Visible-light photoelectric performance of RMnO3 (R = La, Pr and Nd) epitaxial films with structural distortion

All-inorganic perovskite has aroused extensive attention as the light absorption layer of solar cells due to the high photoelectric conversion efficiency and chemical stability. In this work, RMnO3 (RMO, R = La, Pr and Nd)/(001) LaAlO3 (LAO) epitaxial films were prepared by the polymer assisted deposition method. All of the RMO films were grown epitaxially with tetragonal distortion (like Jahn-Taller distortion) of MnO6 octahedron. Owing to lattice mismatch between RMO and LAO, the tetragonal distortion of MnO6 octahedron increases when the radius of trivalent R ions increases. This reduces the crystal field splitting energy of MnO6 octahedron, resulting in a reduction in the band gap and enhancement of the visible-light photoelectric performance. It also reveals that the surface-adsorbed oxygen plays a crucial role in the photoelectric process of the RMO epitaxial films. More surface-adsorbed oxygen, existing in RMO films with larger R ions, can enhance the double exchange of electrons in Mn3+ - O2- - Mn4+, thus preventing the recombination of photogenerated electron-hole pair and improving the photoelectric performance. These results provide a channel to tune the structure and photoelectric performance of perovskite manganese oxide.

Automated summary

All-inorganic perovskite has attracted extensive attention as the light absorption layer of solar cells due to its high photoelectric conversion efficiency and chemical stability. This study found that the structure and photoelectric performance of perovskite manganese oxide can be tuned by adjusting lattice mismatch and surface-adsorbed oxygen content.