Park, Jongee
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Jongee Park
P.,Jongee
P., Jongee
J.,Park
Park J.
Park, Jongee
Park,J.
J., Park
Park,Jongee
Jongee, Park
P.,Jongee
P., Jongee
J.,Park
Park J.
Park, Jongee
Park,J.
J., Park
Park,Jongee
Jongee, Park
Job Title
Profesör Doktor
Email Address
jongee.park@atilim.edu.tr
Main Affiliation
Metallurgical and Materials Engineering
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Website
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Scholarly Output
54
Articles
40
Citation Count
578
Supervised Theses
3
51 results
Scholarly Output Search Results
Now showing 1 - 10 of 51
Article Citation - WoS: 4Citation - Scopus: 4Diethanolamine Modified Perovskite-Substrate Interface for Realizing Efficient Esl-Free Pscs(Mdpi, 2023) Sajid, Sajid; Alzahmi, Salem; Wei, Dong; Ben Salem, Imen; Park, Jongee; Obaidat, Ihab M.; Metallurgical and Materials EngineeringSimplifying device layout, particularly avoiding the complex fabrication steps and multiple high-temperature treatment requirements for electron-selective layers (ESLs) have made ESL-free perovskite solar cells (PSCs) attractive. However, the poor perovskite/substrate interface and inadequate quality of solution-processed perovskite thin films induce inefficient interfacial-charge extraction, limiting the power conversion efficiency (PCEs) of ESL-free PSCs. A highly compact and homogenous perovskite thin film with large grains was formed here by inserting an interfacial monolayer of diethanolamine (DEA) molecules between the perovskite and ITO substrate. In addition, the DEA created a favorable dipole layer at the interface of perovskite and ITO substrate by molecular adsorption, which suppressed charge recombination. Comparatively, PSCs based on DEA-treated ITO substrates delivered PCEs of up to 20.77%, one of the highest among ESL-free PSCs. Additionally, this technique successfully elongates the lifespan of ESL-free PSCs as 80% of the initial PCE was maintained after 550 h under AM 1.5 G irradiation at ambient temperature.Article Citation - WoS: 17Citation - Scopus: 18Antisolvent-Fumigated Grain Growth of Active Layer for Efficient Perovskite Solar Cells(Pergamon-elsevier Science Ltd, 2021) Sajid, Sajid; Khan, Suliman; Khan, Ayub; Khan, Danish; Issakhov, Alibek; Park, Jongee; Metallurgical and Materials EngineeringHigh efficiency of perovskite solar cell can be obtained through various approaches, including materials and interface engineering, device modification and fabrication techniques. In all approaches, the quality of the perovskite layer has a significant impact on the efficiency of the perovskite solar cell. Antisolvent dripping is widely used in almost all fabrication methodologies to achieve a high-quality perovskite layer. However, in the conventional antisolvent dripping, there are several factors (antisolvent volume, time and point of dripping, etc.) to be strictly followed. Due to these difficult and critical tricks, researchers often get perovskite layers with pinholes, small grains, and wide grain boundaries that deteriorate the performance of the perovskite solar cells. In order to produce perovskite films with large-scale grains, narrow boundaries and smooth surface morphology, a sealed antisolvent-fumigated process is implemented. There is no need to make any substantial efforts to achieve optimal conditions for the fabrication of high-quality perovskite layers using the antisolvent-fumigated strategy. Consequently, the efficiency of perovskite solar cell improves dramatically from 18.65% to 21.45%. Our findings present a new and convenient method for fabricating highly efficient perovskite solar cells.Article Citation - WoS: 4Citation - Scopus: 6A Study on Microstructural Characterization of the Interface Between Apatite-Wollastonite Based Glass Ceramic and Feldspathic Dental Porcelain(Elsevier Sci Ltd, 2016) Pekkan, Gurel; Pekkan, Keriman; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringIn this study, the contact area between the glass ceramic containing apatite [Ca-10(PO4)6(O,F-2)] and wollastonite [CaO center dot SiO2] crystals (A-W glass ceramic) and feldspathic dental porcelain was characterized using scanning electron microscope and energy dispersive spectroscopy. Alumina-added A W glass ceramics were prepared by sintering glass compacts in the MgO-CaO-SiO2-P2O5-Al2O3 system at 1100 degrees C. Commercially available dental porcelains for alumina frameworks were applied on the A-W glass ceramic specimen by brushing and carving, and then fired at 960 degrees C using an electrically heated vacuum-furnace. Results revealed that veneering of feldspathic dental porcelain on alumina-added A-W glass ceramic is possible by an interaction between them, with which a diffusion process involving i) seperation of the phases forming the alumina-added A-W glass ceramic, ii) chemical diffusion of elements between alumina-added A-W glass ceramic and feldspathic dental porcelain, and iii) formation of an interface layer, is taking place. The system studied has interfacial characteristics similar to the commercially available dental materials currently