics with focus in Advanced Materials and Electronics at Florida State University.
I then served as an adjunct faculty at the Florida State University and as a Dean Postdoctoral Fellow at National High Magnetic Field Laboratory, where the research focused on interdisciplinary fields involving spider silk among others. My research interest is on synergistic interplay between crystalline, soft, and natural materials for environmental, energy, and electronics applications.
I currently hold positions as the Director of Research and Development at Emmerich Education Center and Director of Sekolah Pelita Harapan Applied Science Academy. My dream is to empower younger students, teachers, and the general public through hands-on science educational programs.
Additional affiliations
August 2018 - August 2018
Education
January 2007 - December 2012
January 2002 - December 2006
January 2002 - December 2006
Publications
Publications (53)
Flexible sensors made from organic bilayer films of molecular conductor on polymeric matrix have attracted many interest due to their simple fabrication with high potential for being scaled up, and for their high-performing multi-functionality at room temperatures. In particular, the piezoresistive property of the organic bilayer film is among one...
The recent surge in pharmaceutical micro-pollutants in water bodies calls for an efficient method to neutralize wastewater to sustain the ecosystem. One of the ways to degrade drug molecules is through photocatalytic degradation using UV rays. ZnO is known to be a common catalyst in the degradation of contaminants found in wastewater. However, due...
Despite the demand for clean water, it is commonly deficient. In the past two decades, there has been renewed interest in the development of clean water generation processes from atmospheric moisture. Atmospheric water generation is a two-stage process; in the first stage, the moisture is accumulated in an absorber material, and in the second stage...
We have detected a large Nernst effect in the charge density wave state of the multiband organic metal α-(BEDT-TTF)2KHg(SCN)4. We find that apart from the phonon drag effect, the energy relaxation processes that govern the electron–phonon interactions and the momentum relaxation processes that determine the mobility of the q1D charge carriers have...
We have detected a large Nernst effect in the CDW state of the multiband organic metal α−(BEDT−TT)2KHg(SCN)4. We find that there exists a significant gradient of charge relaxation processes that can generate a sizeable contribution adding especially to the transverse thermoelectric signal. Apart from the phonon drag, the energy relaxation processes...
The domestic silkworm or mulberry silk moth, B. mori L., provides more than 99% of the world’s silk. Silk, as a sericulture product, was first introduced in Indonesia through a trade mechanism and began to develop in 1953. Several factors (economic, ecological, market, and cultural) support sericulture and make it become one of the non-timber fores...
Plastic pollution is a well-known problem but very challenging to solve. A new paradigm, the circular plastics economy, has been introduced recently to address this problem. Reducing, reusing, recycling, and composting are four essential aspects of the circular plastics economy. However, most industries and societies focus solely on reducing, recyc...
In this time and age, mental health and technology plays a big role in society. The app Companion is a mental health app which targets students during their struggle in life, where they may feel there is no one to talk to and no one to reach for help. The app aims to be a safe place for students to pour their thoughts and feelings out as they consu...
Visual disabilities are a recurring issue that negatively impacts many lives. Many existing public spaces are inaccessible to blind people. Although, many studies aim at assistive technology solutions, scalability of such solutions remains a challenge. Thus, the aim of this study is to develop a scalable solution to improving the accessibility of p...
Autonomous transportation is a rapidly emerging field of technology with potential applications ranging from safe delivery of goods in disaster sites or hospitals to intelligent warehouse logistics management. However, an overwhelming majority of this emerging process focuses on high-end quality products with prices which deny entrance into the fie...
Some diagnostic tools rely on human eyesight to determine their results such as urine dipsticks or pH strips. Ideally, in these cases, human eyesight needs to be verified by other people, or technology, as misinterpretations may lead to dangerous outcomes. Hence, to alleviate this issue, in this proof-of-concept we developed a portable and compact...
Colloidal nanoalloys have been shown to have combined advantageous properties of their metallic constituents. However, the research on the electrical properties of colloidal nanoalloys is still lacking. We report an electrical properties study of gold-silver nanoalloys of various compositions suspended in Milli-Q water using impedance spectroscopy....
