Flexible Encapsulation of Organic Light-Emitting Diode Using the LiF/polymer/LiF Buffer and Metal Foil

New simple and reliable encapsulation using the inorganic/organic/inorganic buffer and metal foil was studied on a red phosphorescent organic light-emitting diode (PhOLED) for flexible electronics. The LiF/polymer(AZ1512-photoresist)/LiF and Cu foil were used as the materials of the inorganic/organic/inorganic layers and a metal cover in the configuration of encapsulation, respectively. To make the process simple in the fabrication of red PhOLED, bis(10-hydroxybenzo[h]quinolinato)beryllium (Bebq(2)) was used in common as a host material of emissive layer and an electron transporting material of electron transport layer. The fabricated device before encapsulation showed a maximum quantum efficiency of 15.3%, color coordinates of (0.67, 0.32) and a luminance of 5,100 cd/m(2) at 8V. Luminance change was little found in the process of flexible encapsulation. Luminance degradation of the device encapsulated with the buffer layers of LiF/AZ1512-photoresist/LiF and Cu foil according to the passage of time was very stable during a long term after one week and comparable to that of the device encapsulated with a conventional glass lid.