Seong-Ho Baek

Seong-Ho Baek
Daegu Gyeongbuk Institute of Science and Technology | DGIST · Green Energy Research Division

Ph. D.

About

63
Publications
5,152
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1,282
Citations
Additional affiliations
June 2005 - present
Daegu Gyeongbuk Institute of Science and Technology
Position
  • Senior Researcher

Publications

Publications (63)
Article
Double perovskites oxides (DPOs)-based bi-functional catalysts (oxygen reduction reaction, ORR, and oxygen evolution reaction, OER) have gained great importance due to their low oxygen electrode overpotential (η) performance. We demonstrate a nickel-based DPO material, La2FeNiO6 (LFNO), prepared via the sol-gel polymer method and a controlled synth...
Article
Recently, hybrid supercapacitors (HSCs) garner significant attention as alternative energy storage devices that bridge the gap between lithium–ion batteries (LIBs) and electric double–layer capacitors (EDLCs). In this work, we investigate the effects of solvothermal growth with controlled mixture ratio of ethanol and water solution on morphological...
Article
Triboelectric Nanogenerators A triboelectric nanogenerator is an environmentally friendly energy harvesting technology that has attracted considerable research attention as a sustainable energy source. In article number 2000829 by Geon‐Ju Choi, Seong‐Ho Baek, and Il‐Kyu Park, a synergetic enhancement of triboelectric nanogenerators’ performance usi...
Article
A triboelectric nanogenerator (TENG) is an environmentally friendly energy harvesting technology that has attracted considerable research attention as a sustainable energy source. This paper reports a synergetic enhancement of TENG performance by using patterned polyvinylidene fluoride (PVDF) and nylon membranes polymer membranes based on a facile...
Article
In this study, we investigated the effects of SnO artificial layer on the solid electrolyte interphase (SEI) in SiO anodes by varying the layer thickness via the atomic layer deposition technique. Two major SEI components, namely LiF and Li2CO3, were obtained from the electrolyte decomposition, which appeared on the anode surface depending on the a...
Article
Pseudocapacitors can exhibit higher capacity compared to traditional electrostatic or electric double–layer capacitors while they can provide faster power delivery and longer cycling ability than lithium–ion batteries. In this study, we demonstrate the hierarchical structures of NiCo hydroxides, which are grown on Ni foam via facile hydrothermal me...
Article
The bifunctional electrocatalyst plays a pivotal role in renewable‐energy technologies metal‐air‐batteries and water electrolysis. The advantage of the alkaline environment allows such technologies to utilize several low‐cost and efficient non‐noble transition metal oxides. Particularly, perovskite oxides (POs) of high intrinsic catalytic activity...
Article
Wearable mechanical energy harvesting technologies have been achieved much attention for the wireless sustainable power source applications. In this study, we have fabricated polyvinylidene fluoride (PVDF)/graphene quantum dot (GQD) composite nanofibers (NFs), which showed improved triboelectric nanogenerator (TENG) performance. PVDF/GQD composite...
Article
Recently, the combination of nickel (Ni) and cobalt (Co) binary hydroxides have been regarded as a promising class of materials due to their excellent redox reversibility and relatively high capacity. In this work, we demonstrate Ni and Co layered double hydroxides (NiCo–LDHs) on Ni–coated textile for wearable supercapacitor (SC) applications. Ni–c...
Article
High quality Al-doped ZnO (AZO) films are advantageous for many applications. Their properties can be tuned by controlling the doping concentration and intrinsic defect density. In this work, high-quality AZO films have been synthesized using the atomic layer deposition (ALD) technique. Throughout the doping cycle and post-annealing treatments unde...
Article
Full-text available
In this work, we conduct a comparative study of boron-doped SiO (HB-SiO) and carbon-coated SiO (HC-SiO) to find an effective means of improving the electrochemical performances of SiO anode materials during long-cycle tests. Carbon-coating processes are widely introduced to provide electrical pathways for charge transfer, resulting in a decrease of...
