Synthesis of phosphine oxides with tris(benzoxazole/benzothiazole) moieties and their OLED characteristics

Abstract

ABSTRACTWe have developed a series of phosphine oxides with heterocycles for the light-emitting materials of various colors. In this study, we report novel phosphine oxides with tris(benzoxazole/benzothiazole) moieties, such as (4-(benzo[d]thiazol-2-yl)phenyl)phosphine oxide (4-TBTPO) and tris(4-(benzo[d]oxazol-2-yl)phenyl)phosphine oxide (4-TBOPO). The cyclization reactions were carried out from 4,4′,4″-phosphoryltribenzoic acid and 2-aminobenzenethiol or 2-aminophenol with tetrabutylammonium bromide and triphenyl phosphite as catalysts. The structures and thermal properties were investigated by 1H-NMR, 13C-NMR, FT-IR, UV-Vis, TGA and DSC. The OLED devices of ITO/MoOx(30 nm)/NPB(600 nm)/4-TBTPO or 4-TBOPO(200 nm)/Alq3(300 nm)/Liq(10 nm)/ Al(120 nm) showed yellow-green emissions at (0.429∼0.529) and (0.406∼0.563) of CIE color coordinates, respectively.