Effect of interfacial mixed layer in blue phosphorescent organic light‐emitting diodes

Blue phosphorescence organic light‐emitting diodes (PHOLEDs) with interfacial mixed layer (IML) were fabricated to observe their electrical characteristics. The IML was composed of mCP as host material in the emissive layer (EML) and 3TPYMB as material for the electron transport layer (ETL) with the blue phosphorescent dopant FIrpic. PHOLEDs with IML were improved by 41% of current density and 35% of luminous efficiency compared to PHOLEDs without IML. The electron and energy transition mechanisms between EML and ETL in the presence of IML were confirmed through I–V–L characteristics and blue color coordinates.