Phosphorescent cationic iridium complexes with phenyl-imidazole type cyclometalating ligands: A combined experimental and theoretical study on photophysical, electrochemical and electroluminescent properties

作者：He, Lei^*; Wang, Zhen; Yang, Chunpeng; Duan, Lian^*; Tang, Ruiren; Song, Xiangzhi; Pan, Chunyue

来源：Dyes and Pigments, 2016, 131: 76-83.

DOI：10.1016/j.dyepig.2016.04.006

• Phosphorescence
• Cationic iridium complexes
• Phenyl-imidazole
• Light-emitting electrochemical cells

Phosphorescent cationic iridium complexes with phenyl-imidazole type cyclometalating ligands have been synthesized for the first time and their photophysical, electrochemical properties have been comprehensively investigated. By changing the ancillary ligands, the complexes give orange-red or green-blue light. Compared to 2-phenylpyridine (ppy), the phenyl-imidazole ligands destabilize simultaneously the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals of the complexes. Their emitting triplet states show dominant charge-transfer (iridium/cyclometalating ligands -> ancillary ligands) character. The complexes have been used to fabricate solid-state light emitting electrochemical cells (LECs). The orange-red LEC gives a high peak current efficiency of 14.3 cd A(-1), which is among the highest reported for orange-red LECs; the green-blue LEC gives a peak current efficiency of 6.3 cd A(-1). It is shown that the phenyl-imidazole cyclometalating ligands hold promise for the invention of iridium-based cationic phosphorescent dyes with tunable energy levels and emission properties.

• 出版日期2016-8
• 单位中南大学; 清华大学