Electroluminescent properties of organic light emitting diodes using Zn(HPB)2 and Zn(HPB)q

Recently, high luminance and efficiency have been realized in the OLEDs with multilayer structure including the metal-chelate complexes as the emitters. In this study, new electroluminescence materials, namely, [2-(2-hydroxyphenyl)benzoxazole] (Zn(HPB)2), and [2-(2-hydroxyphenyl)benzoxazole(8-quinoline)] (Zn(HPB)q) are synthesized and used in the OLEDs. Both of the materials are low molecular compound with good thermal stability. The ionization potential (IP) and electron affinity (EA) of Zn(HPB)2 and Zn(HPB)q were measured by cyclic-voltammetry (CV). Basing on the consideration of matched in the energy levels of the materials. We also used Zn(HPB)q as electron transport layer and Zn(HPB)2 as hole blocking layer. Through the experiments, it is demonstrated that Zn(HPB)q is also good an electron transport material and Zn(HPB)2 is also good a hole blocking material.