Process‐Friendly and Long‐Lasting ZnO Powder as an Electron Transport Material for High‐Performance Solar Cells

The extensive utilization of inorganic electron‐transporting layers (ETLs) in organic solar cells (OSCs) has steered interest toward their potential commercialization. Though both organic and inorganic ETLs generally require solution processing or synthesis, the poor stability of inorganic ETLs restricts them to unsustainable and unfeasible single‐use applications. To address this limitation, it is critical to develop inorganic ETL materials that not only support solution processing but also offer stable storage and a simple synthesis route suitable for commercialization. In this study, we developed a novel method for solidifying inorganic‐based organic complexes derived from sol–gel processes, which allows for a shelf‐stable product, hereby enabling commercial scalability. By modulating the polarity of a sol–gel‐derived zinc oxide solution with organic functional groups, we produced a solidified nanocomposite that exhibits excellent stability. Due to the removal of reactive residues, the powder form of zinc oxide (PZO) exhibits excellent film‐forming properties along with superior electrical and optical characteristics as an ETL. The use of PZO as an ETL in OSCs with a structure of ITO/poly(3,4‐ethylenedioxythiophene) (PEDOT:PSS)/PBDB‐T‐2F:BTP‐4F (PM6:Y6)/interfacial layer/Al increased the power conversion efficiency from 13.83% to 16.45%. Furthermore, PZO showed prolonged reliability in both the material and the device.