Abstract: The present invention addresses uniformly formed layers on TCOs with minimized thickness which are hole transporting, due to a hole transport material which is configured for self assembly on the corresponding surface. The layers are formed by a compound made up of at least one kind of molecule according to formula (I) mixed up with a filler molecule FM given by where L is a linking fragment, A an anchor group and HTF is a hole transporting fragment. FM (filler molecule) is at least one kind of molecule consisting of an anchoring group, an alkyl chain of N carbon atoms, with N is in the range of 1 to 18, and a functional group of at least on of the group methyl, halogen, amino, bromide, ammonium and sulfuric functional group and where x is in the range of 0.02 to 1 and y equals (1-x).