Article
Several attempts have been made to investigate the PV cell parameters’ dependence on temperature under normal illumination conditions, although there is no report available in the literature providing information about this dependence in the case of high illumination conditions. We therefore investigate analytically the dependence on temperature of...
Article
Generally, a selective SiNW-type structure is used to avoid resistive loss in SiNW-based solar cells. However, the performance of these selective SiNW-based solar cells is lower than that of conventional Si solar cells, due to their low collection efficiency and high series resistance. Herein, a novel process is developed to enhance the collection...
Article
One- to three-dimensional alignments of semiconductors on the micro- or nanoscale have been achieved to tailor their opto-physicochemical properties and improve their photoelectrochemical (PEC) performance. Here, to the best of our knowledge, we report for the first time the fabrication of vertically aligned, well-ordered WO3 microdisc arrays via a...
Article
Conducting Ag and Al co-doped ZnO (ZnO:Al:Ag) nanostructures were synthesized using sol-gel process. The effects of Ag incorporation on the structural, optical, electrical, and photoluminescent properties of ZnO:Al:Ag nanostructures were studied. The crystalline quality of the nanostructures was found to be improved by Ag doping concentration of 0....
Article
Simultaneous reduction and doping of the graphene oxide (GO) is an important issue for low temperature processed flexible electronic devices. A low temperature method for reduction and ambipolar doping has been developed which yield the doped reduced GO with wide range of work function with a mass production using tetra-methyl ammonium hydroxide (T...
Article
We demonstrate the enhancement of output power from a ZnO nanorod (NR)-based piezoelectric nanogenerator by using Si microhole (Si-μH) arrays. The depth-controlled Si-μH arrays were fabricated by using the deep reactive ion etching method. The ZnO NRs were grown along the Si-μH surface, in holes deeper than 20 μm. The polymer layer, polydimethylsil...
Article
Electronic recombination loss is an important issue for photovoltaic (PV) devices. While it can be reduced by using a passivating layer, most of the techniques used to prepare passivating layers are either not cost effective or not applicable for device applications. Previously, it was reported that a low cost sol-gel derived Al-rich zinc oxide (Zn...
Article
We introduce a one-step process that consists of thermal disproportionation and impurity doping to enhance the reversible capacity and electrical conductivity of silicon monoxide (SiO)-based negative electrode materials in Li-ion batteries. Transmission electron microscope (TEM) results reveal that thermally treated SiO at 900 °C (H-SiO) consists o...
Article
Herein, we suggest a facile and cost-effective metal-assisted chemical etching (MACE) method to synthesize uniformly Ag-coated silicon nanowires (SiNWs) using redox reaction, which provides structural and electrical effects on Si negative electrodes at the same time. The combinations of SiNW geometry and Ag nanoparticle (AgNP) coatings are benefici...
Article
Fe2O3 nanorod/carbon nanofiber (CNF) composites were prepared by the electrochemical deposition of Fe2O3 on a web of CNFs, which was then used as a free-standing anode. The conductive, three-dimensional structure of the CNF web allowed for the electrodeposition of the Fe2O3 nanorods, while its high conductivity made it possible to use the composite...
Article
The rate capability of a Li4Ti5O12 (LTO)-based anode in a lithium ion battery can be easily improved by electron beam (EB) irradiation without the need for complicated synthetic procedures. The electrode prepared with EB-irradiated LTO at a 50 kGy dose has an enhanced rate capability while retaining a discharge capacity of 100 mAh g−1, even at the...
Article
Full-text available
In this paper, we present an optical model that simulates the light trapping and scattering effects of a paraboloid texture surface first time. This model was experimentally verified by measuring the reflectance values of the periodically textured silicon (Si) surface with the shape of a paraboloid under different conditions. A paraboloid texture s...
Article
Full-text available
We report the morphological evolution of ZnAl-based hybrid nanostructures from ZnAl layered double hydroxide (LDH) to ZnO nanorods (NRs) grown by a hydrothermal method depending on the thickness of the Al2O3/ZnO double seed layer. The thickness of the Al2O3/ZnO double seed layer was controlled by an atomic layer deposition system. We found that the...
