1. Eco-friendly and earth abundant Cu-Zn-Sn-S-Se (CZTSSe) solar cells

    Silicon, GaAs, and Cu(In,Ga)(Se,S)2 (CIGS) solar cells have been actively studied in recent decades for use as an eco-friendly energy source. Among the single junction solar cells, crystalline silicon, group III–V GaAs, and CIGS solar cells showed a high power conversion efficiency (PCE) of 26.7%, 28.8%, and 21.7%, respectively. However, to promote the use of solar cells, the fabrication process should ultimately use earth abundant elements without toxic materials. The deposits of rare metals such as In or Ga are limited, and As is toxic. Hence, in recent years, CZTSSe solar cells that use earth-abundant elements without toxic materials have been studied.

2. Flexible metal mesh/ITO hybrid transparent electrodes

    Flexible optoelectronic devices such as solar cells, light-emitting diodes (LEDs), and photodetectors have been actively studied in recent years for wearable devices and/or biomedical applications. Most commercial electronic devices use indium tin oxide (ITO) thin films which have high performance and chemical durability as a transparent electrode. However, their bending stability is markedly low because of their rigid and brittle properties, and to improve this, several studies have reported hybrid transparent electrodes that combine the advantages of varied materials. We herein demonstrate a flexible hybrid transparent electrode combining metal mesh and ultrathin ITO (uITO) on colorless polyimide (CPI) film.

3. Flexible CZTSSe solar cells fabricated using transfer method or metal foil substrate.

    Flexible high-efficiency CZTSSe solar cells are one of the outstanding research challenges because they currently require the use of thick glass substrates due to the high-temperature heat treatment process, and for this reason, few flexible CZTSSe solar cells have been reported. Furthermore, most researchers have used thin glass and metal substrates with little flexibility and the power conversion efficiencies (PCEs) of the solar cells made with them have been somewhat lower. To overcome these hurdles, we transferred high-efficiency CZTSSe solar cells formed on a soda-lime glass substrate to flexible substrates via an adhesive-bonding transfer method.

4. Current project

Research for Ultra Lightweight High-performance Flexible Thin-Film Solar Cells

    Sponsor: GIST Research Institute (GRI)
    Project Leader: Kyung-Pil Kim

Development of thin photovoltaic module over 25% efficiency based on micro solar cells for mobile applications

    Sponsor: Korea Institute of Energy Technology Evaluation and Planning (KETEP)
    Project Leader: Kyung-Pil Kim