Vertical composition and morphology analysis of high performance perovskite solar cells

• Main Authors: Yu-Pei Yang, 楊諭佩
• Other Authors: Chun-Wei Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/50657707945970945609

碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 103 === Organic-inorganic hybrid perovskite materials have been successfully applied as light absorbers in photovoltaic cell, which boost rapidly in power conversion efficiency, up to 20%. According to the recent researches, the power conversion efficiency of perovskite solar cell depends on the quality of perovskite film significantly. In this study, we used two-step deposition method to fabricate organic-inorganic hybrid perovskite solar cells. We found that conversion ratios of CH3NH3PbI3 were influenced by controlling various concentration of CH3NH3I precursor solution. Therefore, three perovskite films with different conversion ratios were prepared to discuss the relationship between the crystallinity, morphology, chemical composition of perovskite films and photovoltaic performance of perovskite solar cells, respectively. Interaction between an extended three-dimensional network of PbI6 octahedral and CH3NH3I is demonstrated by XRD and XPS measurement. Moreover, we used XRD analysis at various incidence angles to observe the crystallization of perovskite films in vertical direction, to understand how the composition of perovskite in vertical distribution impacts on perovskite solar cell. Finally, we propose the conversion mechanism of perovskite. In addition, different orientations of crystal planes were first observed between the surface and the interior of PbI2 films. Crystal planes tend to arrange in single orientation on the surface of PbI2 films, while crystal planes in the interior are non-directional due to effect of TiO2 scaffold layer. Furthermore, similar orientations of crystal planes were also observed on the surface and in the interior of converted CH3NH3PbI3. Thus, these findings indicated that CH3NH3PbI3 grow along PbI2.