Highly Efficient Perovskite Solar Cells Based on a Zn2SnO4 Compact Layer.

In the present work, a new reflux condensation route has been developed for synthesizing a Zn2SnO4 film, which was first used as a compact layer in a perovskite solar cell (PSC) and achieved an efficiency of 20.1%. The high efficiency of PSC could be contributed to the following: (i) as a compact layer in a PSC, Zn2SnO4 exhibits high electron mobility and has an appropriate energy band structure, resulting in the efficient extraction of carriers and transport of electrons; (ii) the surface of the FTO substrate is completely covered by a Zn2SnO4 compact layer, and the direct contact between a perovskite layer and FTO is prevented, leading to a significantly efficiently suppression of charge recombination. Consequently, the cell consisting of a Zn2SnO4 compact layer exhibits excellent photovoltaic performance.