Design of hierarchically meso–macroporous tetragonal ZrO2 thin films with tunable thickness by spin-coating via sol–gel template route

Hierarchically meso–macroporous tetragonal ZrO2 (t-ZrO2) thin films with tunable thickness were prepared by spin-coating method via Pluronic P123 templated sol–gel route. This hierarchically porous ZrO2 was characterized by field-emission scanning electron microscope, atomic force microscope, nitrogen adsorption–desorption isotherm, X-ray diffraction, and ultraviolet–visible spectrometer. Effects of rotation speed and by coating another layer of sol on the first layer during spin-coating on the thickness and mesoporous structure of ZrO2 thin films formed were investigated. The meso–macroporous ZrO2 film coated on a glass substrate possessed an average transmittance higher than 80% in the visible range. It was suggested that the structure of Pluronic P123 was changed as concentration of deposited sol varied over time, which led to the formation of worm-like mesospores coexisted with macropores and rod-like ZrO2 framework. Formation of cracks on ZrO2 thin films was initiated by the structure of meso–macropores and shrinkage of respective films.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Hierarchically meso–macroporous t-ZrO2 thin films were prepared by spin-coating via Pluronic P123 templated sol–gel route. ► Increasing rotation speed during spin-coating decreased surface roughness and oxide thickness. ► By coating second layer of ZrO2 film, surface roughness of respective film decreased slightly and the thickness increases. ► Mesostructures of ZrO2 film are disordered worm-like mesopores coexisted with macropores.