Electroplex emission from bilayer LED based on 1-phenyl-3-(dimethyl-amino) styryl-5-(p-(dimethylamino) phenyl) pyrazoline and 2,2′-(2,5-thiophenediyl) bis-(5-phenyl)-1,3,4-oxadiazole

The photoluminescence (PL) and electroluminescence (EL) properties of a novel organic compound, 2,2′-(2,5-thiophenediyl) bis-(5-phenyl)-1,3,4-oxadiazole (TOXD), were studied as electron transporting material. The PL emission maximum peak is at 408 nm of TOXD in chloroform and is at 472 nm in solid film, respectively. The EL emission maximum peaks of the bilayer ITO/PDP/TOXD/Al LED located between emission maximum peaks of TOXD (470 nm) and PDP (500 nm) at lower driving voltage, 4.5–5.4 V, and shifted to 508 nm at 6.0 V and 518 nm at 7.0 V with increase of applied voltage. The new EL emission peak at 518 nm from the bilayer LED is ascribed to electroplex formation at the interface of TOXD and PDP film in bilayer LED under external electric field. The electroplex emission is close to the energy levels of PDP and TOXD.