“…18,19 Recently, solution-processed transition metal oxides (TMOs), such as Molybdenum oxide (MoO 3 ), Vanadium oxide (V 2 O 5 ), Germanium dioxide (GeO 2 ), and nickel oxide (NiO), have been widely used in OSCs for avoiding the acidic nature of the aqueous PEDOT:PSS dispersions. [20][21][22][23][24][25][26][27][28][29] As predicted, most TMO-based OSCs exhibited prolonged lifetime compared to those PEDOT:PSS based devices. However, the detailed degradation mechanisms related to the hole interfacial layer are not yet well understood.…”