The interlayer magnetothermopower of the organic superconductor
k-(ET)2Cu(NCS)2 is studied at temperatures down to 0.5 K and fields up to 32 T. Analysis of the background magnetothermopower shows that at low temperatures it is negative and exhibits an upturn at higher field, producing a dip at a field close to the upper critical field Bc2. There ar...
Angular, magnetic field and temperature dependence of the interlayer Seebeck effect of the multiband organic conductor α −(BEDT −TTF)2KHg(SCN)4 is experimentally studied at temperatures down to 0.55 K and fields up to 31 T in a wide range of angles. The background magnetic field and angular component of the Seebeck effect as well as the magnetic qu...
In this work, we demonstrate and evaluate the viability of SrAl2O4 :Eu2+, Dy3+ crystals for long-term light storage applications at low temperatures that can be activated at higher temperatures for on-demand lighting applications. The switching mechanism is discussed from the point of view of the possible interplay between charge transport and the...
This work investigated the crystal structure, resistivity and specific heat of La0.41Ca0.59Mn1-xCuxO3 with x = 0.06 and 0.15. The samples were prepared by a solid reaction method and in milling with high energy milling (HEM) of 700 rpm for ten hours. Neutron scattering with high resolution powder diffraction (HRPD) is used to analyze the phase and...
We report on experimental studies of magnetic quantum oscillations of the interlayer thermopower in the charge density wave state of the multiband organic conductor α -(BEDT-TTF) 2KHg(SCN)4 . The magnetic field is along the direction perpendicular to the conducting layers. The interlayer thermopower or Seebeck effect has been measured in magnetic f...
In this article we demonstrate that a migration of iodine species and chemical transformation in a moist environment induced by a voltage-biased Pt electrode is able to alter the color and degree of charge transfer in a layer of the 2D organic molecular metal (BEDO-TTF)2.4I3 [BEDO = bis(ethylenedioxy)tetrathiafulvalene] self-assembled at the surfac...
We have successfully measured physical and magnetic properties of the La0.5Ca0.5Mn0.9Cu0.1O3 at temperature in the range of 10-100 K. Physical properties have covered electrical resistivity and specific heat. The properties, which serve as a function of temperature, were investigated by using Physics Properties Measurement System (PPMS) with and wi...
We have performed resistivity measurements as a function of temperature, with and without an external magnetic field. Magnetization measurements are also done as a function of temperature M(T) as well as a function of an external magnetic field M(H) for La0.73Ca0.27Mn1-xCuxO3 compounds with 0≤x≤0.19. The samples with x = 0 and 0.06 are insulators....
Benzoquino-bis-1,2,3-dithiazole 5 is a closed shell, antiaromatic 16π-electron zwitterion with a small HOMO-LUMO gap. Its crystal structure consists of planar ribbon-like molecular arrays packed into offset layers to generate a "brick-wall" motif with strong 2D interlayer electronic interactions. The spread of the valence and conduction bands, coup...
A critical feature of the electronic structure of oxobenzene-bridged bisdithiazolyl radicals 2 is the presence of a low-lying LUMO which, in the solid state, improves charge transport by providing additional degrees of freedom for electron transfer. The magnitude of this multiorbital effect can be fine-tuned by variations in the π-electron releasin...
The synthesis of (BEDT-TTF)2I3 in the presence of two neutral amphiphilic molecules [N-octylfurfurylimine and 1-octanamine, N-(2-thienylmethylene)] leads to single and aggregated nanoparticles of 2 to 6 nm size. The samples contain highly crystalline nanoparticles of the βCO-(BEDT-TTF)2I3 phase, confirmed by XRD. Temperature dependent resistance an...
The study of the perovskite manganites La0.47Ca0.53Mn1-xCuxO3 with x = 0, 0.06, 0.09, and 0.13 has been done. The magnetic structure was determined using high-resolution neutron scattering at room temperature and low temperature. All samples were paramagnetic at room temperature and antiferromagnetic at low temperature. Using the SQUID Quantum Desi...
The magnetic susceptibilities of nanoparticle assemblies of two Bechgaard salts (TMTSF) 2 PF 6 and (TMTSF) 2 ClO 4 , have been studied vs temperature and magnetic field. In the bulk these materials exhibit a spin density wave formation (T SDW = 12 K) and superconductivity (T c = 1.2 K), respectively. We show from inductive (susceptibility) measurem...
