Date : 2013. 12. 5, 4:30 PM Place : Mogam Hall, Bldg.500 -Abstract- A quantum dot (QD) is a semiconductor crystal with the size on the order of the Bohr radius of the exciton, typically few to tens of nanometers. Strong quantum confinement of QDs causes discrete energy levels and wider band gaps compared to the bulk semiconductors, providing promising opportunities for optoelectronic applications. Especially colloidal QDs are based on low temperature synthesis and provide solution-processing, compatible with low-cost, large-area, and flexible devices. Lead chalcogenide (PbS, PbSe, PbTe) QDs have unique properties such as large Bohr radii and tunable gaps in near infrared region, which promises broad applications in field-effect transistors, bio-imaging, LEDs, thermoelectrics, photodetectors, and photovoltaic devices. Especially increasing demand for sustainable and green energy supply has driven research on next generation photovoltaics such as organic solar cells or dye-sensitized solar cell. Colloidal QD solar cell is a new type of photovoltaic device using QD film as absorber material, without high temperature and vacuum-based deposition process.