| Tremendous attention has been aroused to phosphorescent organic light emitting diodes (PhOLEDs) because of their capability of capturing both singlet excitions and triplet excitions. While phosphorescent polymeric light emitting diodes (PhPLEDs) have higher thermal stability and better film-forming ability than PhOLEDs. Because of this, spin-coating and ink-jet priting are widely used to fabricate PhPLEDs, which are cheaper than thermal evaporation under high vacuum. In order to efficiently confine the electro-generated excitons in the emitting layer, the introduction of the host materials is indispensable. However the development of blue PhPLEDs is lagging behind, due to the lack of efficient polymeric host materials. Blue PhPLEDs play an important role in full colour flat panel displays. So it is vital to development polymeric host materials.In this paper, two kinds of polymers as phosphorescent polymeric hosts were synthesized successfully. One of them is a diphenyl oxide thiophene based polysiloxane (PDBTSi). Another is an alternating copolysiloxane based bipolar hosts (PCz-alt-DBTSi) with diphenyl oxide thiophene and phenylcarbazole.The research results of this paper is as follows:1. PDBTSi displays a high decomposition temperature (Td=396?), good film-forming ability, fine transparency and high morphological stability. But its triplet energy level (ET=2.54 eV) is lower than FIrpic (ET=2.62eV).2. PCz-alt-DBTSi exhibits a high decomposition temperature (Td= 426?), good film-forming ability,fine transparency and high morphological stability. It also exhibits a high triplet energy level (ET= 3.0 eV). A FIrpic-based host material (PCz-alt-DBTSi) exhibits a turn-on voltage of 6.4 V, maximum power efficiency of 0.45 1m·W-1, maximum current efficiency of 0.91 cd·A-1.These results show it is a promising methods that using polysiloxane to modify small molecule fluorophores to improve the physical properties without changing other properties. |
PDF Full Text Request