Ersan Y. MuslihMd. ShahiduzzamanMd. AkhtaruzzamanMohammad Ismail HossainLiangLe WangHend I. AlkhammashSami S. AlharthiMasahiro NakanoMakoto KarakawaMohammod AminuzzamanTEY, Lai-HockLai-HockTEYKamaruzzaman SopianJean-Michel NunziTetsuya Taima2024-10-182024-10-182022-01-01https://doi.org/10.35848/1882-0786/ac435dhttps://dspace-cris.utar.edu.my/handle/123456789/3314<jats:title>Abstract</jats:title> <jats:p>A nickel oxide (NiO<jats:italic> <jats:sub>x</jats:sub> </jats:italic>) hole transport layer was made from nickel oxide powder by a simple process and non-stabilizer or chelating agent. We used ethanol as the main solvent and less than 2% nitric acid as the co-solvent. The formation reaction mechanism of the NiO<jats:italic> <jats:sub>x</jats:sub> </jats:italic> thin film was also studied. Perovskite solar cells (PSCs) with an optimum thickness of 70 nm exhibited a power conversion efficiency as high as 12.99%, which is superior to those of PSCs with their counterparts. The moisture stability of NiO<jats:italic> <jats:sub>x</jats:sub>-</jats:italic>based devices (non-encapsulated) remained above 70% of their initial output after 700 h storage at ambient conditions.</jats:p>journal-article