Plasmonic Effect of Gold Nanostars in Highly Efficient Organic and Perovskite Solar Cells

Ginting, Riski Titian,Kaur, Sandeep,Lim, Dong-Kwon,Kim, Jung-Mu,Lee, Joong Hee,Lee, Seung Hee,Kang, Jae-Wook American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.41

<P>Herein, a novel strategy is presented for enhancing light absorption by incorporating gold nanostars (Au NSs) into. both the active layer of organic solar cells (OSCs) and the rear-contact hole transport layer of perovskite solar cells (PSCs). We demonstrate that the power conversion efficiencies of OSCs and PSCs with embedded, Au NSs are improved by 6 and 14%, respectively. We find that pegylated Au NSs are greatly dispersable in a chlorobenzene solvent, which enabled complete blending of Au NSs with the active layer. The plasmonic contributions and accelerated charge transfer are believed to improve the short-circuit current density and the fill factor. This study demonstrates the roles of plasmonic nanoparticles in the improved optical absorption, where the improvement in OSCs was attributed to surface plasmon resonance (SPR) and in PSCs was attributed to-both SPR and the backscattering effect. Additionally, devices including Au NSs exhibited a better charge separation/transfer, reduced charge recombination rate, and: efficient charge transport. This work provides a comprehensive understanding of the roles of plasmonic Au NS particles in OSCs and PSCs, including an insightful approach for the further development of high-performance optoelectronic devices.</P>

Optimal Portfolio Models for an Inefficient Market

GINTING, Josep,GINTING, Neshia Wilhelmina,PUTRI, Leonita,NIDAR, Sulaeman Rahman Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

This research attempts to formulate a new mean-risk model to replace the Markowitz mean-variance model by altering the risk measurement using ARCH variance instead of the original variance. In building the portfolio, samples used are closing prices of Indonesia Composite Stock Index and Indonesia Composite Bonds Index from 2013 to 2018. This study is a qualitative study using secondary data from the Indonesia Stock Exchange and Indonesia Bonds Pricing Agency. This research found that Markowitz's model is still superior when utilized in daily data, while the mean-ARCH model is appropriate with wider gap data like monthly observation. The Historical return has also proven to be more appropriate as a benchmark in selecting an optimal portfolio rather than a risk-free rate in an inefficient market. Therefore Mean-ARCH is more appropriate when utilized under data that have a wider gap between the period. The research findings show that the portfolio combination produced is inefficient due to the market inefficiency indicated by the meager return of the stock, while bears notable standard deviation. Therefore, the researcher of this study proposed to replace the risk-free rate as a benchmark with the historical return. The Historical return proved to be more realistic than the risk-free rate in inefficient market conditions.

A novel design of hybrid transparent electrodes for high performance and ultra-flexible bifunctional electrochromic-supercapacitors

Ginting, Riski Titian,Ovhal, Manoj Mayaji,Kang, Jae-Wook Elsevier 2018 Nano energy Vol.53 No.-

<P><B>Abstract</B></P> <P>In this study, a simple and cost-effective method of fabricating hybrid transparent conductive electrodes (TCEs) based on embedded silver nanowires (Ag NWs)/PEDOT: PSS was developed with the addition of low-temperature synthesis of Ni(OH)<SUB>2</SUB> and polyethylenimine ethoxylated (PEIE) composites as a novel interlayer. The hybrid TCEs with a Ni(OH)<SUB>2</SUB>-PEIE interlayer exhibit remarkable volumetric capacitance of 443 F cm<SUP>−3</SUP> with transparency of 86%, which is one of the highest values reported to date in the transparent supercapacitor. The fabricated bifunctional solid-state electrochromic-supercapacitor device with a transparency of 80% shows stable cyclic stability up to 10,000 charge/discharge cycles, extremely high coloration efficiency of 517 cm<SUP>2</SUP> C<SUP>−1</SUP> at 633 nm, and a fast switching speed (<0.6 s). The noted improvement is mainly caused by the Ni(OH)<SUB>2</SUB>-PEIE interlayer influence the pore density of PEDOT: PSS which provides high surface area, thus resulting in efficient charge transfer pathways and fast ion diffusion. Moreover, a capacitance retention of 90% is achieved even after 8000 bending cycles at a bending radius of 1 mm and 15 times of crumpling is tolerated without noticeable degradation, implying excellent mechanical robustness and flexibility. The results present the significant potential of transparent hybrid electrodes for efficient energy storage and electrochromicity with stable transmittance changes, even during fast charge/discharge processes, demonstrating their potential as smart wearable energy storage devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The bifunctional solid-state electromic-supercapacitor device showed a reversible electrochromic effect during charge/discharge cycles. </LI> <LI> High coloration efficiency of 517 cm<SUP>2</SUP> C<SUP>−1</SUP> at 633 nm, and fast switching speed (<0.6 s). </LI> <LI> High areal capacitance of 3.3 mF cm<SUP>−2</SUP> and excellent cyclic stability with a device transparency of 80%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Enhancement of thermoelectric performance <i>via</i> weak disordering of topological crystalline insulators and band convergence by Se alloying in Pb_0.5Sn_0.5Te_{1 − x}Se_x

