| 학회 | 한국재료학회 |
| 학술대회 | 2018년 봄 (05/16 ~ 05/18, 삼척 쏠비치 호텔&리조트) |
| 권호 | 24권 1호 |
| 발표분야 | 7. 차세대 태양에너지 재료 및 디바이스(Emerging Solar Energy Materials and Devices)-오거나이저: 신병하 교수(KAIST) |
| 제목 | Mixed valence perovskite Cs2Au2I6: a potential material for thin-film Pb-free photovoltaic cells with ultra high-efficiency |
| 초록 | Due to unprecedented improvements in photoelectric conversion efficiency, halide perovskite solar cells are considered one of the most promising next-generation photovoltaic technologies. However, two inherent limitations are known for widely used organic-inorganic hybrid perovskite solar cells; low material stability presumably due to the presence of organic components, and high toxicity due to the presence of lead. This has led many researchers to find a stable and harmless alternative. However, to date, lead-free inorganic perovskite materials, which have been investigated computationally and/or experimentally so far, often have at least one of the problems of low photo conversion efficiency, poorer stability, and difficulty of synthesis. As an alternative, we suggest an old-but-novel inorganic perovskite of Cs2Au2I6, which was previously experimentally synthesized but not applied to photovoltaic cells. Interestingly, Cs2Au2I6 exhibits mixed valent properties yielding two different oxidation states of Au centers (I and III). Due to this exotic character, Cs2Au2I6 behaves like a so-called double perovskite, while it is a single perovskite in terms of elemental composition. The main advantage of Cs2Au2I6 as the solar cell material is emphasized by the optimum bandgap size of c.a. 1.3eV close to the Shockley-Quiesser value, and by the direct bandgap characteristic which allows highly efficient absorption of light even at very thin film thicknesses. Using a state-of-the-art multiscale simulation connecting from the quantum-mechanical level of simulation to the large-scale of electromagnetic wave simulation, it is further shown that the advantageous photophysical property of Cs2Au2I6 can be maintained even in polycrystalline form, and can be successfully transferred to device level with very high photoelectric conversion efficiency. |
| 저자 | Hyungjun Kim |
| 소속 | Department of Chemistry and Graduate School of EEWS |
| 키워드 | . |
