Sub-400 nm ultra-violet luminescence of (4´-methoxy)-9-phenylcarbazole

Intense ultra-violet photoluminescence at 380 nm (3.26 eV) was observed from a small organic molecule, (4´-methoxy)-9-phenylcarbazole (MeOKPA) at room temperature. The intensity is at least three times of that of Alq₃, which is most widely used for organic LED application. Excitation spectrum and low temperature photoluminescence (PL) results show that the shortest emission is at 360 nm (3.44 eV). The small stoke shift of 180 meV from excitation to emission indicates that the radiative recombination of MeOKPA is extremely efficient and the compound is robust over a wide temperature range. Moreover, it also has strong upconversion efficiency. Its upconversion PL is a little different from normal PL. The result indicates that it is a strong candidate as organic laser.