used in restorative dentistry. Hence, it may be further processed for potential clinical applications.Article Citation - WoS: 3Citation - Scopus: 4Friction and Wear Behavior of Selected Dental Ceramics(World Scientific Publ Co Pte Ltd, 2009) Park, Jongee; Pekkan, Gurel; Ozturk, Abdullah; Metallurgical and Materials EngineeringThe purpose of this study was to determine the friction coefficients and wear rates of six commercially available dental ceramics including IPS Empress 2 (E2), Cergo Pressable Ceramic (CPC), Cercon Ceram (CCS) and Super porcelain EX-3 (SPE). Bovine enamel (BE) was also tested as a reference material for comparison purposes. Samples of the dental ceramics were prepared according to the instructions described by the manufacturers in disk-shape with nominal dimensions of 12 mm x 2 mm. The wear tests were performed by means of a pin-on-disk type tribometer. The friction coefficients and specific wear rates of the materials were determined at a load of 10 N and rotating speed of 0.25 cm/s without lubrication. Surface morphology of the wear tracks was examined using a scanning electron microscope. Statistical analyses were made using one-way ANOVA and Turkey's HSD (P < 0.05).Article Tio2 Films With Various Crystal Structures for Single and Bilayer Photoanodes of Dye-Sensitized Solar Cells(2018) Erdoğan, Nursev; Park, Jongee; Öztürk, Abdullah; Metallurgical and Materials EngineeringPhase pure and composite TiO2 nanopowders exhibiting various crystal structures (anatase, rutile and brookite) are used asphotoanode in dye-sensitized solar cells. The nanopowders are deposited in paste form onto a conducting oxide glass usingdoctor blade method in single layer and bilayers. The highest solar efficiency achieved by the single layer photoanode composedof > 99 wt % anatase crystals was 2.86 %. The solar efficiency of 4.93 % has been harvested via bilayer photoanode built byapplying a layer consisting 55 wt % anatase and 45 wt % rutile phase nanoparticles on top of the layer composed of a mixtureof > 99 wt % anatase crystals. The improved photovoltaic performance is attributed to anatase dominated bottom layer whichfacilitates electron charge generation with high surface area and charge transport by proper crystal structure as well assynergistic effect of binary phase content of the photoanodes. The porous structure of top layer enhances diffusion of theI−/I3−electrolyte in the bilayer TiO2 photoanode.Article Citation - WoS: 14Citation - Scopus: 14Effects of Fluorination and Thermal Shock on the Photocatalytic Activity of Bi2o3< Nanopowders(Elsevier, 2021) Bouziani, Asmae; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringFluorinated Bi2O3 (F-Bi2O3) nanopowder was prepared via fluorination followed by thermal shock of alpha-Bi2O3 nanopowder. The XRD, FTIR, SEM, and DRS characterization techniques were employed to investigate the effects of fluorine (F) insertion into the alpha-Bi2O3 host and the thermal shock from different temperatures. The crystal structure, optical and photocatalytic properties of the F-Bi2O3 nanopowders prepared were researched. The XRD results confirmed the substitution of O2- with F-. The FTIR results revealed that the coordination of Bi atoms changed upon F- substitution. The incorporation of F into the alpha-Bi2O3 host and thermal shock did not influence the morphology but modified the band structure of alpha-Bi2O3, leading to a red-shift in the optical absorption edge. Also, the bandgap narrowed from 2.8 eV to 2.6 eV. The density functional theory calculation proved that the F 2p orbitals were positioned in the valence band (VB), resulting in broader and more spread bands for F-Bi2O3. The results suggested that the photoexcited charge carrier mobility in the valence band (VB) and conduction band (CB) are enhanced upon F insertion into alpha-Bi2O3. The photocatalytic efficiency of the synthesized nanopowders was assessed by the degradation of Bromocresol Green (BG) under visible light illumination. Photocatalytic activity improved upon fluorination. The F-Bi2O3 nanopowders thermally shocked from higher temperatures showed negligible photocatalytic performance. The best photocatalytic performance of 70% BG degradation was realized after 180 min visible irradiation for the F-Bi2O3 nanopowder thermal shocked from 500 degrees C.Article Citation - WoS: 42Citation - Scopus: 41Silver-Loaded Tio2 Powders Prepared Through Mechanical Ball Milling(Elsevier Sci Ltd, 2013) Aysin, Basak; Ozturk, Abdullah; Park, Jongee; Metallurgical and Materials EngineeringSilver (Ag) was loaded on TiO2 powders through mechanical ball milling. Ag-loading was accomplished by adding 4.6, 9.2, and 13.8 ml of AgNO3 solution to the TiO2 powders during the milling process. The resulting powder was characterized by XRD, XPS, SEM, and EDS. The photocatalytic activity of the silver-loaded powder was evaluated in terms of the degradation of methyl orange (MO) solution under ultraviolet (UV) illumination. XRD patterns were refined using the Rietveld analysis to determine the lattice parameters. XRD analysis suggested that Ag was loaded on TiO2 powders in the form of AgO. X-ray