Ginting, Dianta,Lin, Chan-Chieh,Kim, Gareoung,Yun, Jae Hyun,Yu, Byung-Kyu,Kim, Sung-Jin,Ahn, Kyunghan,Rhyee, Jong-Soo The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.14

<P>Topological crystal insulators (TCIs) that have an even number of topologically protected Dirac bands driven by crystalline mirror symmetry have attracted much attention in condensed matter physics. Here, we demonstrate that a weak disordering in the topological crystalline state can enhance thermoelectric performance significantly due to highly dispersive band dispersion and high band degeneracy which guarantee high electrical mobility and a high Seebeck coefficient, respectively. When we perturb a crystalline mirror symmetry by Se-doping in TCI Pb0.5Sn0.5Te1 − xSex, the topological state becomes weak so that it eventually evolves the normal state. We experimentally prove the topological phase transition concerning Se concentration by X-ray Absorption Spectroscopy (XAS) and extended X-ray absorption Fine Structure (EXAFS) analysis. Small crystalline perturbation by Se doping (<I>x</I> = 0.05) significantly enhances thermoelectric performance due to the simultaneous enhancement of electrical conductivity and the Seebeck coefficient. Therefore, we report an exceptionally high <I>ZT</I> value of 1.9 at 800 K for the <I>x</I> = 0.05 compound which is a 313% enhancement of <I>ZT</I> compared with the pristine compound. This research proposes a new strategy for exploring high-performance thermoelectric materials by weak disordering of topological crystalline Dirac semimetals.</P>

Modeling Fashion Brand Authenticity Toward Brand Usage Intention: Evidence from Indonesia

GINTING, Magdalena L.,SIHOMBING, Sabrina O.,ANTONIO, Ferdi,PRAMONO, Rudy Korea Distribution Science Association 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.6

The growth of local fashion brands in Indonesia is interesting because of the speed with which new designs are made, many variants are created, and local brands are developed. However, when it comes to buying local fashion products, the brand isn't the sole consideration. As a result, the marketing effectiveness of local fashion brands needs to be examined more thoroughly. The purpose of this study was to understand more about brand authenticity and how it affects brand usage intentions. The unit of analysis in this study was Generation Z, who purchase from local fashion companies online. A quantitative research methodology was used. The data was analyzed using the PLS-SEM method to test the hypotheses with the dependent variables. The variables were the intention of using the brand, the quality of the brand relationship, and the authenticity of the brand. The results of this study indicated that brand authenticity had an effect on brand usage intent and brand relations quality mediates the positive effect of brand authenticity on brand usage intent.

High thermoelectric performance in pseudo quaternary compounds of (PbTe)_0.95−x(PbSe)_x(PbS)_0.05 by simultaneous band convergence and nano precipitation

Ginting, Dianta,Lin, Chan-Chieh,Lydia, R.,So, Hyeon Seob,Lee, Hosun,Hwang, Junpil,Kim, Woochul,Al Rahal Al Orabi, Rabih,Rhyee, Jong-Soo Elsevier 2017 Acta materialia Vol.131 No.-

<P>Lead chalcogenides have long been studied as promising thermoelectric materials, operating at the mid temperature range of 500-950 K. Here, we studied thermoelectric properties of pseudo-quaternary compounds of (PbTe)(0.95-x)(PbSe)(x)(PbS)(0.05) (x = 0.0, 0.05, 0.10, 0.15, 0.20, 035, and 0.95) with 1% Nadoping, synthesized by melting and rapid quenching of pristine compounds of PbTe, PbSe, and PbS and followed by hot press sintering. The lattice parameters and transmission electron microscopy confirmed that the PbSe makes solid solution with PbTe leading to PbTe1-xSex matrix while the PbS precipitates in the matrix. In terms of two valence bands model, the energy band gap between conduction and valence L-band was decreased and the energy difference between L-and E-bands was increased with increasing Se concentration. The band convergence at high temperature may be associated with the enhancement of power factor. The PbS nano-scale precipitation in the matrix attributed to the decrease of lattice thermal conductivity. From the Matthiessen's rule, the lattice thermal conductivity was described by the nano precipitation as well as alloy scattering of phonons. The simultaneous emergence of band convergence and nano-precipitation in the quaternary compounds of (PbTe)(0.95-X)(PbSe)(x)(PbS)(0.05) gives rise to exceptionally high zT value of 23 at 800 K for x = 0.20. The high zT value also showed enhancement of practical thermoelectric performances such as engineering zT(eng), device efficiency eta, output power density P-d, and device zT(d). In addition, high zT compounds have good compatibility with the n-type I-doped PbTe compound, which can be applied to practical waste heat power generation. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</P>

