is an aromatic solvent in one embodiment the organic liquid is selected from chloroform dichloromethane toluene anisole and mixtures thereof the hole transport material can be present in the liquid medium in a concentration of 0 2 to 2 percent by weight other weight percentages of hole transport material may be used depending upon the liquid medium the hole transport layer can be applied by any continuous or discontinuous liquid deposition technique in one embodiment the hole transport layer is applied by spin coating in one embodiment the hole transport layer is applied by ink jet printing after liquid deposition the liquid medium can be removed in air in an inert atmosphere or by vacuum at room temperature or with heating in one embodiment the layer is heated to a temperature of 300 u00b0 c or less in one embodiment the heating temperature is between 170 u00b0 c and 275 u00b0 c in one embodiment the heating temperature is between 170 u00b0 c and 200 u00b0 c in one embodiment the heating temperature is between 190 u00b0 c and 220 u00b0 c in one embodiment the heating temperature is between 210 u00b0 c and 240 u00b0 c in one embodiment the heating temperature is between 230 u00b0 c and 270 u00b0 c the heating time is dependent upon the temperature and is generally between 5 and 60 minutes in one embodiment the final layer thickness is between 5 and 50 nm in one embodiment the final layer thickness is between 5 and 15 nm in one embodiment the final layer thickness is between 15 and 25 nm in one embodiment the final layer thickness is between 25 and 35 nm in one embodiment the final layer thickness is between 35 and 50 nm.