Enhancing efficiency of perovskite solar cells from surface passivation of Co doped CuGaO nanocrystals.

Before completely applying inorganic materials as hole transport materials (HTM) for perovskite solar cells (PSCs), modifying devices with inorganic oxides that have the potential as inorganic hole transporters is an effective way to improve device performance and stability. Co doped CuGaO nanocrystals (Co-CuGaO NCs) with sizes about 20 nm are synthesized by hydrothermal method and used for surface passivation at the interface of perovskite (PVK)/2,2',7,7'-Tetrakis[N,N-di (4-methoxyphenyl) amino]-9,9'-spirobifluorene (spiroOMeTAD). Co-CuGaO NCs have a larger bandgap with lower valance band compared with spiroOMeTAD, which is more beneficial to the conduction of holes and the blocking of electrons.

Toward Highly Reproducible, Efficient, and Stable Perovskite Solar Cells via Interface Engineering with CoO Nanoplates.

It is well-known that solution-processed polycrystalline perovskite films show a high density of parasitic traps and the defects mainly exist at grain boundaries and surfaces of polycrystal perovskite films, which would limit potential device performance by triggering the undesired recombination and impair device long-term stability by accelerating the degradation of perovskite films. In this regard, defect passivation is highly desirable for achieving efficient and stable perovskite solar cells (PSCs). Here, we report the fabrication of highly reproducible, efficient, and stable PSCs via interface engineering with CoO nanoplates.