Serious environmental problems have been caused by the greenhouse effect due to carbon dioxide(CO2) or nitrogen oxides(NOx) generated by the use of fossil fuels, including oil and liquefied natural gas. Many countries, including our own, the United States, those of the European Union and other developed countries around the world; have shown growing interest in clean energy, and have been concentrating on the development of new energy-saving materials and devices. Typical non-fossil-fuel sources include solar cells, wind power, tidal power, nuclear power, and fuel cells. In particular, organic solar cells(OSCs) have relatively low power-conversion efficiency(PCE) in comparison with inorganic(silicon) based solar cells, compound semiconductor solar cells and the CIGS [Cu(In1-xGax)Se2] thin film solar cells. Recently, organic cell efficiencies greater than 10 % have been obtained by means of the development of new organic semiconducting materials, which feature improvements in crystalline properties, as well as in the quantum-dot nano-structure of the active layers. In this paper, a brief overview of solar cells in general is presented. In particular, the current development status of the next-generation OSCs including their operation principle, device-manufacturing processes, and improvements in the PCE are described.

Ocjective : Sabaeksan has been used for the purpose of prevention and treatment of bronchial asthma and allergic asthma in korea. Methods : To investigate the biological effect of Sabaeksan, the author examined cytotoxicity and inflammatory cytokines secretion with human leukemic mast cell line, HMC-1. HMC-1 was stimulated with phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187. Sabaeksan by itself had no effect on viability of HMC-1. Result : The effects of Sabaeksan on the secretion of tumor necrosis factor-alpha (TNF- α) and interleukin (IL)-6 from HMC-1 were evaluated with enzyme-linked immunosorbent assay. Sabaeksan (1 ㎎/㎖) inhibited PMA plus A23187-stimulated TNF-α and IL-6 secretion, by 43.86 ± 5.26%, 56.39 ± 3.65%, respectively. Sabaeksan also inhibited the NF-κB (p50/p65) expression. Conclusion : Taken together, these results suggest that Sabaeksan inhibit the production of inflammatory cytokines in HMC-1 cells through blockade of NF-κB activation.