Synthesis and photophysical properties of 1,2-diphenylindolizine derivatives: fluorescent blue-emitting materials for organic light-emitting device.

New blue-emitting materials based on 1,2-diphenylindolizine were designed and synthesized through a microwave-assisted Suzuki coupling reaction. The photophysical, electrochemical, and thermal properties of the 1,2-diphenylindolizine derivatives were investigated using UV-visible and fluorescence spectroscopy, cyclic voltammetry, thermogravimetric analysis, and differential scanning calorimetry. The 1,2-diphenylindolizine derivatives had band gaps of 3.1-3.4 eV and indicated proper emission of around 450 nm without significant difference between in solution and thin solid film. The indolizine derivatives show an enhanced thermal stability (∆Tm > 100 °C), compared with 1,2-diphenylindolizine. These results suggest the 1,2-diphenylindolizine derivatives are suitable for blue-emitting materials in organic light-emitting devices.