• Rapid Communication in Photoscience
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• v.1 no.2
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• pp.41-41
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• 2012

• Rapid Communication in Photoscience
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• v.1 no.2
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• pp.48-48
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• 2012

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.251.2-251.2
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• 2013

Natural photosynthesis utilizes two proteins, photosystem I and photosystem II, to efficiently oxidize water and reduce NADP+ to NADPH. Artificial photosynthesis which mimics this process achieve water splitting through a two-step Z-schematic water splitting process using man-made synthetic materials for hydrogen fuel production. In this study, Z-scheme system was achieved from the hybrid materials which composed of hydrogen production part as photosystem I protein and water oxidizing part as semiconductor BiVO4. Utilizing photosystem I as the hydrogen evolving part overcomes the problems of existing hydrogen evolving p-type semiconductors such as water instability, expensive cost, few available choices and poor red light (>600 nm) absorbance. Some problems of photosystem II, oxygen evolving part of natural photosynthesis, such as demanding isolation process and D1 photo-damage can also be solved by utilizing BiVO4 as the oxygen evolving part. Preceding research has not suggested any protein-inorganic-hybrid Z-scheme composed of both materials from natural photosynthesis and artificial photosynthesis. In this study, to realize this Z-schematic electron transfer, diffusion step of electron carrier, which usually degrades natural photosynthesis efficiency, was eliminated. Instead, BiVO4 and Pt-photosystem I were all linked together by the mediator gold. Synthesized all-solid-state hybrid materials show enhanced hydrogen evolution ability directly from water when illuminated with visible light.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.10
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• pp.14-22
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• 2011

The artificial lights to be introduced for the plant factories is requiring the artificial light resources with minimizing the energy consumption to reduce the greenhouse gases which is a major cause of global warming, and maximizing the efficiency in photosynthesis effect light-wave range, in which the plants can be greatly grown and developed, and having the signal light-wave range for forming the light types. the best growing and developing environment for the plants has recently realized with utilizing the LED(Lighting Emitting Diode) lamps, as a environment-friendly green lamps, which can elevating the light efficiency with using only the specific light wave range. In this study, to provide the necessary lights for the full artificial light type of the plant factory, the following research/study and experiments has been conducting. experiments of the spectrum for each light sources, and LED, The intensity of illumination, Irradiance, Photosynthesis Photon Flux Density.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.280-280
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• 2013

In green plants, energy generation is accomplished through light-harvesting photosystem, which utilize abundant visible light and multi-stepwise redox reaction to oxidize water and reduce NADP+, transferring electrons efficiently with active cofactors1. Inspired by natural photosynthesis, artificial solar water-splitting devices are being designed variously. However, the several approaches involving immobilization2, conjugation3, and surface modification4 still have limitations. We have made artificial photosynthesis templates by self-assembling tyrosine-based peptide to mimick photosystem II. Porphyrin sensitizer absorbing blue light strongly was conjugated with the templates and they were hybridized with cobalt oxide through the reduction of cobalt ions in an aqueous solution. The formation of hybrid templates was characterized using TEM, and their water oxidation performance was measured by fluorescence oxygen probe. Our results suggest that the bio-templated assembly of functional compounds has a great potential for artificial photosynthesis.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.392-398
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• 2009

Artificial Asian dust was treated in this study to compare and determine its effect on growth, photosynthesis, respiration and stomata of 5 species trees. Sophora japonica's growth and respiration using artificial Asian dust treatment which is 10 times of average contents of Asian dust: $5,000{\mu}g{\cdot}m^{-2}$ decreases after 3 weeks while no significant difference in other species. The maximum photosynthesis of Sophora japonica and Betula pendula decreased significantly after 3 weeks and 6 weeks, respectively, using artificial Asian dust treatment which is average contents of Asian dust: $500{\mu}g{\cdot}m^{-2}$. At $5,000{\mu}g{\cdot}m^{-2}$ treatment, photosynthesis of both species decreased just after treatment of artificial Asian dust. Quercus acutissima, Quercus mongolica and Acer triflorum have no significant differences. Dust was found inside the Sophora japonica's stomatas under heavy dust treatment when viewed under the light electron microscope. By scanning electron microscopy, the higher rate of stomatal opening of Sophora japonica and Betula pendula was recognized and the size of both stomatas was bigger than other species. This result means that Asian dust has an influence in decreasing the photosynthesis, respiration and growth of some species especially if the stomatas are large.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.69-69
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• 2013

In the area of artificial photosynthesis, particularly for the generation of hydrogen form water, much attention has been paid on organic-inorganic hybrid system. Most of all, a dye/TiO2-combined system has been suggested and its potential utility was well manifested. However, due to its complicated nature of charge interactions in between dye and TiO2 -interface there remains a great challenge to establish the charge-activity relationship, per se light driven charge generation and recombination kinetics with respect to the amount of hydrogen produced. Further complexity of that hybrid system has been witnessed when sacrificial donor and aqueous media are considered. To unveil the operating mechanism on such a dye/TiO2-combined system, we have prepared organic dyes suitable to account for the effect of sacrificial donor as well as water interactions, and prepared the typical dye-grafted TiO2 films to investigate charge-activity relationship. Femtosecond flash photolysis clearly defined the dye effects anchored on to the TiO2 platform. In addition, photodynamic data contemplated well to the dye orientation proposed by the DFT calculations. Recent findings provide fundamental understanding on the dye-grafted TiO2 system and establish a firm background how future dye-sensitized organic-inorganic hybrid system can be designed for the light driven hydrogen generation from water.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.63-68
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• 2018

This paper presents an integrated photochemical reaction system (i.e., an artificial leaf) that uses earth-abundant catalysts for artificial photosynthesis with a carbon dioxide ($CO_2$) fixation process. The performance of the system was investigated in terms of the energy capture and conversion capabilities. A wireless configuration was achieved by directly doping cobalt oxide as an oxygen-evolving catalyst for water splitting reaction on the illuminated surface of photovoltaic (PV) cell, as well as molybdenum disulfide ($MoS_2$) as an efficient catalyst for $CO_2$ reduction on the back substrate surfaces of the PV cell. The system produces hydrogen and carbon monoxide (CO) as sustainable fuels (i.e., synthesis gas) at around 4.5% efficiency, which implies more than 75% catalytic efficiency at the cathode. The process of solar-driven $CO_2$ conversion and water-splitting reaction is contained in one system, which is one step closer to the successful realization of artificial photosynthesis.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.28 no.7
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• pp.52-58
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• 2010

• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.13-14
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• 1999