Article
Full-text available
Al rich zinc oxide nano-structured films were synthesized using spin coating sol-gel technique. The films were annealed in oxygen ambient in the temperature range of 200-700 °C. The structural, optical, and photoluminescence (PL) properties of the films were studied at various annealing temperatures using X-ray diffraction spectroscopy, field emiss...
Article
We report on the enhancement of the output voltage from ZnO nanorod (NR)-based piezoelectric nanogenerators (PNGs) fabricated by using a double-sided stainless steel (SUS) substrate. The ZnO NRs were successfully grown on both sides of the SUS substrate by using a hydrothermal method. The ZnO NRs showed different crystalline quality on the front an...
Article
Enhanced output power from a ZnO nanorod (NR)-based piezoelectric nanogenerator (PNG) is demonstrated by forming a heterojunction with Si micropillar (MP) array. The length of the SiMP array, which was fabricated by electrochemical etching, was increased systematically from 5 to 20 μm by controlling the etching time. Our structural and optical inve...
Article
Full-text available
Electronic recombination losses can be reduced via passivation of silicon surfaces. Most techniques available in the literature are either not cost effective or not applicable for solar cell applications. We investigate low cost sol–gel derived Al-rich zinc oxide (ZnO:Al) film and its effective passivation of p-type silicon surfaces. Herein, we pre...
Article
Al-doped ZnO (AZO)/Ag grid hybrid transparent conductive electrode (TCE) structures were fabricated at a low temperature by using electrohydrodynamic jet printing for the Ag grids and atomic layer deposition for the AZO layers. The structural investigations showed that the AZO/Ag grid hybrid structures consisted of Ag grid lines formed by Ag partic...
Article
A systematic study of hydrogen sintered aluminum rich zinc oxide (AZO) films is made from the view point of their application as surface passivation layer for silicon solar cell. AZO films of various Al and Zn molar concentration ratios (0 < R-Al/Zn < 40%) are made and their electrical and optical properties are studied. The lowest surface recombin...
Article
We report on the growth of ZnO nanorods (NRs) grown on graphite and silicon substrates via an all-solution process and also studied the characteristics of their heterojunctions. Structural investigations indicated that morphological and crystalline properties were not significantly different for the ZnO NRs on both substrates. However, optical prop...
Article
The dependency on Pin of PV cell parameters of Si solar cells with various structures has been investigated. The analytically-predicted values of Rsh and Rs decreased with increases of Pin. The decrease of Rsh may be due to light induced degradation of the PV cells. The reduction in Rs values may be due to an increase of conductivity of the active...
Article
Full-text available
We demonstrate the fabrication of a graphene/ZnO nanorod (NR) hybrid structure by mechanical exfoliation of ZnO NRs grown on a graphite substrate. We confirmed the existence of graphene sheets on the hybrid structure by analyzing the Raman spectra and current-voltage (I-V) characteristics. The Raman spectra of the exfoliated graphene/ZnO NR hybrid...
Article
We report on the growth of CdO and Cd(OH)2 nanostructures with different morphologies on Si substrates by using a hydrothermal method. Structural and optical investigations showed that the shape and phase could be modified through the growth time and the concentration in the solution. The formation of CdO was dominated during the early stage of gro...
Article
Li4Ti5O12 and Al3+, Zr4+ co-doped Li(4−x/3)Alx Ti(5−5x/3)Zrx O12 (x = 0.01, 0.05, 0.1, 0.15, 0.2) were synthesized at 950 °C via a solid state reaction by using rutile TiO2, Li2 CO3, and Al2O3 as precursors for the anode material of a lithium-ion battery. The average particle sizes of Li(4−x/3)Alx Ti(5−5x/3)Zrx O12 (x = 0, 0.01, 0.05, 0.1, 0.15, 0....
