We present a new, simple method to improve internal light out coupling of organic light emitting diodes (OLED) by incorporating the micro- and nano- islands or network structures in the device. These structures were fabricated by a self-assembly technique based on the deliquescence of Cesium Chloride (CsCl) salt. The size and type of structures can be controlled by varying the CsCl film thickness, relative humidity, developing time and temperature. The fabricated structures can be used as a mask to transfer to Tungsten trioxide (WO3) hole injection layer by using thermal evaporation deposition. The light emitting performance of the WO3 patterned OLEDs was investigated. The maximum improvement of luminance efficiency of the WO3 patterned OLEDs can reach up to 76% for islands structures and 92% for networks structures compared with an unpatterned OLED.