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
Park, J
P.,Jongee
P., Jongee
J.,Park
Park J.
Park, Jongee
Park,J.
J., Park
Park,Jongee
Jongee, Park
Park, J
Job Title
Profesör Doktor
Email Address
jongee.park@atilim.edu.tr
Main Affiliation
Metallurgical and Materials Engineering
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WoS Researcher ID
Sustainable Development Goals
14
LIFE BELOW WATER
0
Research Products
2
ZERO HUNGER
0
Research Products
11
SUSTAINABLE CITIES AND COMMUNITIES
1
Research Products
1
NO POVERTY
0
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION
0
Research Products
7
AFFORDABLE AND CLEAN ENERGY
12
Research Products
5
GENDER EQUALITY
0
Research Products
3
GOOD HEALTH AND WELL-BEING
2
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
0
Research Products
13
CLIMATE ACTION
0
Research Products
6
CLEAN WATER AND SANITATION
0
Research Products
10
REDUCED INEQUALITIES
0
Research Products
4
QUALITY EDUCATION
0
Research Products
15
LIFE ON LAND
0
Research Products
16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
17
PARTNERSHIPS FOR THE GOALS
0
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
0
Research Products
Documents
53
Citations
927
h-index
19
Documents
50
Citations
890
Scholarly Output
57
Articles
45
Views / Downloads
21/0
Supervised MSc Theses
3
Supervised PhD Theses
0
WoS Citation Count
819
Scopus Citation Count
855
WoS h-index
19
Scopus h-index
19
Patents
0
Projects
1
WoS Citations per Publication
14.37
Scopus Citations per Publication
15.00
Open Access Source
7
Supervised Theses
3
Google Analytics Visitor Traffic
| Journal | Count |
|---|---|
| Ceramics International | 10 |
| Journal of Nanoscience and Nanotechnology | 3 |
| Applied Surface Science | 2 |
| 3rd International Conference on NANOCON -- SEP 21-23, 2011 -- Brno, CZECH REPUBLIC | 2 |
| Advanced Materials Research -- 2012 International Conference on Advances in Materials Science and Engineering, AMSE 2012 -- 9 December 2012 through 10 December 2012 -- Seoul -- 95488 | 2 |
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Now showing 1 - 10 of 45
Article Citation - WoS: 11Citation - Scopus: 10Synthesis and Characterization of Hydrothermally Grown Potassium Titanate Nanowires(Korean Assoc Crystal Growth, inc, 2015) Kapusuz, Derya; Kalay, Y. Eren; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringPotassium titanate (KT) nanowires were synthesized by a one-step hydrothermal reaction between TiO2 and aqueous KOH solution. The effects of KOH concentration and reaction time on hydrothermal formation and KT nanowire growth were investigated. The nanowire growth mechanism was elucidated using a combined study of powder X-ray diffraction, and scanning and transmission electron microscopy. The results revealed that hydrothermal growth was initiated by the formation of amorphous-like Ti-O-K sheets in anatase. Increasing hydrothermal reaction time caused the transformation of anatase to Ti-O-K sheets, from which potassium hexa-titanate (K2Ti6O13) nuclei formed and grew to establish one-dimensional morphology through preferential growth along the b-axis. It was revealed that the hydrothermal reactions followed a quite different mechanism than the well-known calcination route. Potassium tetra-titanate (K2Ti4O9) crystals formed in the amorphous region using the hexa-titanate phase as a nucleation site for heterogeneous crystallization. Increasing the KOH concentration in the solution accelerated the hydrothermal reaction rate.Article Citation - WoS: 10Alkaline Hydrothermal Synthesis, Characterization, and Photocatalytic Activity of Tio2 Nanostructures: the Effect of Initial Tio2 Phase(Amer Scientific Publishers, 2019) Erdogan, Nursev; Park, Jongee; Choi, Woohyuk; Kim, Soo Young; Ozturk, AbdullahOne-dimensional (1D) titanate nanostructures were synthesized by hydrothermal route, using commercially available TiO2 (P25) and anatase powders as precursor materials and strong NaOH solution as catalyzer. The prepared titanates were calcined, followed by protonation to produce TiO2 nanostructures having enhanced photocatalytic and photovoltaic properties. The synthesized TiO2 1D nanostructures were characterized using field-emission scanning electron microscope, high-resolution electron microscope, X-ray diffraction analysis, and UV-Vis photospectroscopy to understand the effect of initial TiO2 phase on morphological and crystallographic features, and bandgap. Methylene blue degradation test was applied to evaluate the photoactivity of