Co-crystallization of a cationic FeII complex with a partially charged TCNQ.δ− (7,7′,8,8′-tetracyanoquinodimethane) radical anion has afforded molecular materials that behave as narrow band-gap semiconductors, [Fe(tpma)(xbim)](X)(TCNQ)1.5⋅DMF (X=ClO4− or BF4−; tpma=tris(2-pyridylmethyl)amine, xbim=1,1′-(α,α′-o-xylyl)-2,2′-bisimidazole). Remarkably,...
Co-crystallization of a cationic FeII complex with a partially charged TCNQ.δ− (7,7′,8,8′-tetracyanoquinodimethane) radical anion has afforded molecular materials that behave as narrow band-gap semiconductors, [Fe(tpma)(xbim)](X)(TCNQ)1.5⋅DMF (X=ClO4− or BF4−; tpma=tris(2-pyridylmethyl)amine, xbim=1,1′-(α,α′-o-xylyl)-2,2′-bisimidazole). Remarkably,...
We find that the Hall effect in a single crystal of UCoGe varies as a function of the angle between the applied magnetic field and the easy magnetic axis up to fields of 18 T at 0.2 K, i.e. in the region where both superconductivity and ferromagnetic order coexist. Instead of following the conventional cos(teta) dependence the two components that...
LiH2PO4 (LDP) is a favored candidate for hydrogen fuel cells, but the mechanism of its high protonic conductivity remains unclear. A complicating factor has been the lack of resolution in the reported proton NMR spectra. We now report multinuclear magic angle spinning NMR in LDP at magnetic fields up to 21.2 T. Well-resolved 1H NMR spectra are obse...
Since their discovery, organic conductors have attracted fundamental and device physics interest due to their diverse physical properties. However, conventional electrochemical growth methods produce millimeter-sized crystals that do not translate to the fabrication of large-scale thin-film devices. Of late a chemical-vapor annealing method has bee...
(TMTSF)2PF6 and (TMTSF)2ClO4 Bechgaard salts, (BEDT-TTF)2I3, and TTF[Ni(dmit)2]2 [TMTSF = tetramethyltetraselenafulvalene; BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene; TTF = tetrathiafulvalene; dmit = 1,3-dithiole-2-thione-4,5-dithiolate] are among the most popular molecular superconductors. They are grown as nanoparticles that exhibit propert...
Understanding the compatibility between spider silk and conducting materials is essential to advance the use of spider silk in electronic applications. Spider silk is tough, but becomes soft when exposed to water. Here we report a strong affinity of amine-functionalised multi-walled carbon nanotubes for spider silk, with coating assisted by a water...
The angular dependence of the magnetothermopower of a charge transfer organic salt α-(ET)(2)KHg(SCN)(4) below (4 K) and above (9 K) the phase transition temperature, T(p) = 8 K, and under fields of 15 T and 25 T, below and above the 'kinkfield', has been studied. We find that for a longitudinal thermoelectric measurement both an interlayer thermopo...
A procedure for fabricating adhesive stamp electrodes based on gold coated adhesive tape used to measure electronic transport properties of supra-micron samples in the lateral range 10-100 μm and thickness >1 μm is described. The electrodes can be patterned with a ~4 μm separation by metal deposition through a mask using Nephila clavipes spider dra...
Naturally harvested spider silk fibers are investigated for their
physical properties under ambient, humidified, iodine-doped, pyrolized,
sputtered gold and carbon nanotube coated conditions. The functional
properties include: humidity activated conductivity; enhanced
flexibility and carbon yield of pyrolized iodized silk fibers; full
metallic cond...
The magnetic field and angle dependences of the thermopower and Nernst effect for the quasi-two dimensional (q2D) organic conductor α-(ET)2KHg(SCN)4 are measured at temperatures below (4 K) and above (9 K) the transition temperature in fields of up to 31 T. In addition, a theoretical model involving a magnetic breakdown effect between the q1D and q...
This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents...
