Syntheses of efficient nickel oxide film by low-temperature fabrication technique for high-performance perovskite solar cells

Interface modification is an effective technique to improve power conversion efficiency (PCE) of perovskite solar cells (PSCs). In this study, three kinds of hole transport layers (HTLs), including planar-nickel oxide (P-NiOx) film, surface-nanostructured-NiOx (S-NiOx) film, and modified-NiOx (M-NiOx) film, are synthesized by low-temperature fabrication technique. Furthermore, M-NiOx film is defined by modifying P-NiOx film with ultra-low concentration NiOx nanoparticles. The results show that the M-NiOx film has higher conductivity and carrier transport ability than those of P-NiOx and S-NiOx. The special morphology of M-NiOx film is beneficial to improving the crystallinity of MAPbI3 perovskite film. Thus, the PSC based on M-NiOx film exhibits the highest short-circuit current density (Jsc) of 21.30 mA cm−2, which is larger than those of PSCs based on P-NiOx (17.74 mA cm−2) and S-NiOx films (16.56 mA cm−2). The optimized PSC based on M-NiOx film exhibits the high photovoltaic performance with PCE of 16.67%. The optimized PSC with M-NiOx film shows a long-term stability. After storing in a nitrogen-filled glove box for 1000 h, the PSC with M-NiOx film still has 85% of its initial PCE.