Repository Collection:http://repository.sungshin.ac.kr/handle/2025.oak/1542026-05-19T15:13:34Z2026-05-19T15:13:34ZMachine Learning Driven Energy Transfer Prediction in Mn-Doped 2D Halide Perovskites조준상Seonhong MinSeyeon ParkDoyun KimSeong Wook Hwanghttp://repository.sungshin.ac.kr/handle/2025.oak/88562025-12-29T00:41:24Z2025-07-16T15:00:00ZTitle: Machine Learning Driven Energy Transfer Prediction in Mn-Doped 2D Halide Perovskites
Author(s): 조준상; Seonhong Min; Seyeon Park; Doyun Kim; Seong Wook Hwang
Abstract: Manganese (Mn2+) metal doping into lead halide perovskite has offered an expanded palette to tailor the optoelectronic properties through engineering the energy transfer between the energy donor (exciton) and energy acceptor (Mn2+). However, it still remains a challenge to precisely modulate the two different emission centers to achieve the desired optoelectronic properties due to the presence of a complex interplay of competing excited-state dynamics, involving exciton recombination, forward and backward energy transfer, and dopant-state recombination. Here, we have developed a machine learning (ML) driven predictive framework to elucidate the complex energy transfer seen in Mn(x)-doped 2D PEA2Pb(Br1–yIy)4 perovskites. With integration of the ML predictive modelwith time-resolved spectroscopy, we identify and prioritize key important features (closely associated with excitonic properties such as bandgap, full width at half-maximum (FWHM), and wavelength), governing the degree of Mn sensitization. The ML-driven approach not only allows for precise prediction of desired optoelectronic properties but also uncovers nonlinear structure–function correlations that are often overlooked by conventional approaches. Our study, thus, provides new insight into the doped system, paving the way for the rational design of next2025-07-16T15:00:00ZSurface Reconstruction in Quasi-2D Perovskite Films Treated with Cesium Halide Nanocrystals: Halide Exchange or Phase Transformation조준상손동일민선홍안소현이동렬이세현김동한송명훈김진영박성욱박종남http://repository.sungshin.ac.kr/handle/2025.oak/88272025-12-30T01:54:36Z2025-07-06T15:00:00ZTitle: Surface Reconstruction in Quasi-2D Perovskite Films Treated with Cesium Halide Nanocrystals: Halide Exchange or Phase Transformation
Author(s): 조준상; 손동일; 민선홍; 안소현; 이동렬; 이세현; 김동한; 송명훈; 김진영; 박성욱; 박종남
Abstract: The formation of heterostructure interfaces from quantum dots (or nanocrystals) and
lower-dimensional (2D or quasi-2D) materials enables interfacial and optoelectronic
property tuning. However, this strategy has not been sufficiently characterized, for
example, the application of cesium halide nanocrystals to quasi-2D perovskite
structures is underexplored, and the mechanisms of the resulting structural modifications
and specific nanocrystal roles are not fully understood. Herein, the effects
of postsynthetically surface-modifying quasi-2D perovskite films with CsX (X =Cl,
Br, I) nanocrystals are examined to bridge this gap. The purposeful choice of X
enables the selective induction of halide exchange or a structural phase transformation
at the nanocrystal–perovskite interface, which leads to optical bandgap and
luminescence property modulation over a wide range of the visible spectrum
(450–620 nm). Results of in situ spectroscopic analyses and temperature-dependent
kinetic studies reveal that the activation energy for the halide exchange
(24–29 kJ mol1) is lower than that for the structural phase transformation to 0D
Cs4PbX6 nanocrystals (39 kJmol1), indicating the kinetic favorability of the former
process. The potential of the developed strategy is showcased through the fabrication
of efficient color-tunabl2025-07-06T15:00:00ZUnveiling Mechanistic Origins of Enhanced Cycling Performance in Quasi-Solid-State Batteries with High-Concentration Electrolytes신민정이다은http://repository.sungshin.ac.kr/handle/2025.oak/88212025-12-29T00:40:45Z2025-02-13T15:00:00ZTitle: Unveiling Mechanistic Origins of Enhanced Cycling Performance in Quasi-Solid-State Batteries with High-Concentration Electrolytes
Author(s): 신민정; 이다은
Abstract: All-solid-state lithium metal batteries are promising candidates for next-generation batteries. However, they face challenges due to poor interfacial properties between the solid electrolyte and electrode. In this study, to address these interfacial issues, a small amount of high-concentration liquid electrolyte (HCE), consisting of lithium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane, is incorporated between the solid electrolyte and Li metal to create a quasi-solid-state electrolyte (QSE) battery. Electrochemical measurements show that the QSE cell achieves a critical current density of ∼10 mA cm–2 and exhibits enhanced Li plating/stripping reversibility with uniform Li morphology. The mechanistic origins of this improved electrochemical performance of the QSE system were systematically investigated. We propose that HCE positively influences the interface by alleviating contact gaps and forming a LiF-rich inorganic solid electrolyte interface. Additionally, the QSE cell effectively mitigates contact loss from localized current and void formation, providing insights for designing favorable interfaces in solid-state battery systems.2025-02-13T15:00:00ZEnhancing the Multifunctional Photocatalytic Activity of Sustainable Magnetic Nanoparticles신민정김영훈박은별황선영홍정아장재혁김영민http://repository.sungshin.ac.kr/handle/2025.oak/88032025-12-30T01:44:41Z2025-05-10T15:00:00ZTitle: Enhancing the Multifunctional Photocatalytic Activity of Sustainable Magnetic Nanoparticles
Author(s): 신민정; 김영훈; 박은별; 황선영; 홍정아; 장재혁; 김영민
Abstract: The development of efficient photocatalytic materials has intensified in response to increasing emphasis on sustainable energy conversion and environmental restoration. However, the excessive use and indiscriminate release of heavy metals from photocatalytic nanoparticles pose potential environmental risks. This study provides insights into optimizing visible-light-active photocatalysts to enhance their photocatalytic properties and stability. Specifically, cobalt doping and controlled pH modulation are employed on the modified Fe3O4, forming two distinct samples: Co@Fe3O4-B (base-treated) and Co@Fe3O4-A (acid-treated) nanoparticles. Microscopic characterization reveals that Co@Fe3O4-A undergoes a phase transition to hematite, whereas Co@Fe3O4-B retains its mixed-phase configuration. Spectroscopic analyses confirm that the cobalt dopants decorate the outskirts of each nanoparticle, forming a core–shell structure. However, Co@Fe3O4-B exhibit Co2+ states with a high oxygen vacancy content, whereas Co@Fe3O4-A contain mixed Co2+/3+ states. The high density of defect states in the Co@Fe3O4-B results in superior photocatalytic efficiency, achieving near-complete oxidation of furfuraldehyde (97% conversion) and 5-hydroxymethylfurfural (94% conversion), as well as effective degradation of toluene (78% conversion). This2025-05-10T15:00:00Z