Present day electronic devices are enabled by design and implementation of precise interfaces that control the flow of charge carriers. Solution-processed organometallic perovskite based solar cells have emerged as a promising thin-film photovoltaic technology. Here, I will describe a novel solution-processed technique to grow high quality large-area mm-scale perovskite crystals leading to highly efficient (18%) and reproducible solar cells with reduced defect induced recombination. Theoretical simulations rationalize specifics of electronic structure of these materials, presence of interfacial states, bimolecular recombination rates and reduced losses of carriers. Ensuring photo-stability over prolonged solar irradiation a key challenge in these materials. We observe the photo-degradation and fast self-healing of the photocurrent in perovskite solar cells under constant illumination. We attribute the photocurrent degradation to the formation of light-activated meta-stable trap states. Experimental characterization and theory suggest their origin to the formation of localized charged states strongly coupled with local structural lattice distortions and methyl ammonium (MA) quasistatic configurations. Overall, our results provide insight towards the material design for efficient and photo-stable perovskite solar cells.

On the way toward efficient perovskite photovoltaics

251st National Meeting (2016)

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