EFFICIENT WHITE EMITTING COPOLYMERS BASED ON BIPOLAR FLUORENE-co-DIBENZOTHIOPHENE-X,X-DIOXIDE-co-CARBAZOLE BACKBONE

• Published in: 高分子科学：英文版 no. 1; pp. 88 - 97
• Main Author: Lei Ying Yan-hu Li Cai-hong Wei Min-quan Wang Wei Yang Hong-bin Wu Yong Cao
• Format: Journal Article
• Language: English
• Published: 2013
• Subjects: 二氧化物; 二苯并噻吩; 双极; 发光聚合物; 合作; 咔唑基团; 白光; 白色发光二极管
• ISSN: 0256-7679; 1439-6203

Efficient white light emitting polymers were synthesized based on poly（9,9-dioctylfluorene-co-dibenzothiophene- S,S-dioxide） as blue emitter and a bisphenylamine functionalized 2,1,3-benzothiadiazole （DPABT） as red emitter. It was found that the incorporation of hole-transporting carbazole moiety into polymer main chain could effectively reduce the hole injection barriers, which can lead to distinctly improved charge balance in the emissive layer. Additionally, the hole- transporting carbazole units may form efficient bipolar host with electron-transporting dibenzothiophene-S,S-dioxide units. The white light emitting diodes based on single polymer PFSOCzDPABT showed the maximum luminous efficiency of 3.3 cd/A with the maximum luminance of 10282 cd/m2, and the luminous efficiency showed only 24% roll off at current density of 400 mA/cm2. These Commission Internationale d＇Enclairage （CIE） coordinates of the devices changed slightly with the driving voltages increasing from 8 V to 12 V, and were very close to National Television System Committee （NTSC） standard white light emission of （0.33, 0.33）. The results indicated that the incorporating bipolar host and low band gap DPABT unit was a promising way to achieve efficient single white light emitting copolymers.