KOSEN 한인과학기술자네트워크

Research

Our research goal is developing novel materials for energy applications with the current emphasis on non-toxic, earth-abundant, and low-cost
compounds for photovoltaic and photocatalytic applications.

Inorganic-organic hybrid perovskite solar cells have brought a wave of attention to the field of photovoltaics, already reaching extraordinary efficiencies of above 22% comparable to those of high-efficiency silicon solar cells. Also, perovskite has high color purity and easy tunability at visible light range. Through these properties, it is can be a promising light emitter. Due to their low exciton binding energy (~50 meV), However, excitons in perovskite layers are easily dissociated by thermal energy, consequently leading to luminescence quenching. To resolve this, we focus on low dimensional structures of halide perovskite that can confine excitons.

• Perovskite Solar cells

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• Perovskite Light Emitting Diodes

Cu(In,Ga)Se2 (CIGS) is a leading thin film PV technology which exhibits power conversion efficiencies over 22%. Also since CIGS is a potential of BIPV applications, we are researching low temp CIGS and Cd free buffers. Additionally, to realize mass deployment of a PV technology economically, PV devices must exhibit high efficiencies and consist of materials that are earth-abundant and non-toxic. The kesterite Cu2ZnSn(S,Se)4 (CZTSSe) compound has emerged as a potential candidate to reach this goal. We are working on improving the performance of SnS (SnSe) and Sb2S3 (Sb2Se3) as well. Additionally, we are exploring thermoelectric properties of SnSe.

• CIGS

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• CZTS Solar Cells

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• Sb2Se3 Solar Cells

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• SnSe Thermoelectric

Photoelectrochemical Water Splitting

A promising and environmental-friendly way of producing renewable energy is photoelectrochemical (PEC) water splitting, where the sun light and semiconducting materials are used to decompose water into hydrogen and oxygen gases. The traditional material for this purpose is TiO2 but its large bandgap (~3.0 eV) poses a severe limitation in terms of efficient utilization of the solar spectrum. As an alternative to TiO2, we are working on developing Cu(In,Ga)Se2 photocathodes for hydrogen evolution and BiVO4 photoanodes for oxygen evolution; by connecting them in tandem configuration, we aim to build PEC cells for unassisted (i.e. no applied bias) photocatalytic water splitting.

• Photocathode for hydrogen evolution reaction(CIGS)

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• Photoanode for oxygen evolution reaction(BiVO4)