the products obtained after different stages of the process. The findings indicate that 1D TiO2 nanostructures form by different mechanisms from dissolved aggregates during hydrothermal process, depending on the crystal structure of the initial precursor used. Photocatalytic test results reveal that protonated titanates have considerable adsorption capability, while photocatalytic degradation depends on TiO2 transformation.Article Citation - WoS: 25Citation - Scopus: 26Identifying the Potentials for Charge Transport Layers Free N-P Homojunction-Based Perovskite Solar Cells(Pergamon-elsevier Science Ltd, 2022) Khan, Danish; Sajid, Sajid; Khan, Suliman; Park, Jongee; Ullah, IhsanPerovskite solar cells (PSCs) with no charge transport layers (CTLs) could be one of the major device architectures for the production of simple and low-cost devices. However, CTLs-free PSCs based on n-p homojunction have yet to show high power conversion efficiency (PCE), which is most likely due to inadequate light-and charge-management in the p-type perovskite. The device operation is examined using Solar Cell Capacitance Simulator (SCAPS)-software, and a novel n-p homojunction design is proposed to attempt efficient CTLs-free PSCs. Several aspects of p-type layer that can affect device performance, such as acceptor density, photon harvesting capability, defects density, and resistances to the transport of charge-carriers are scrutinized and adjusted. Furthermore, the effects of different work-functions of metal electrodes are examined. A suitable acceptor concentration is required for oriented charge transport. It is determined that a p-type perovskite with a thickness of 0.3 mu m is advantageous for high performance. A metal electrode with a high work-function is essential for efficient device. Consequently, a PCE of 15.60% is obtained with an optimal defect density of E15 cm(-3), indicating that n-p homojunction-based CTLs-free PSCs are promising since they simplify the device design and fabrication process while retaining an acceptable PCE.Article Citation - WoS: 31Citation - Scopus: 37Effect of Initial Water Content and Calcination Temperature on Photocatalytic Properties of Tio2 Nanopowders Synthesized by the Sol-Gel Process(Elsevier Sci Ltd, 2015) Agartan, Lutfi; Kapusuz, Derya; Park, Jongee; Ozturk, AbdullahThe effects of initial water content and calcination temperature on sol gel synthesized TiO2 powders were studied. Mother solutions had water/Ti-precursor mole ratios (R ratio) of 1, 5, 10, and 50. Dried aerogels were calcined for 3 h at temperatures of 300, 400, and 500 degrees C to obtain crystallized TiO2 nanopowders in the range of 15-30 nm. PE-scanning electron microscopy and X-ray diffraction techniques were employed to investigate the morphological and structural properties of the nanopowders synthesized. Profound effect of gel viscosity was observed on the formation mechanism and extent of crystallinity in the powders. Methylene blue degradation test results suggest, photocatalytic performance is enhanced as initial water content and calcination temperature increased. Band-gap energy of the powders ranged from 3.09 to 3.27 eV. Overall, this study shows that initial water content and calcination regime have a profound effect on the phase assembly, crystallite size, band-gap energy, and photocatalytic performance of sol gel synthesized TiO2 nanopowders. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Article Citation - WoS: 23Citation - Scopus: 27Facile synthesis of CsPbBr3/PbSe composite clusters(Taylor & Francis Ltd, 2018) Thang Phan Nguyen; Ozturk, Abdullah; Park, Jongee; Sohn, Woonbae; Tae Hyung Lee; Jang, Ho Won; Kim, Soo YoungIn this work, CsPbBr3 and PbSe nanocomposites were synthesized to protect perovskite material from self-enlargement during reaction. UV absorption and photoluminescence (PL) spectra indicate that the addition of Se into CsPbBr3 quantum dots modified the electronic structure of CsPbBr3, increasing the band gap from 2.38 to 2.48 eV as the Cs:Se ratio increased to 1:3. Thus, the emission color of CsPbBr3 perovskite quantum dots was modified from green to blue by increasing the Se ratio in composites. According to X-ray diffraction patterns, the structure of CsPbBr3 quantum dots changed from cubic to orthorhombic due to the introduction of PbSe at the surface. Transmission electron microscopy and X-ray photoemission spectroscopy confirmed that the atomic distribution in CsPbBr3/PbSe composite clusters is uniform and the composite materials were well formed. The PL intensity of a CsPbBr3/PbSe sample with a 1:1 Cs: Se ratio maintained 50% of its initial intensity after keeping the sample for 81 h in air, while the PL intensity of CsPbBr3 reduced to 20% of its initial intensity. Therefore, it is considered that low amounts of Se could improve the stability of CsPbBr3 quantum dots.