It has been demonstrated that phenothiazine unit (M2) is a excellent p-type building block for lowering IP (ionic potential) of conjugated polymers due to its readily injection and transport of hole.Unlike phenothiazine

phenothiazine-5-oxide (M3) is a specific molecular which may be a good electron transporting unit due to the conversion of electron-donating sulfur atom to electron-withdrawing sulfoxide group.M3 was synthesized successfully through five-step reaction including: (1) nucleophilic substitution alkylation of initial material phenothiazine

(2) Vilsmeier reaction of the above product

(3) protection of aldehyde group

(4) oxidation of sulfur to sulfoxide and (5) hydrolysis of acetal.Using the hole transport property of M2 and the electron transport property of M3

we synthesize a high efficient electroluminescent polymer[P1]

meantime the two units have the nonplanarity charateristic of molecular structures which can impede π-stacking aggregation and intermolecular excimer formation to improve the quantum efficience of P1.Aflexible long chain is fused on the phenothiazine ring to improve the solubility of polymer in furan

chloroform

toluene.To investigate the effect of electron-withdrawing of phenothiazine-5-oxide on the electron transport characteristic

polymer (P2) which doesn’t contain phenothiazine-5-oxide unit is synthesized with the same method as P1.For comparison

P1 and P2 are fabricated into single layer devices

and the external quantum efficiency of P1 device is 2.5 times more than that of P2 device.It implies that the introduction of M3 effectly improve the luminescent efficiency of P1.