We have designed and synthesized a new B-and N-embedded asymmetric heteroleptic phosphorescent iridium(Ⅲ)complex IrBNacac with ambipolar characteristics.The X-ray diffraction technique shows that the two B-and N-embe...We have designed and synthesized a new B-and N-embedded asymmetric heteroleptic phosphorescent iridium(Ⅲ)complex IrBNacac with ambipolar characteristics.The X-ray diffraction technique shows that the two B-and N-embeddedπ-conjugation units in the complex exhibit good planarity and induce richπ-πinteractions in the crystal state.More importantly,it exhibits an effective red emission(623 nm)in the thin film state with a very narrow full width at half maximum(FWHM=50 nm,0.158 eV),even narrower than that of model complexes(53 nm,0.162 eV for IrBBacac and 62 nm,0.224 eV for IrNNacac).DFT calculation shows that the lowest excited triplet state(T_(1))of the complex IrBNacac exhibits richer excited state characteristics than those of the model complexes,including a charge transfer transition from the N-embedded ligand to the B-embedded ligand(^(3)LLCT)and a metal-to-ligand charge transfer transition(^(3)MLCT),along with an intraligand charge transfer(^(3)ILCT).Considering the good photophysical properties and solubility,the red-emitting complex IrBNacac was used as the emitting layer of a solution-processed OLED device and showed good maximum external quantum efficiency(EQE)(4.9%)peaking at 625 nm with the CIE coordinates(0.64,0.35),accompanied by a low turn-on voltage.This research provides an important strategy for the design of narrowband red-emitting phosphorescent iridium complexes and their optoelectronic applications.展开更多
基金financial support from the National Natural Science Foundation of China(22171109 and 22001097)the Natural Science Foundation of Jiangsu Province of China(BK20201003)+1 种基金the Postdoctoral Research Foundation of China(2021M701657)the Shenzhen Science and Technology Program(KQTD20170330110107046).
文摘We have designed and synthesized a new B-and N-embedded asymmetric heteroleptic phosphorescent iridium(Ⅲ)complex IrBNacac with ambipolar characteristics.The X-ray diffraction technique shows that the two B-and N-embeddedπ-conjugation units in the complex exhibit good planarity and induce richπ-πinteractions in the crystal state.More importantly,it exhibits an effective red emission(623 nm)in the thin film state with a very narrow full width at half maximum(FWHM=50 nm,0.158 eV),even narrower than that of model complexes(53 nm,0.162 eV for IrBBacac and 62 nm,0.224 eV for IrNNacac).DFT calculation shows that the lowest excited triplet state(T_(1))of the complex IrBNacac exhibits richer excited state characteristics than those of the model complexes,including a charge transfer transition from the N-embedded ligand to the B-embedded ligand(^(3)LLCT)and a metal-to-ligand charge transfer transition(^(3)MLCT),along with an intraligand charge transfer(^(3)ILCT).Considering the good photophysical properties and solubility,the red-emitting complex IrBNacac was used as the emitting layer of a solution-processed OLED device and showed good maximum external quantum efficiency(EQE)(4.9%)peaking at 625 nm with the CIE coordinates(0.64,0.35),accompanied by a low turn-on voltage.This research provides an important strategy for the design of narrowband red-emitting phosphorescent iridium complexes and their optoelectronic applications.