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, AbdullahEffect 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 A Benchmark of Expert-Level Academic Questions to Assess AI Capabilities(Nature Portfolio, 2026) Phan, Long; Gatti, Alice; Li, Nathaniel; Khoja, Adam; Kim, Ryan; Ren, Richard; Scaramuzza, Davide; Park, JongeeBenchmarks are important tools for tracking the rapid advancements in large language model (LLM) capabilities. However, benchmarks are not keeping pace in difficulty: LLMs now achieve more than 90% accuracy on popular benchmarks such as Measuring Massive Multitask Language Understanding(1), limiting informed measurement of state-of-the-art LLM capabilities. Here, in response, we introduce Humanity's Last Exam (HLE), a multi-modal benchmark at the frontier of human knowledge, designed to be an expert-level closed-ended academic benchmark with broad subject coverage. HLE consists of 2,500 questions across dozens of subjects, including mathematics, humanities and the natural sciences. HLE is developed globally by subject-matter experts and consists of multiple-choice and short-answer questions suitable for automated grading. Each question has a known solution that is unambiguous and easily verifiable but cannot be quickly answered by internet retrieval. State-of-the-art LLMs demonstrate low accuracy and calibration on HLE, highlighting a marked gap between current LLM capabilities and the expert human frontier on closed-ended academic questions. To inform research and policymaking upon a clear understanding of model capabilities, we publicly release HLE at https://lastexam.ai.Article Citation - WoS: 44Citation - Scopus: 43Sol-Gel Synthesis and Photocatalytic Activity of B and Zr Co-Doped Tio2(Pergamon-elsevier Science Ltd, 2013) Kapusuz, Derya; Park, Jongee; Ozturk, AbdullahEffects 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.Article Citation - WoS: 29Citation - Scopus: 29A Newly Constructed Photoactive System, Fe(iii)-c/N-bi2< for Efficient Visible Light Photocatalysis(Elsevier Science Sa, 2018) Sudrajat, Hanggara; Park, Jongee; Hartuti, Sri; Park, Jongee; Park, Jongee; Metallurgical and Materials Engineering; Metallurgical and Materials EngineeringIn this study, two strategies are simultaneously applied for photocatalytic activity enhancement of Bi2O3. The first strategy is to increase the light absorption via simultaneous carbon and nitrogen doping. The second strategy is to increase the charge carrier separation via Fe grafting. Transmission electron microscopy observation reveals the presence of Fe nanoclusters resided on the Bi2O3 surface. Near edge Xray absorption fine structure (NEXAFS) analysis confirms the valence state of the Fe species to be +3, and their coordination to be octahedral. The C K-edge and N K-edge NEXAFS spectra furthermore confirm the incorporation of C and N species in the Bi2O3 structure. This newly constructed photocatalyst, denoted as Fe(III)-C/N-Bi2O3, shows appreciably enhanced photocatalytic performance for the decomposition of 2,4-dichlorophenol under visible light as compared to bare Bi2O3. (C) 2018 Elsevier B.V. All rights reserved.Article Citation - WoS: 32Citation - Scopus: 28Photocatalytic activity of hydroxyapatite-precipitated potassium titanate whiskers(Elsevier Science Sa, 2010) Park, JongeePhotocatalytic properties of hydroxyapatite (HAP)-precipitated multifunctional potassium titanate (KT) whiskers were investigated in terms of the decomposition of methylene blue (MB) in aqueous solution under UV irradiation. Hydroxyapatite was formed on the surface of KT whiskers through a biomimetic process in simulated body fluid (SBF). The SBF used in this investigation had concentrations of calcium and phosphate ions 10 times greater than those of human plasma. Results revealed that hydroxyapatite precipitation enhanced the photocatalytic activity of the KT whiskers. In the case of unreacted KT whisker, complete degradation of methylene blue took 5.5 h, on the other hand degradation time decreased to 3.5 h when the whisker was precipitated with hydroxyapatite. (C) 2009 Elsevier B.V. All rights reserved.
