Hazy Al(2)O(3)-FTO Nanocomposites: A Comparative Study with FTO-Based Nanocomposites Integrating ZnO and S:TiO(2) Nanostructures

In this study, we report the use of Al(2)O(3) nanoparticles in combination with fluorine doped tin oxide (F:SnO(2), aka FTO) thin films to form hazy Al(2)O(3)-FTO nanocomposites. In comparison to previously reported FTO-based nanocomposites integrating ZnO and sulfur doped TiO(2) (S:TiO(2)) nanoparticles (i.e., ZnO-FTO and S:TiO(2)-FTO nanocomposites), the newly developed Al(2)O(3)-FTO nanocomposites show medium haze factor H(T) of about 30%, while they exhibit the least loss in total transmittance T(tot.) In addition, Al(2)O(3)-FTO nanocomposites present a low fraction of large-sized nanoparticle agglomerates with equivalent radius r(eq) > 1 μm; effectively 90% of the nanoparticle agglomerates show r(eq) < 750 nm. The smaller feature size in Al(2)O(3)-FTO nanocomposites, as compared to ZnO-FTO and S:TiO(2)-FTO nanocomposites, makes them more suitable for applications that are sensitive to roughness and large-sized features. With the help of a simple optical model developed in this work, we have simulated the optical scattering by a single nanoparticle agglomerate characterized by bottom radius r(0), top radius r(1), and height h. It is found that r(0) is the main factor affecting the H(T)(λ), which indicates that the haze factor of Al(2)O(3)-FTO and related FTO nanocomposites is mainly determined by the total surface coverage of all the nanoparticle agglomerates present.