| 학회 | 한국재료학회 |
| 학술대회 | 2016년 가을 (11/16 ~ 11/18, 경주 현대호텔) |
| 권호 | 22권 2호 |
| 발표분야 | C. 에너지 재료 분과 |
| 제목 | Enhancement of Hole Extraction in Br- Gradient Perovskite Light Absorber Materials |
| 초록 | Perovskite solar cells, based on state-of-the-art light absorbing inorganic-organic halide perovskite materials, have shown remarkable progress on account of achieving power conversion efficiencies greater than 22%. Due to their poor humidity-, photo-, and thermal-stability, mixed halide perovskite materials have been briskly researched. Especially, halide gradient perovskite materials have been expected to enhance the hole extraction rate because the valence band level of perovskite materials is modified in a gradational manner. However, as far as we know, the halide concentration gradient perovskite materials have not been realized due to the difficulty in developing synthetic techniques. In this study, we report the fabrication of Br concentration gradient mixed halide perovskite materials using a novel and facile halide conversion method based on vaporized hydrobromic acid. We observe the great hole extraction property of Br concentration gradient perovskite layer by steady-state Photoluminescence measurement. By using depth profiling and compositional analysis, the diffusion behavior of bromide ions was monitored. The halide gradient was found to be eventually converted into a homogenous mixed halide layer after undergoing an intermixing process. This facile method exhibited the enhancement of perovskite solar cell performance including PCE and long-term stability, via halide doping. Especially, Longterm stability was dramatically enhanced after the Br substitution process, i.e. the PCE of the post-treated device has remained over 97% of the initial value under high humid condition (40-90%) without any encapsulation for 4 weeks. This study claims that the fume substitution method using HBr is capable of controlling Br substitution spatially, which enables realizing halide gradient as well as achieving higher efficiency and humidity-stability. This is the first step for fabricating the halide gradient in the mixed halide perovskite layer. |
| 저자 | 김병조, 김원빈, 이상명, 정현석 |
| 소속 | 성균관대 |
| 키워드 | <P>Perovskite solar cell; Halide substitution; Halide concentration gradient; Steady-state <BR>photoluminescence; Secondary ion mass spectroscopy</P> |
