Reproducible, low cost methods for synthesis of highly complex nano-materials are a requisite for any large scale application in any of the areas of renewable energy.Solution based processing routes allowing for multi-phase, multi-elemental nano-materials are probably the best suited for achieving this.With the increasing level of knowledge on band-structure engineering the requirements now includes the possibility to efficiently prepare coatings with a desired phase and content of less than 4-5 nm thickness.