Organic vapor jet printing at micrometer resolution using microfluidic nozzle arrays

Organic vapor jet printing with a print head comprised of a microfluidic Si nozzle array is used to deposit parallel lines of an organic semiconductor thin film with a line width of 16 μm16 μm and edge resolution of 4 μm4 μm. Line width and feature size are functions of process conditions, depending strongly on nozzle-to-substrate separation distance. Experimental results are accurately characterized by a direct simulation Monte Carlo model. The model suggests that feature sizes of <1.5 μm<1.5 μm are attainable by this printing process. The ability of the print head to codeposit doped films is demonstrated by growing the emissive layer of a green phosphorescent organic light emitting diode sandwiched between hole and electron transport layers deposited by vacuum thermal evaporation. This device had an external quantum efficiency of 8.8±1.3%8.8±1.3%, comparable to a similar device entirely grown by vacuum thermal evaporation.