photoelectron spectroscopy and Rietveld analysis revealed that silver did not dope into the crystal structure of TiO2. SEM investigations confirmed that ball milling caused a decrease in the average particle size of the powders. Silver-loading improved the photocatalytic activity of the TiO2 powders. The TiO2 powder ball milled without Ag-loading degraded 46% of the MO solution whereas the ball milled with 13.8 ml AgNO3 solution degraded 96% of the MO solution under 1 h UV irradiation. Moreover, TiO2 powders gained antibacterial property after Ag-loading. (c) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Article Citation - WoS: 15Citation - Scopus: 17Inorganic Hole Transport Materials in Perovskite Solar Cells Are Catching Up(Elsevier Sci Ltd, 2023) Sajid, Sajid; Alzahmi, Salem; Ben Salem, Imen; Park, Jongee; Obaidat, Ihab M.; Metallurgical and Materials EngineeringMore research is required to further optimize device efficiency, stability, and reduce the materials cost as perovskite solar cells (PSCs) approach to industrialization. Modulating the optoelectronic features and chemical coupling of the hole transport materials (HTMs) remains a prominent field of study in PSCs due to the significant impact these materials have on the device performance and stability. In order to speed up the commercialization of these cells, it is also important to use cost-effective HTMs in PSCs. InorganicHTMs are superior to other types of HTMs in terms of their advantages in boosting device performance and producing PSCs at a reasonable cost, in addition to their superior charge transport capabilities, desired energy levels, and intrinsic thermal and chemical stability. A detailed overview of inorganicHTMs, including metal oxides, cyanates, phthalocyanines, chalcogenides, nitrides, and carbides, is presented in this review. After briefly discussing the primary physical and optoelectronic characteristics of inorganic-HTMs, the critical functions of the above-mentioned materials as HTMs in PSCs are addressed. This review concludes by offering suggestions for future research that could considerably boost the performance of the PSCs with cost-effective inorganic-HTMs.Article Citation - WoS: 8Effect of H2o Ratio on Photocatalytic Activity of Sol-Gel Tio2 Powder(Ice Publishing, 2013) Agartan, Lutfi; Kapusuz, Derya; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringEffect of water/tetraethyl orthotitanate molar ratio (R) on the formation and morphology of sol-gel-derived titania powder has been studied. Solutions for R of 3 and 5 have been prepared. Initial viscosity of the solutions and viscosity of the gels prepared by aging the solutions for some time were measured. Results revealed that lower gel viscosities lead to better crystallization of the aerogel. Aerogels were dried at 80 degrees C for 24 h and then calcined at 300 degrees C for 1 h to obtain titania powders. The structural and morphological analyses of the powders were performed using X-ray diffraction and scanning electron microscopic characterization techniques. Titania particles obtained after calcination composed of only anatase phase and were in the size range of 9-50 nm. The photocatalytic activity of the powders was evaluated in terms of the degradation of methylene blue (MB) solution under UV (ultraviolet) illumination. A diffuse reflectance spectroscopy was used for the band gap energy measurements. Results revealed that R had a profound effect on the particle morphology and photocatalytic activity of sol-gel-derived titania powders. The titania powders prepared from the solution for R of 5 degraded 99.47% of MB solution under UV illumination in 90 min.Article Citation - WoS: 42Citation - Scopus: 41Sol-Gel Synthesis and Photocatalytic Activity of B and Zr Co-Doped Tio2(Pergamon-elsevier Science Ltd, 2013) Kapusuz, Derya; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringEffects of boron (B) and/or zirconium (Zr) doping on photocatalytic activity of sol-gel derived titania (TiO2) powders were investigated. A conventional, non-hydrous sol-gel technique was applied to synthesize the B, Zr doped/co-doped TiO2 powders. Doping was made at molar ratios of Ti/B=1 and Ti/Zr=10. Sol-gel derived xero-gels were calcined at 500 degrees C for 3 h. The crystal chemistry and the morphology of the undoped and B, Zr doped/co-doped TiO2 nanoparticles were investigated using X-ray diffractometer and scanning electron microscope. Nano-scale (9-46 nm) TiO2 crystallites were obtained after calcination. Doping and co-doping decreased the crystallite size. Photocatalytic activity was measured through the degradation of methylene blue (MB) under 1 h UV-irradiation using a UV-vis spectrophotometer. Results revealed that B doping into anatase caused the formation of oxygen vacancies, whereas Zr addition caused Ti substitution. Both B and Zr ions had a profound effect on the particle morphology and photocatalytic activity of TiO2. The photocatalytic activity of B and Zr doped TiO2 particles increased from 27% to 77% and 57%, respectively. The best activity (88.5%) was achieved by co-doping. (C) 2013 Elsevier Ltd. All rights reserved.
