Design, Synthesis And Optoelectronic Properties Of Ionic Organic Electroluminescent Materials

Materials used in the emitting layer should match the energy level for charge injection and should desirably possess a bipolar character, that is, have both electron-transporting (ET) and hole-transporting (HT) properties. With bipolar materials as the emitting layer, enhanced performances and operational stability have been demonstrated. Compared with the neutral one, the material with ions has many advantages, for example, it can be dissolved in a polar solvent when processing device by spin-coating, while most of the materias for the device is not soluble in such solvents.This prevents the adjacent function layers from being destroyed; At the same time, such material is usually easy perpared.In this paper triazine is used as an electron transport unit, and carbazole as the hole transport unit, quaternized or use NAN-type ligands to prepared a series of ionic organic electroluminescent light emitting materials.This paper contains the following three parts:Designed and synthesized four ionic bipolar host material with the core of triazine and the arm of carbazole.The structure of these compounds is characterized and the photophysical and electrochemical properties are studied.TFour bipolar ionic host materials2CZTRZTN+、2CZTRZHN+、2tCZTRZTN+and2tCZTRZHN+are prepared, and a series of bipolar polymer including one bipolar neutral homopolymer and five copolymers with ionic monomer are prepared. Designed and synthesized two host-guest structure ionic iridium complex2FppyIr2tCTZ and2FbpyIr2tCTZ.One ligand of these iridium complex has bipolar host unit on it, which makes them to be host-guest structure.The structures of target molecules were confirmed by1H NMR,13C NMR and MALDI-TOF-MS. Their photophysical properties, electrochemical properties and thermal stability properties had been researched by UV-Vis absorption and photoluminescence spectrum, cyclic voltaimnetry and thermogravimetric Analysis respectively. The triplet energy of these host materials are higher than2.90eV respectively, which were measured from the highest energy peak ofphosphorescence spectra at77K. The measurements showe that the two Iridium complexes emit blue-green light and can be used for the preparation of blue-green OLEDs/LECs.