The optimal film morphology of perovskite thin film is a prerequisite for highly efficient perovskite solar cells. The conventional one-step or two-step solution casting for perovskite thin films usually suffer from relatively small domain size with increased bulk defect sites at grain bounday. Recently, efficient perovskite solar cells have been demonstrated using hot-casting technique which can grow continuous and pinhole-free perovskite thin film with enlarged grain size. However, hot-casting technique usually suffers from non-uniform film morphology with high surface roughness which results in low device performance and poor reproducibility. In this work, we demonstrate that the organic ammonium chloride significantly improves the film morphology of low band gap perovskite layer from hot-casting. The additive affords uniform thin films with pinhole-free large domains morphology, which results in increased photocurrent and photovoltage generation. The influence of additives on optical, morphological and device performance of the low band gap perovskite from hot casting will be discussed.

Additive engineering of low bandgap perovskite from hot-casting process for high efficiency perovskite solar cells

2019 Fall National Meeting

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