Article
Graphical abstract A study of passivation properties of aluminum rich zinc oxide (AZO) film and its application in PERC solar cells. The diffusion length of PERC (AZO passivating layer with Al local BSF) solar cells enhanced to a value of 571.13 ± 11.42 μm in comparison with of standard (Al BSF on full area) solar cells (218.09 ± 4.36 μm). Improvem...
Article
The effects of Ag doping on the structural, electrical, optical, and photoluminescence properties of sol-gel derived Al rich zinc oxide (Ag-AZO) films are studied. The Al/Zn atomic ratio was constant (similar to 20%) in all the films, whereas the Ag/Zn atomic ratio varied from 0% to 3%. All the films were highly transparent in the 400-1200 nm wavel...
Article
Full-text available
The dependence of performance of silicon nanowires (SiNWs) solar cells on the growth condition of the SiNWs has been described. Metal-assisted electroless etching (MAE) technique has been used to grow SiNWs array. Different concentration of aqueous solution containing AgNO3 and HF for Ag deposition is used. The diameter and density of SiNWs are fou...
Article
We demonstrate the fabrication of solution based low temperature-processed p-type ZnO NRs doped with phosphorous by using a spin-on-dopant method coupled with a hydrothermal process. We confirmed the incorporation of phosphorous dopants into a ZnO crystal by analyzing SIMS profiles, together with the evolution of the photoluminescence spectra. It i...
Article
In this study, we report the effect of the crystallographic orientation of silicon nanowires (SiNWs) on electrochemical performance as a negative electrode material. We synthesize vertically aligned SiNWs from differently oriented Si substrates with axial orientations of Si <100>, <110>, and <111> by the metal-assisted chemical etching method. To i...
Article
An analytical method has been developed to extract all four diode parameters, namely the shunt resistance, series resistance, diode ideality factor, and reverse saturation current density, using a single J-V curve, based on one exponential model of silicon solar cells under high illumination conditions. The slope of the J-V curve (dV/dJ) at a short...
Article
Li4Ti5O12 and Al3+ doped Li(4-x/3)AlxTi(5-2x/3)O12 (x = 0, 0.01, 0.05, 0.1, 0.15, 0.2) are synthesized at 750, 850, 950 degrees C via solid state reaction using TiO2-rutile, Li2CO3 and Al2O3 as precursors. The samples at 850, 950 degrees C have better phase purity than those at 750 degrees C. The preliminary charge-discharge cycling test of undoped...
Article
Eu-doped ZnO nanorods (NRs) emitting several discrete lines in the visible spectrum were synthesized on silicon (100) substrates using a hydrothermal process. Structural investigations by transmission electron microscopy and X-ray diffraction showed that Eu atoms had been incorporated into the ZnO lattice without forming Eu-related alloys. The phot...
Article
Aluminum rich zinc oxide (AZO) film was made on silicon substrates by spin coating using a precursor containing Al and Zn in the 20% atomic ratio. The films were annealed in air atmosphere and in hydrogen ambient. The minimum reflectance (R-lambda) in air annealed (AZO:Air) samples was similar to 2.5% in the vicinity (+/- 50 nm) of 750 nm, however,...
Article
In this study, we fabricated and characterized three dimensional (3D) silicon (Si)/zinc oxide (ZnO) hybrid subwavelength structures to investigate their antireflective properties. Si nanorods (SiNRs) were fabricated by electrochemical etching, and subsequentially we grew ZnO NRs on SiNR as templates by using hydrothermal synthesis. The morphologica...
Article
Full-text available
Al-doped ZnO(AZO) thin films were synthesized using atomid layer deposition(ALD), which acurately controlled the uniform film thickness of the AZO thin films. To investigate the electrical and optical properites of the AZO thin films, AZO films using ALD was controlled to be three different thicknesses (50 nm, 100 nm, and 150 nm). The structural, c...
