EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Nanoporous metal oxides and composites are of high interest for many scientists in the field of electronics, optics and catalysis due to their precisely adjustable properties. By functionalizing the pore walls with another metal oxide species, promising core-shell oxide-oxide systems are produced combining the high specific surface area and good accessibility of the pore surface with enhanced synergetic material properties due the high interface area of the given metal oxide materials. One possibility of producing these composite materials is atomic layer deposition (ALD) which enables controlled monolayer growth of various metals, oxide and chalcogenides on highly complex substrates. However, temperatures above 200 °C frequently used for producing metal oxide films via ALD are disqualifying flexible, but temperature-sensitive polymers to be coated with these composite materials.
In this study, we provide a procedure to overcome this issue by using a transfer technique to produce a mesoporous composite material with a large interface area of TiO2-CeO2 on a polycarbonate (PC) substrate. While mesoporous TiO2 thin films provide a distinct porous structure with spherical-shaped mesopores of around 14 nm, CeO2 represents a challenging ALD oxide due the required high temperatures and necessity of ozone as co-reactant during the deposition process. The transfer is investigated by XRD, XPS, ToF-SIMS, SEM and ellipsometry. Furthermore, stress and bending measurements are performed.
With the presented method transparent plastic materials with elastic properties and low densities can be coated for further investigations of metal oxide thin films, core-shell structures and composite materials. The representative system of TiO2-CeO2 allows studying the influence of the oxygen storage properties and the change of the band gap on its catalytic and photocatalytic properties. The usage of multiple different substrates enables other investigation methods and new applications for science and for the development of further metal oxide devices on flexible plastic substrates.