Patterning and integration of polyfluorene polymers on micro-pixellated uV alInGaN light-emitting diodes

We report the integration of micro-patterned polyfluorene conjugated polymers onto GaN-based ultraviolet (UV) micro-pixellated light-emitting diode arrays (micro-LEDs). The 64 × 64 element matrix-addressable AlInGaN devices have a pixel size of 20 µm diameter on a 50 µm pitch, emitting at 368 nm. Each array is covered with a 2.5 µm thick photo-curable deep-UV-transparent polymer and a 30 nm thick polyfluorene film. This polymer bi-layer is subsequently patterned into an array of 28 µm diameter discs aligned with the pixels of the micro-LED array. Polymer down-converted visible emission from these pattern-programmable organic/inorganic electroluminescent micro-arrays is achieved.