Synthesis of well dispersed NiO ink for efficient perovskite solar cells

NiO ink fabricated perovskite solar cells (PSCs) is attracting increasing attention due to the simple preparation process and the low processing temperature. Ascribing to the easy aggregation property of the nanoparticles, it is quite important to fabricate high quality NiO ink with high crystallinity and good dispersity. In this work, the function of the anions to the nanoparticles (NPs) formation is discussed. It is found out that suitable electrostatic interactions between the NO3− and Ni2+ lead to high crystallinity and well dispersion of the NiO NPs. The high quality NiO ink fabricated by Ni(NO3)2 results in high quality NiO HTL and perovskite on it. The perovskite solar cell device using Ni(NO3)2 fabricated NiO HTL exhibits performance of 18.4% with good reproducibility and stability, much higher than 16.3% of PSCs with NiCl2 fabricated NiO layer. This work highlights an anion influenced NiO NPs' formation process, which is quite illuminating to the fabrication of high performance PSCs.