The magnetic field and angular dependencies of the thermopower and Nernst
effect of the quasi-two-dimensional organic conductor alpha-(ET)2KHg(SCN)4 are
experimentally measured at temperatures below (4 K) and above (9 K) the
transition temperature to fields of In addition, a theoretical model which
involves a magnetic breakdown effect between the q...
The angular dependent magnetoresistance of the superconducting ferromagnet UCoGe is studied in detail at 40 mK to fields of 18 T in a single crystal sample with a low residual resistivity ratio [R( 300 K)/R(1 K) = RRR = 5]. A ferro-to-ferrimagnetic transition near 9 T that depends only on the field component along the uniaxial magnetic c axis is ob...
In our MBE-grown LaAlO3/SrTiO3 samples we find the interface to be conducting and sometimes even superconducting when the La/Al ratio is less than or equal to 0.97 ± 0.03. Here, we report on the superconducting behavior observed in some samples with La/Al ratio above 0.84 ± 0.03 and below 0.97 ± 0.03. The superconducting critical temperature is fou...
We have measured MBE-grown LaAlO3/SrTiO3 samples at temperatures ranging from room temperature to 20mK and at magnetic fields up to 18 Tesla. The La(1-x)Al(1+x)O3 films studied were grown with a stoichiometry gradient (varying x). We report on the low-temperature sheet carrier density and mobility of the conducting samples -- samples with La/Al rat...
With the interest of ground state near CDW at low temperature, the electronic properties under high pressure, at low temperature and in high magnetic field of HMTSF-TCNQ are examined. At 1.5–1.6GPa, but not at P=0, a novel hysteretic behavior irrespective of magnetic field orientation and probable quantum oscillations in a specific orientation of m...
Shubnikov–de Haas and angular dependent magnetoresistance oscillations have been used to explore the role of anion size, magnetic moment, and disorder in the organic conductors κ‐(BETS)2GaBr4κ‐(BETS)2GaBr4 and κ‐(BETS)2FeCl2Br2κ‐(BETS)2FeCl2Br2 in the isomorphic class κ‐(BETS)2Ga1‐xFexCl4‐yBryκ‐(BETS)2Ga1‐xFexCl4‐yBry. The results, combined with pr...
With the interest of ground state near CDW at low temperature, the electronic properties under high pressure, at low temperature and in high magnetic field of HMTSF-TCNQ are examined. Up to 8 GPa, the overall resistivity-temperature behaviour are unchanged, i.e. broad resistance minimum around 100–150 K and subtle resistance decrease below around 3...
Shubnikov-de Haas and angular dependent magnetoresistance oscillations have been used to explore the role of anion size, magnetic moment, and disorder in the organic conductors kappa-(BETS)_2GaBr_{4} and kappa-(BETS)_2FeCl_{2}_Br_{2} in the isomorphic class kappa-(BETS)_2Ga_{1-x}Fe_{x}Cl_{4-y}_Br_{y}. The results, combined with previous work, show...
An experimental study was conducted on the spatial distributions of hydrogen emission intensities from low-pressure plasmas generated by laser ablation of zircaloy-4 and black stone targets in nitrogen and helium ambient gases. In addition to confirming the previously observed intensity enhancement effect in ambient helium gas, the hydrogen and hel...
Dielectric relaxation is universal in characterizing polar liquids and solids, insulators, and semiconductors, and the theoretical models are well developed. However, in high magnetic fields, previously unknown aspects of dielectric relaxation can be revealed and exploited. Here, we report low temperature dielectric relaxation measurements in light...
The electrical conductivities (σ) of nanocomposites of single-walled carbon nanotubes (SWCNTs) and high density polyethylene (HDPE) have been studied for a large number of nanocomposites prepared in a SWCNT concentration range between 0.02 and 8 wt%. The values of σ obey a percolation power law with an SWCNT concentration threshold, pc = 0.13 wt%,...
We present a study of the behavior of the 1-D organic conductor, (TMTSF)2PF6, under electric field. We observed a dependence of the conductivity, critical temperature (at which the spin density wave effect occurs, TSDW), and magnetoresistance with the applied electric field. The conductance of the sample in the low temperature range (less than TSDW...