Paper EH-WeE9
Correlating Local Morphology and Local Opto-Electronic Properties of Hybrid Organic-Inorganic Perovskite Solar Cell Materials

Wednesday, December 10, 2014, 8:20 pm, Room Lehua

We demonstrate an in-depth characterization of local opto-electronic properties in hybrid organic-inorganic perovskite materials for solar cells using complementary scanning probe techniques.

Perovskite solar cells have the potential to combine high efficiency and low-cost fabrication compared to other third-generation solar technologies; Since 2009, power conversion efficiency of perovskite solar cells has rapidly increased from 3.8% to almost 20%. However, one of the main challenges to systematically increase power conversion efficiency and to develop cost efficient fabrication techniques is the lack of understanding of the exact operating mechanism in perovskite solar cells. In particular, the relationship between morphology, chemical composition, and optoelectronic processes and their impact on overall performance in these materials is hardly understood.

We have studied two promising solution processed hybrid organic-inorganic perovskite materials, CH₃NH₃PbI₃ and CH₃NH₃PbI_3-xCl_x, using scanning probe techniques to determine local photocurrent generation, topography, and the local electronic structure. Depending on composition and fabrication approach, we observed substantial differences in local morphology, crystallinity, photocurrent generation, and photoluminescence. Specifically, we have measured a significant heterogeneity in the local photocurrent generation that does not correlate with topography but rather with the local electronic structure.