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4시 20분부터 제1과학관 31214 e+강의실에서 다과를 준비하오니 많은 참석 부탁드립니다.

아 래

Title: Next-generation solar cells for high photo-conversion efficiency

 
Speaker: Prof. William Jo  (Department of Physics, Ewha Womans University)

Date & Time: Dec. 2(Wed.) 2015, 4:30 PM

Place: Natural Science 1,  Room No. 31214

Abstract: In this talk, we will review our recent results on next-generation solar cells: Cu2ZnSn(S,Se)4 (CZTSSe) and organic-inorganic lead halide perovskites. CZTSSe absorber materials were grown by stacked sputtering method and subsequently annealed in H2Se atmosphere in a furnace. We changed stacking order and thickness of all metal-based precursors of CZTSSe thin-films to reduce the secondary phases and improve the solar cell efficiencies. The photo-conversion efficiency of the CZTSSe cells showed 12.3%, which is the best results among the vacuum deposition methods. To chase with efficiency of CuInGaSe2 solar cell, we explored the secondary phase issues of CZTSSe thin-film solar cells. For this study we performed the phase characterization of CZTSSe thin-film with different depths by using Raman scattering spectroscopy and Kelvin probe force microscopy with depth profiles [1]. On the other hand, we fabricated a mesoporous perovskite solar cell with high conversion efficiencies (>15%), and we investigated its beneficial grain boundary properties of the perovskite solar cells through the use of scanning probe microscopy. The surface work function and the local current were measured using Kelvin probe force microscopy and conductive-atomic force microscopy, respectively. The CH3NH3Pb(I,Br)3 improved the potential barrier at the grain boundary and induced passivation. We also investigated the polarization and hysteretic properties of the perovskite thin-films by measuring the local piezo-response [2].

[1] G. Y. Kim, D.-H. Son, T. T. T. Nguyen, S. Yoon, M. Kwon, C. Jeon, D.-H. Kim, J.-K. Kang, and W. Jo, “Enhancement of photo-conversion efficiency in Cu2ZnSn(S,Se)4 thin-film solar cells by control of ZnS precursor-layer thickness”, Progress in Photovoltaics: Research and Applications (in press).

[2] G. Y. Kim, S. H. Oh, B. P. Nguyen, W. Jo, B. J. Kim, D. G. Lee, 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).