Article
Surface plasmon (SP)-enhanced light emission mechanism has been investigated for the Ag-coated ZnO/Al2O3 core/shell nanorods (NRs). Structural characterizations showed that the ZnO NRs were covered by conformal Al2O3 layer and coated by Ag nanoparticles (NPs). The optical studies by photoluminescence (PL) showed abnormal variation of PL intensity w...
Article
In this report, we have demonstrated the morphological evolution of the silver nanoparticles (AgNPs) by controlling the growth conditions and its effect on morphology of silicon (Si) during metal-induced electroless etching (MICE). Self-organized AgNPs with peculiarly shape were synthesized by an electroless plating method in a conventional aqueous...
Article
We carried out experimental and simulative investigations of the electrical and optical characteristics of radial p–n junction Si microwire (MW) array solar cells (diameter: 4 μm, height: 12 μm, and period: 12 μm) prepared by electroless etching (EE) methods. Due to its unique geometry, the MW array had an enlarged junction area, enabling efficient...
Article
We report the structural, electrical, and optical characteristics of Al-doped ZnO (ZnO:Al) films deposited on glass by atomic layer deposition (ALD) with various Al2O3 film contents for use as transparent electrodes. Unlike films fabricated by a sputtering method, the diffraction peak position of the films deposited by ALD progressively moved to a...
Article
We introduce a new type of silicon micro-wire (SiMW) solar cell with a conformal zinc oxide (ZnO) nanorods anti-reflection coating (ARC) and discuss the optical and photovoltaic properties of the SiMW solar cells with controlled ZnO nanorods. The fabrication processes were composed of metal-assisted electroless etching combined with photolithograph...
Article
This report proposes newly designed all-solution based processes for fabricating hybrid silicon (Si) wire-planar solar cells having conformal zinc oxide (ZnO) nanorod anti-reflection coating (ARC). The all-solution processes were composed of three steps. First, metal-assisted chemical etching combined with natural lithography was used to fabricate...
Article
Structural, electrical, and optical properties of atomic layer-controlled Al-doped ZnO (ZnO:Al) films grown by atomic layer deposition (ALD) on glass substrates were characterized at various growth temperatures for use as transparent electrodes. The Al atomic content in ZnO:Al films increased due to the reduced ZnO film growth rate with increasing...
Article
Full-text available
In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical etching and, the p-n junction was prepared by spin-on dopant diffusion method. Hydrothermal growt...
Article
Full-text available
Visible light-emitting Ce-doped ZnO nanorods [NRs] without a post thermal annealing process were grown by hydrothermal method on a Si (100) substrate at a low temperature of 90°C. The structural investigations of Ce-doped ZnO NRs showed that the Ce3+ ions were successfully incorporated into the ZnO lattice sites without forming unwanted Ce-related...
Article
We present optimization of electrochemical etching process in p-type silicon because the formation of p-type ordered porous silicon or silicon wire arrays has not been well documented compared with n-type ones. In order to prepare and fabricate p-type silicon wire arrays without pore walls for silicon-based solar cell application, the effect of ele...
Article
The characteristics of optical absorption and photovoltaic properties of silicon(Si) wire solar cells with different aspect ratio have been studied. Vertically aligned Si wire arrays were fabricated by electrochemical etching and p–n junction was prepared by spin-on-dopant (SOD) diffusion method. To demonstrate the effect of wire length, it was con...
Article
The influence of thickness of optimized Al-doped zinc oxide (AZO) front contact layer on an efficiency of a radial p-n junction silicon (Si) solar cell has been studied. Vertically aligned Si wire arrays for the radial p-n junction solar device were fabricated by metal catalytic etching and p-n junction was prepared by spin-on-dopant (SOD) diffusio...
Data
We report on the effects of surface treatment with N 2 , O 2 , and N 2 O plasmas on the work function of indium–tin oxide (ITO). UV photoelectron spectroscopy (UPS) showed that the work function on the ITO surface treated with N 2 O plasma increased more than that on the samples treated with N 2 or O 2 plasma. X-ray photoelectron spectroscopy (XPS)...

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