High thermoelectric performance due to nano-inclusions and randomly distributed interface potentials in N-type (PbTe0.93−xSe0.07Clx)0.93(PbS)0.07composites

Ginting, Dianta,Lin, Chan-Chieh,Rathnam, Lydia,Yun, Jae Hyun,Yu, Byung-Kyu,Kim, Sung-Jin,Rhyee, Jong-Soo Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.26

<P>In a composite of two dissimilar or homologous semiconductors with different energy band gaps or metal/semiconductor composites, we expect a band bending effect at the interfaces. The band bending effect induced by the different Fermi levels of two compounds can selectively scatter carriers due to energy-dependent scattering time, resulting in enhancement of the Seebeck coefficient. In addition, nano-inclusions in a matrix will effectively scatter phonons. Here, we demonstrate the effects of electron and phonon scattering by nano-inclusions in n-type (PbTe0.93−xSe0.07Clx)0.93(PbS)0.07(<I>x</I>= 0.0005, 0.01, 0.1 and 0.2) composites. In the matrix, the nano-inclusions increased the Seebeck coefficient while reducing lattice thermal conductivity in (PbTe0.93−xSe0.07Clx)0.93(PbS)0.07. The chlorine doping increases the Fermi level to the bottom of the conduction band giving rise to increased electron concentration. The simultaneous emergence of the high Seebeck coefficient and low thermal conductivity resulted in the exceptional<I>ZT</I>value of 1.52 at 700 K for low chlorine doping (<I>x</I>= 0.0005), which is a very high value in n-type thermoelectric materials. The randomly distributed interface potential, induced by Fermi level tuning, with nano-inclusions is a new criterion for investigating thermoelectric properties.</P>

Enhancement of Thermoelectric Performance in Na-Doped Pb_0.6Sn_0.4Te_{0.95-<i>x</i>}Se_<i>x</i>S_0.05 via Breaking the Inversion Symmetry, Band Convergence, and Nanostructuring by Multiple Elements Doping

Ginting, Dianta,Lin, Chan-Chieh,Rathnam, Lydia,Kim, Gareoung,Yun, Jae Hyun,So, Hyeon Seob,Lee, Hosun,Yu, Byung-Kyu,Kim, Sung-Jin,Ahn, Kyunghan,Rhyee, Jong-Soo American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.14

<P>Topological insulators have attracted much interest in topological states of matter featuring unusual electrical conduction behaviors. It has been recently reported that a topological crystalline insulator could exhibit a high thermoelectric performance by breaking its crystal symmetry via chemical doping. Here, we investigate the multiple effects of Na, Se, and S alloying on thermoelectric properties of a topological crystalline insulator Pb<SUB>0.6</SUB>Sn<SUB>0.4</SUB>Te. The Na doping is known to be effective for breaking the crystalline mirror symmetry of Pb<SUB>0.6</SUB>Sn<SUB>0.4</SUB>Te. We demonstrate that simultaneous emergence of band convergence by Se alloying and nanostructuring by S doping enhance the power factor and decrease lattice thermal conductivity, respectively. Remarkably, the high power factor of 22.3 μW cm<SUP>-1</SUP> K<SUP>-2</SUP> at 800 K is achieved for Na 1%-doped Pb<SUB>0.6</SUB>Sn<SUB>0.4</SUB>Te<SUB>0.90</SUB>Se<SUB>0.05</SUB>S<SUB>0.05</SUB> mainly due to a relatively high Seebeck coefficient via band convergence by Se alloying as well as the suppression of bipolar conduction at high temperatures by the increase of energy band gap. Furthermore, the lattice thermal conductivity is significantly suppressed by PbS nanoprecipitates without deteriorating the hole carrier mobility, ranging from 0.80 W m<SUP>-1</SUP> K<SUP>-1</SUP> for Pb<SUB>0.6</SUB>Sn<SUB>0.4</SUB>Te to 0.17 W m<SUP>-1</SUP> K<SUP>-1</SUP> at 300 K for Pb<SUB>0.6</SUB>Sn<SUB>0.4</SUB>Te<SUB>0.85</SUB>Se<SUB>0.10</SUB>S<SUB>0.05</SUB>. As a result, the synergistically combined effects of breaking the crystalline mirror symmetry of topological crystalline insulator, band convergence, and nanostructuring for Pb<SUB>0.6</SUB>Sn<SUB>0.4</SUB>Te<SUB>0.95-<I>x</I></SUB>Se<SUB><I>x</I></SUB>S<SUB>0.05</SUB> (<I>x</I> = 0, 0.05, 0.1, 0.2, and 0.95) give rise to an impressively high <I>ZT</I> of 1.59 at 800 K for <I>x</I> = 0.05. We suggest that the multiple doping in topological crystalline insulators is effective for improving the thermoelectric performance.</P> [FIG OMISSION]</BR>

