Sputtered thin film from a SnO2 target presented as ETL in a perovskite solar cells produced a S-shape JV curves. I verified the formation of SnO2 through xps and the energy levels are not that different from SnO2 nanoparticles films. Any statements about this issue? The deposition is a room temperature and 10% O2. Many thanks for any suggestions
Juan Felipe Benitez Rodriguez A thin film does not contain separate, discrete, independent particles < 100 nm. Indeed it can be argued that a thin film does not contain particles at all. It simply is a fused collection of crystallites. Different preparation conditions provide different materials with different properties. With XPS you're only looking at the top 5 - 15 atomic layers at most and all surfaces in air are fully oxidized. The bulk composition may be very different and can be examined by Ar+ ion etching the surface.
And what is the method for nanoparticles film SnO2 prepation? What is the thickness of both films, depth distribution of main elements, and interface quality?