Adhesion layer for solution-processed transition metal oxides on inert metal contacts of organic thin film transistors.

摘要

The invention relates to the use of an ammonium thio-transition metal complex as an adhesion promoter for immobilising temperature-stable transition metal oxide layers on an inert metal surface. An example is provided where ammonium thio-transition metal complex comprises a transition metal from molybdenum, tungsten or vanadium. An example of an ammonium thio-transition metal is ammonium tetrathiomolybdate. Examples of suitable transition metal oxides are MoO3, WO3 or V2O5. Also, the formation of the transition metal oxide involves the use of a precursor of the transition metal oxide being deposited on the inert metal surface, whereby the precursor is a dispersion or a dissolution of the transition metal oxide, transition metal oxide hydrate, ammonium salt of an acidic transition metal oxide hydrate otr phosphoric acid transition metal oxide complex in water or a phosphoric acid transition metal oxide dissolved in a polar organic solvent. An example of a transition metal oxide deposited by this method is MoO3, WO3 or V2O5 The deposition of the precursor can take place by means of spin-coating, dip-coating or inkjet printing. The inert metal can be gold, copper or silver. The transition metal oxide layer deposited is reported to be stable to at least 140oC. A process for the forming of the metal oxide is also disclosed which involves the pre-treating of an inert thio-transition metal complex, depositing a solution comprising a transition metal oxide precursor onto the pre-treated surface and annealing the deposited solution to form a layer of transition metal oxide. The invention is particularly suited to organic thin film transistors whereby the source and drain electrodes comprise an inert metal.