Sangsul Lee

Prof. Dr. Sangsul Lee

orcid

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2020 in Heliyon
Verified
Journal Article
Open access
JITENDRA Pal SinghJITENDRA Pal Singh
JITENDRA Pal Singh
VSVarsha Singh
Varsha Singh
ASAditya Sharma
Aditya Sharma
GPGanesh Pandey
Ganesh Pandey
Keun Hwa ChaeKeun Hwa Chae
Keun Hwa Chae
SLSangsul Lee
Sangsul Lee
Magnesium oxide remained interesting from long time for several important phenomena like; defect induced magnetism, spin electron reflectivity, broad laser emission etc. Moreover, nanostructures of this material exhibited suitability for different kinds of applications ranging from wastewater treatment to spintronics depending upon their shape and size. In this way, researchers had grown nanostructures in the form of nanoparticles, thin films, nanotubes, nanowalls, nanobelts. Though nanoparticles and thin films are well known form of nanostructures and wide variety of synthesis approaches are available, however, limited methodology for other nanostructures are available. In order to grow these nanostructures in an optimized way an understanding of these methods is essential. Thus, this review article depicts an overview of various approaches for design of different kinds of nanostructures.

3 June 2020 in RSC Advances
Verified
Journal Article
Open access
PDF file
JITENDRA Pal SinghJITENDRA Pal Singh
JITENDRA Pal Singh
JPJae Yeon Park
Jae Yeon Park
VSVarsha Singh
Varsha Singh
SKSo Hee Kim
So Hee Kim
WLWeon Cheol Lim
Weon Cheol Lim
Keun Hwa ChaeKeun Hwa Chae
Keun Hwa Chae
Herein, the size dependent behavior of cobalt ferrite nanoparticles was investigated using synchrotron radiation based techniques. Scanning electron micrographs revealed the enhancement of particle/crystallite size with increase of annealing temperature. Moreover, the shape of these particles also changed with increase of crystallite size. Saturation magnetization increased with increase of crystallite size. The higher saturation magnetization for larger crystallite size nanoparticles was attributed to a cation distribution similar to that of bulk CoFe2O4. The optical band-gap of these nanoparticles decreased from 1.9 eV to 1.7 eV with increase of crystallite size. The enhancement of the optical band-gap for smaller crystallites was due to phenomena of optical confinement occurring in the nanoparticles. Fe L Co L-edge near edge extended X-ray absorption fine structure (NEXAFS) measurements showed that Fe and Co ions remain in the 3+ and 2+ state in these nanoparticles. The results obtained from Fe & Co K-edge X-ray absorption near edge structure (XANES)-imaging experiments further revealed that this oxidation state was possessed by even the crystallites. Extended X-ray absorption fine structure (EXAFS) measurements revealed distribution of Fe and Co ions among tetrahedral (A) and octahedral (B) sites of the spinel structure which corroborates the results obtained from Rietveld refinement of X-ray diffraction patterns (XRD). X-ray magnetic circular di-chroism (XMCD) measurements revealed negative exchange interaction among the ions situated in tetrahedral (A) and octahedral (B) sites. Theoretical and experimental calculated magnetic moments revealed the dominancy of size effects rather than the cation redistribution in the spinel lattice of CoFe2O4 nanoparticles.

10 July 2024 in Energy Advances
Verified
Journal Article
Open access
PDF file
JITENDRA Pal SinghJITENDRA Pal Singh
JITENDRA Pal Singh
HDHarsha Devnani
Harsha Devnani
ASAditya Sharma
Aditya Sharma
WLWeon Cheol Lim
Weon Cheol Lim
ADArchana Dhyani
Archana Dhyani
SLSangsul Lee
Sangsul Lee
Doping, coating, surface modification, formation of composites and control of crystalline orientation can control the capacity retention of Ni-rich cathodes. Furthermore, the design of Co-free Ni-rich cathodes may provide a cost-effective solution.

15 April 2020 in Nanomaterials
Verified
Journal Article
Open access
PDF file
JITENDRA Pal SinghJITENDRA Pal Singh
JITENDRA Pal Singh
JPJae Yeon Park
Jae Yeon Park
Keun Hwa ChaeKeun Hwa Chae
Keun Hwa Chae
DADocheon Ahn
Docheon Ahn
SLSangsul Lee
Sangsul Lee
Herein, we report the soft X-ray absorption spectroscopic investigation for Li(Ni0.8Co0.1Mn0.1)O2 cathode material during charging and discharging. These measurements were carried out at the Mn L-, Co L-, and Ni L-edges during various stages of charging and discharging. Both the Mn and Co L-edge spectroscopic measurements reflect the invariance in the oxidation states of Mn and Co ions. The Ni L-edge measurements show the modification of the oxidation state of Ni ions during the charging and discharging process. These studies show that eg states are affected dominantly in the case of Ni ions during the charging and discharging process. The O K-edge measurements reflect modulation of metal–oxygen hybridization as envisaged from the area-ratio variation of spectral features corresponding to t2g and eg states.

25 March 2020
Verified
Book Chapter
Open access
PDF file
JITENDRA Pal SinghJITENDRA Pal Singh
JITENDRA Pal Singh
Manish KumarManish Kumar
Manish Kumar
ASAditya Sharma
Aditya Sharma
GPGanesh Pandey
Ganesh Pandey
KCKeun Hwa Chae
Keun Hwa Chae
SLSangsul Lee
Sangsul Lee
In this chapter, we present an overview of synthesis of MgO nanoparticles and thin films by using top-down and bottom-up approaches. The bottom-up approaches are generally utilized to grow nanoparticles by the methods that involve chemical reactions. Sometimes, methods based on these reactions are also able to grow thin films. The top-down approaches are preferred for growing thin films where bulk material is used for depositions. The methods, which are frequently used, are radio frequency sputtering, pulsed lased deposition, and molecular beam epitaxy and e-beam evaporation. Sometimes, methods like mechanical milling and high energy ball milling are used to grow nanoparticles.

18 January 2022 in RSC Advances
Verified
Journal Article
Open access
PDF file
KKKanghyun Kim
Kanghyun Kim
JLJong-Won Lee
Jong-Won Lee
BPByeong-Gyu Park
Byeong-Gyu Park
HOHyun-Taek Oh
Hyun-Taek Oh
YKYejin Ku
Yejin Ku
SLSangsul Lee
Sangsul Lee
Investigations to evaluate the extreme ultraviolet (EUV) lithographic performance of 160 nm thick poly(methyl methacrylate) with 13.5 nm wavelength EUV light were performed using a synchrotron radiation source at Pohang Light Source-II (PLS-II). The single system enabled the determination of the sensitivity, contrast, linear absorption coefficient, critical dimension, and line edge roughness of polymer thin films through tests and measurements. The experimental findings were also compared to theoretical results and those of previously reported studies. According to the results of the dose-to-clear test and transmission measurements, the critical dimension of a line and space pattern (>50 nm) via interference lithography with 250 nm pitch grating agreed well with the results calculated using the lumped parameter model. The experimental results demonstrated that the equipment and test protocol can be used for EUV material infrastructure evaluation in academia and in industry.