| 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 | Scanning probe microscopy on Fermi levels and energy band bendings in perovskite halides |
| 초록 | Tremendous success of lead perovskite halide solar cells brings a lot of potentials for other applications like light emitting devices and resistive switching memories. Basic properties of the perovskite materials are required to understand the photon absorption and the charge transport, which are key factors for high performance optoelectronic applications [1]. We have studied the local electrical properties and surface potential distributions of two different metal-containing perovskite halides (lead and tin) via scanning probe microscopy including conductive atomic force microscopy and Kelvin probe force microscopy, respectively [2,3]. Not that tin is a promising candidate to reduce the toxicity of lead but its relatively low photo-conversion efficiency due to surface recombination is a hurdle for applications. Furthermore, optical excitation under illumination using three light sources over red, green and blue wavelengths onto the samples also supported the different nature between them. We particularly focused on the potential variations which are strongly dependent on grain boundaries and intra-grains [4]. Fermi levels pinned near the surface are altered by the illumination but the change look strongly dependent on the wavelength of the incident light. It is expected that the investigation on the movement of carriers in the perovskite thin films will have a positive effect to complement the lack of perovskite solar cells by improving the electrical quality characteristics, such as the carrier collection and recombination. [1] H. R. Jung, G. Y. Kim, B. P. Nguyen, H. J. Jin, W. Jo, T. T. T. Nguyen, S. Yoon, W. S. Woo, C. W. Ahn, S. Cho, and I. W. Kim, “Optical and Scanning-probic Identification of Electronic Structure and Phases in CH3NH3PbBr3 crystals”, Journal of Physical Chemistry C 121, 21930 (2017). [2] D. Kim, G. Y. Kim, S. R. Pae, Y. S. Lee, O. Gunawan, W. Jo, and B. Shin, “Effects of Postsynthesis Thermal Conditions on Methylammonium Lead Halide Perovskite: Band Bending at Grain Boundaries and Its Impacts on Solar Cell Performance, Journal of Physical Chemistry C 120 (2016). [3] B. P. Nguyen, G. Y. Kim, W. Jo, B. J. Kim, and H. S. Jung, “Trapping charges at grain boundaries and degradation of CH3NH3Pb(I,Br)3 perovskite thin-films”, Nanotechnology, 28, 315402 (2017). [4] G. Y. Kim, S. H. Oh, B. P. Nguyen, W. Jo, B. J. Kim, D. G. Lee, and H. S. Jung, “Efficient Carrier Separation and Intriguing Switching of Bound Charges in Inorganic−Organic Lead Halide Solar Cells”, Journal of Physical Chemistry Letters, 6, 2355 (2015). |
| 저자 | William Jo |
| 소속 | Department of Physics |
| 키워드 | <P>perovskite; scanning probe microscopy</P> |
