Effect of the functional inorganic material nickel oxide synthesized by solution method on the photoelectric performance of perovskite solar cells

Functional inorganic material nickel oxide (NiO_x) as one of the most promising hole transport materials in perovskite solar cells, it has the advantages of high hole mobility, good stability, easy processing and suitable Fermi level. However, due to the inherent low conductivity of NiO_x itself, the ionization energy of Ni vacancies is quite large, and the hole density in undoped NiO_x is greatly restricted. In addition, the accumulation of holes increases the possibility of carrier recombination, thereby reducing the effective charge collection. Therefore, opti-mizing the quality of NiO_x film formation is the key to solving the above problems. In this paper, DME-NiO_x, EA-NiO_x and NCs-NiO_x films were prepared by solution method using ethylene glycol methyl ether (MEA), ethanol (EA) and deionized water as solutions. And optimized the NiO_x-based perovskite device within the concentration adjustment range. In the end, the best device with a photoelectric conversion efficiency (PCE) of 18.50%, an open circuit voltage (V_oc) of 1.034 V, a short circuit current (J_sc) of 22.94 mA/cm² and a fill factor (FF) of 78% is obtained.