A Simple Approach Low-Temperature Solution Process for Preparation of Bismuth-Doped ZnO Nanorods and Its Application in Hybrid Solar Cells

Ginting, Riski Titian,Lee, Hock Beng,Tan, Sin Tee,Tan, Chun Hui,Jumali, Mohd. Hafizuddin Hj.,Yap, Chi Chin,Kang, Jae-Wook,Yahaya, Muhammad American Chemical Society 2016 The Journal of Physical Chemistry Part C Vol.120 No.1

<P>A simple low-temperature solution processed bismuth-doped ZnO nanorods (NRs) and poly(3-hexylthiophene) (P3HT) were used as electron acceptor and donor, respectively, in a hybrid inorganic-organic photovoltaic system. Controlling Bi precursor concentration via solution processing (hydrothermal method) plays an important role in altering the morphology, structure, and intrinsic defects of ZnO NRs. Interstitial doping of BiBi2O3 into ZnO (BiZO) NRs results in simultaneous improvement of the open circuit voltage and short circuit current density primarily due to prolonged charge carrier recombination lifetime, increased donor-acceptor interfacial areas with efficient exciton dissociation, and charge carrier mobility. As a result, the power conversion efficiency of the 2 wt % BiZO NRs-P3HT device was significantly enhanced by 55% compared with that of the pristine device. Overall, our study highlighted the immense potential of BiZO NRs as an excellent electron acceptor for fabrication of hybrid optoelectronic devices.</P>

Critical Behavior in Double-Exchange Ferromagnets <tex> ${\hbox{Nd}}_{0.5}{\hbox{Sr}}_{0.5}{\hbox{Mn}}_{1 \hbox{-} x}{\hbox{Co}}_{x}{{\hbox{O}}_3}$</tex>

Ginting, D.,Nanto, D.,Yu, S. C.,Phan, T. L. IEEE 2014 IEEE transactions on magnetics Vol.50 No.1

<P>The critical behavior around the paramagnetic-ferromagnetic phase transition in perovskite manganites Nd<SUB>0.5</SUB>Sr<SUB>0.5</SUB>Mn<SUB>1-x</SUB>Co<SUB>x</SUB>O<SUB>3</SUB>( x = 0.03 and 0.05) has been studied in detail by using various techniques, such as the modified Arrott plot and critical isotherm analysis. Basing on the modified Arrott plot method, we obtained the critical parameters of T<SUB>C</SUB> ≈ 234.3 K, β = 0.414 ±0.047 and γ = 1.488 ±0.312 for x = 0.03, and T<SUB>C</SUB> ≈ 221.9 K, β = 0.450 ±0.10 and γ = 1.113 ±0.033 for x = 0.05. The determined values of the critical exponents are in between those expected for the 3-D Heisenberg and mean-field models. With these values, isothermal magnetization data of the samples around T<SUB>C</SUB> fall into two branches of a universal function M(H, ε) = |ε|<SUP>β</SUP> f<SUB>±</SUB> (H/|ε|<SUP>β+ γ</SUP>), where ε = (T-T<SUB>C</SUB>)/T<SUB>C</SUB> is the reduced temperature, f<SUB>+</SUB> for T > T<SUB>C</SUB> and f for . This proves that the critical parameters determined are reliable and in accordance with the scaling hypothesis. Our results also demonstrate an existence of short-range ferromagnetic order in Nd<SUB>0.5</SUB>Sr<SUB>0.5</SUB>Mn<SUB>1-x</SUB>Co<SUB>x</SUB>O<SUB>3</SUB>. Particularly, the Co doping at high concentrations has a tendency leading to long-range ferromagnetic order.</P>