Controllable synthesis of three-dimensional hierarchical porous ZnO film with mesoporous nanowalls

Controllable synthesis of hierarchical porous semiconductors films is highly desirable for high-performance electronics and optical devices. Herein, we report a facile hydrothermal synthesis method to fabricate three-dimensional hierarchical porous ZnO film on conductive substrate. The obtained ZnO film exhibits a net-like porous architecture with hierarchical porosity from mesoporosity to macroporosity. Interestingly, the ZnO film possesses mesoporous walls ranging from 2–5 nm. Besides, the as-prepared ZnO film also shows a high specific surface area of ∼237 m2 g−1 and a noticeable porosity up to 76%. A growth mechanism is also proposed. The developed strategy can be extended to the fabrication of other hierarchical porous metal oxides for applications in solar cells, gas sensors and thin-film batteries.

Graphical abstractHydrothermal-synthesized ZnO film has the combined properties of hierarchical porosity from mesoporosity to marcoporosity and high surface area.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Hierarchically porous ZnO film is prepared via a hydrothermal synthesis method. ► Porous ZnO film possesses mesoporous walls. ► ZnO film shows high surface area and porosity.