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영어로 읽는 과학기사 A Korean research team has developed core technology for new-concept solar cells.
The Ministry of Education, Science and Technology(Ahn Byung-man, Minister) said on June 4 that a Korean research group had developed core technology for production of a new structure solar cell, which integrates the technological characteristics of conventional solar cells. The new technology, which is an integrated type that combines organic and inorganic materials, is raising expectations because it allows for the production of next-generation solar cells that boast long durability and high efficiency.
The study was spearheaded by a research team led by Dr. Seok Sang-il at the Korea Institute of Chemical Technology, and conducted jointly with a research team led by Prof. Graetzel at the Federal Institute of Technology Lausanne in Switzerland. The study was conducted with support from the Global Research Laboratory Assistance Program run jointly by the ministry and the Korea Research Foundation(Park Chan-mo, Chairman). The study was published as a distinguished paper in the early online edition (May 28) of Nano Letters, a scientific journal on nano materials/devices. The researchers also applied for patent in Korea and overseas.
Integrating advantages of existing solar cells
Examples of conventional solar cell technologies include an inorganic semiconductor thin film solar cell, which is highly efficient but expensive; a dye-sensitized solar cell, which is relatively efficient and cheap to produce but raises long-term safety concerns; and an organic solar cell, which is cheap to produce but is low in optical stability.
Inorganic semiconductor thin film solar cell
If solar light with an energy volume larger than that of the Band-gap Energy(Eg) of the semiconductor is beamed in when inorganic semiconductor thin films of electron (n) and electron hole(p) are integrated into the p-n form, electron-electron hole pairs are created. The inorganic semiconductor thin film solar cell operates through a mechanism in which the electrons of these electron-electron hole pairs are gathered in the n layer, while electron holes are collected in the p layer due to the electrical field created in the p-n interface. While highly efficient, it has the disadvantage of being expensive to produce.
Dye-sensitized solar cell
This solar cell copies the principle of photosynthesis in plants. It operates by causing electron-electron hole pairs created through the absorption of solar light to separate in the electron conductor-hole conductor interface by applying a dye that absorbs solar light onto electron(n)-conducting frames, and thus driving electrons and holes to flow via the external circuit. This is relatively efficient and cheap to produce, but entails safety concerns in long-term use due to its employment of liquid electrolyte.
Organic solar cell
This solar cell is produced by integrating materials that can absorb electrons with a copolymer material that generates electron-electron holes by absorbing solar light This is cheap to produce, but has the shortfall of low optical stability. Dr. Seok Sang-il's research team introduced into the dye-sensitized solar cell structure the advantages of the inorganic semiconductor thin film solar cell, which is expensive but highly efficient, and those of the cheap-to-produce organic solar cell. |
Based on the dye-sensitized solar cell structure, the research team utilized a method in which they used inorganic semiconductors of highly efficient, inorganic semiconductor thin film solar cells by converting them into nanoparticles(including quantum dots) as a photo-active sensitizer in lieu of dye, and effectively integrated them with the copolymer of organic solar cells. For the study, the research team used a material for inorganic semiconductor nanoparticles, which costs pennies per gram, instead of a synthetic dye, which costs hundreds of dollars per gram.
The study has allowed for the production of solar cells through a process of integration between a low-cost inorganic material and chemical liquid, and has made possible solar energy absorption both in inorganic semiconductor nanoparticles and conducting copolymer, as well as the conversion thereof into electrical energy. Additionally, it can utilize solar light energy in the near-infrared light spectrum, and will likely be easily applied to large surface or flexible circuit boards.
In explaining the significance of his study, Dr. Seok of the Korea Research Institute of Chemical Technology said, "The technology is a new-concept solar cell that integrates the advantages of the inorganic semiconductor thin film solar cell, which is known as a next-generation solar cell technology, organic solar cells, and dye-sensitized solar cells," adding, "This is a fundamental technology that boasts double benefits of high efficiency and low cost."
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저작권자 2010.07.13 ⓒ ScienceTimes
