| 1. |
- Abdullah, Muhammad Imran, et al.
(författare)
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Quantum Chemical Designing of Efficient Sensitizers for Dye Sensitized Solar Cells
- 2013
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Ingår i: Bulletin of the Korean Chemical Society (Print). - : Korean Chemical Society. - 0253-2964 .- 1229-5949. ; 34:7, s. 2093-2098
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Tidskriftsartikel (refereegranskat)abstract
- Density functional theory (DFT) was used to determine the ground state geometries of indigo and new design dyes (IM-Dye-1 IM-Dye-2 and IM-Dye-3). The time dependant density functional theory (TDDFT) was used to calculate the excitation energies. All the calculations were performed in both gas and solvent phase. The LUMO energies of all the dyes were above the conduction band of TiO2, while the HOMOs were below the redox couple (except IM-Dye-3). The HOMO-LUMO energy gaps of new design dyes were smaller as compared to indigo. All new design dyes were strongly red shifted as compared to indigo. The improved light harvesting efficiency (LHE) and free energy change of electron injection Delta G(inject) of new designed sensitizers revealed that these materials would be excellent sensitizers. The broken coplanarity between the benzene near anchoring group having LUMO and the last benzene attached to TPA unit in all new design dyes consequently would hamper the recombination reaction. This theoretical designing will the pave way for experimentalists to synthesize the efficient sensitizers for solar cells.
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| 2. |
- Gao, Shimin, et al.
(författare)
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Synthesis, characterization, and spectroscopic properties of 2-(3,5,6-trichloro-1,4-benzoquinon-2-yl)-neo-fused hexaphyrin
- 2021
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Ingår i: Bulletin of the Korean Chemical Society (Print). - : John Wiley & Sons. - 0253-2964 .- 1229-5949. ; 42:12, s. 1569-1573
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a novel compound 2-(3,5,6-trichloro-1,4-benzoquinon-2-yl)-neo-fused hexaphyrin has been prepared from tetrachloroquinone and neo-fused hexaphyrin through a substitution reaction. The chemical structure of the compound has been characterized by nuclear magnetic resonance (NMR), high-resolution mass spectrum, UV-Vis spectrum, and X-ray diffraction. The crystal structure reveals that the quinonyl unit is almost coplanar with the adjacent N-confused pyrrole unit. Because of the cooperative effect of extended conjugation and the intramolecular charge transfer effect related to the strong electron-withdrawing character of the quinonyl unit, the absorption of 2 is dramatically extended to ca. 1280 nm.
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| 3. |
- Kim, Ji Hye, et al.
(författare)
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Study on the Dependence of Sun Protection Factor on Particle Size Distribution of Mica Using Gravitational Field-Flow Fractionation
- 2020
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Ingår i: Bulletin of the Korean Chemical Society. - : Wiley. - 0253-2964 .- 1229-5949. ; 41:1, s. 66-72
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Tidskriftsartikel (refereegranskat)abstract
- Sunlight consists of beams of light of broad wavelength ranges, including infrared, visible, and ultraviolet (UV) radiation; X-rays; and γ-rays. Although the UV content of sunlight is relatively low, the human body, especially the human skin, is sensitive to UV rays. Mica is known to be effective in protecting the human skin from sunlight and reduces fine lines and pores on the skin. Mica is currently used as a coloring agent in various sunscreen products. Still, there is no detailed report on the effect of mica on the sun protection factor (SPF). In this study, effects of the particle size, particle size distribution, and the content of mica on SPF were studied. Gravitational field-flow fractionation (GrFFF) was employed to analyze the particle size and the particle size distribution of the mica particles. GrFFF provided size-based separation of the mica particles and was useful for determining the size distributions and average sizes of the mica particles. It was found that the mixing ratio (in wt %) of 3:3:4 of TiO2:octyl methoxycinnamate:mica yielded the highest SPF. Generally, the SPF tends to increase with increasing particle size of the mica.
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