Highly efficient non-doped single-layer blue organic light-emitting diodes based on light-emitting conjugated polymers containing trifluoren-2-ylamine and dibenzothiophene-S,S-dioxide

Abstract

A series of blue-light-emitting conjugated polymers based on electron-donating trifluoren-2-ylamine and electron-deficient dibenzothiophene-S,S-dioxide were synthesized via typical Suzuki coupling reactions. Their thermal, photophysical and electrochemical properties were fully studied. Owing to the excellent thermal stability, film-forming ability as well as the favorable energy levels of the polymers, highly efficient non-doped single-layer blue devices by using these polymers as an emitting layer (EML) were achieved. Among them, the device based on PSFOFN1 showed the highest maximum current efficiency (CEmax) of 1.99cd/A. Moreover, the device presented small efficiency roll-off with current efficiency (CE) of 1.97cd/A at high brightness up to 100cd/m2. In addition, the Commission Internationale de L’Eclairage (CIE) coordinates of all the devices are very close to the deep blue region. Our findings suggest the potential applications of the polymers in full-color flat-panel displays and organic lighting.