https://scholar.gist.ac.kr/handle/local/7954 2025-12-08T07:48:20Z https://scholar.gist.ac.kr/handle/local/19897 Title: Window-film Type Semitransparent Organic Photovoltaics Based on Conducting Polymer Electrodes for Building-integrated Photovoltaics Author(s): Chelim Jang Abstract: Semitransparent organic photovoltaics (ST-OPVs) with polymeric transparent electrodes are in the spotlight as window film type solar cells due to their advantages such as flexibility, high electrical conductivity, transparency, and solution processability. Currently, encouraging progress has been achieved on the ST-OPVs that focus on individual parameters such as high power conversion efficiency (PCE) and average visible transmittance (AVT), however, the passive properties as window films are yet to be explored. Furthermore, conventional transparent electrodes based on a vacuum process are expensive and possess poor productivity. Herein, we demonstrate all-solution processed multifunctional ST-OPVs using PEDOT (poly(3,4-ethylene dioxythiophene)) as a top electrode doped with perfluorinated sulfonic acid. Importantly, the perfluorinated sulfonic acid-treated PEDOT electrode exhibits high visible transmittance and outstanding electrical properties and simultaneously showed high infrared reflectance. Consequently, we successfully achieved high light utilization efficiency and thermal insulating capability. 2022-12-31T15:00:00Z https://scholar.gist.ac.kr/handle/local/19872 Title: Understanding the electrolyte/electrode interfacial interactions for the development of high-performance aqueous redox-enhanced supercapacitors Author(s): SungWon Kim Abstract: Aqueous redox-enhanced supercapacitors (redox SCs) have versatile features such as high energy, high power, non-flammability and eco-friendliness, thus have received increasing research interest. But there are obstacles to overcome such as lower energy density compared to secondary metal ion-based batteries and self-discharge issues due to cross-diffusion of dissolved redox species. In this dissertation, by quantifying the concentration of redox-active electrolytes adsorbed on the electrode surface, defined as effective concentration (i.e., maximum possible number of ions available for faradaic charging) and studying the correlation between the effective concentration and the cell level specific energy of , we optimize the performance of redox SCs. Based on the electrical energy storage mechanisms of redox SCs, the hypotheses were established and confirmed. The established hypotheses were that (1) the adsorption concentration of redox-active electrolytes is different per substituents attached to the redox core; (2) amounts of adsorbed redox-active electrolyte on the electrode affect the cell level energy performance. To confirm that, several redox-active viologen candidates (1,1′-dimethyl-4,4′-bipyridinium dibromide, EV; 1,1′-dipentyl-4,4′-bipyridinium dibromide, PV; (1,1’)-di(2-ethanol)-4,4’-bipyridinium dibromide, 2OH; (1,1’)-di(6-hexanol)-4,4’-bipyridinium dibromide, 6OH; 1,1’ -bis[3-(trimethylammonio)propyl]- 4,4’ -bipyridinium tetrabromide, NV) were synthesized and their physicochemical and electrochemical properties were tested. By using UV-Visible spectroscopy, the adsorption concentration of viologen candidates on the electrode were measured and performance of candidates was measured. Among candidates, 6OH showing excellent performance was selected as the best candidate, and through enhancing adsorption concentration step, optimized performance was measured (61.1 Wh/kgdry at 1.4 V, 0.5 A/gdry). Further the performance of 6OH with differently structured carbon electrode material (p-NOMC) was compared 2021-12-31T15:00:00Z https://scholar.gist.ac.kr/handle/local/19842 Title: Three dimensional culture of mesenchymal stem cells using porous alginate microcarriers Author(s): Jinho Kim Abstract: Mesenchymal stem cells (MSCs) are multipotent stem cells that exist in various tissues. They have self-renewal properties through dividing and the potential to differentiate into various tissues such as bone, cartilage, muscle, and fat. Because of their self-renewal and multipotent properties, MSCs are also of great interest for clinical uses. Concurrently, the importance of technology for MSCs expansion while maintaining their ability during the expansion is emerging. To this end, the microcarrier-based MSC culture method has been developed as one of the most reproducible, cost-effective, and monitorable methods as well as mass culturing of MSCs. However, conventional microcarriers have several limitations. For example, MSCs can be damaged by complex enzyme-based processes during cell recovery, and cells cannot frequently separate from microcarriers uniformly. In this study, a porous microcarrier was made of Arg-Gly-Asp (RGD) peptide-grafted alginate using thermally dissolvable agarose microbeads, which was expected to be readily dissolved by EDTA treatment for easy and high-utility mesenchymal stem cell harvest. In vitro cell culture experiments were conducted with conventional polystyrene microcarriers (Corning®) to evaluate the ability of porous alginate microcarriers to support cell expansion and to maintain stemness. The porous microcarrier did not have a significant effect on cell expansion, but it was confirmed that large pore microcarrier (LP) significantly aided maintain stemness in both adipose derived mesenchymal stem cells (ADMSCs) and placenta derived mesenchymal stem cells (PMSCs). When applied to spinner flasks using ADMSC, cell expansion was possible to a level similar to that of Corning through alginate microcarriers. Also, although the difference according to porosity disappeared, alginate microcarrier maintained significantly higher stemness compared to Corning. On the other hand, in the case of PMSC, it was confirmed that the cell number and metabolic activity were decreased by shear stress when cultured in a spinner flask, and stemness could only be maintained at a very low level compared to TCP. If the conditions of the spinner flask are optimized in the future, it is expected that there will be many clinical applications for the MSC mass culture of LP. 2021-12-31T15:00:00Z https://scholar.gist.ac.kr/handle/local/31968 Title: Therapeutic Evaluation of Subcutaneously Delivered, Alginate-Encapsulated, Genetically Engineered Mesenchymal Stem Cells for Fabry disease Author(s): Jisu Lee Abstract: Fabry disease is an X-linked lysosomal storage disorder caused by α-galactosidase A (α-Gal A) deficiency, leading to globotriaosylceramide accumulation. Current enzyme replacement therapy (ERT) requires biweekly intravenous infusions, presenting significant limitations in patient compliance and quality of life. In this study, we developed a long-term delivery system using genetically engineered mesenchymal stem cells (eMSCs) encapsulated in alginate microgels. Human α-galactosidase A-expressing eMSCs maintained high viability and stable enzyme secretion after encapsulation, and subcutaneous injection of these αGal-eMSC-Alg constructs demonstrated structural stability for up to 12 weeks in nude mice. Therapeutic efficacy in GLA knockout Fabry mice showed age-dependent outcomes, with the aged group exhibiting better trends of eMSC survival and reduced kidney Gb3 accumulation compared to the young group. This αGal-eMSC-alginate system offers single-injection, long-term therapeutic delivery advantages over conventional enzyme replacement therapy, representing a promising platform for lysosomal storage disorders with potential for optimization through further investigation of enhanced immune evasion strategies. 2024-12-31T15:00:00Z