Highly efficient green organic light-emitting devices based on terbium complex by employing hole block material as host

摘要

In this work,efficient green electroluminescent(EL)devices with simplified device structure were prepared by doping trivalent terbium complex Tb(PMIP)_3into hole block material Tm Py PB.The high triplet energy of Tm Py PB helps to confine excitons within light-emitting layer,while the electron transport characteristic of Tm Py PB facilitates the balance of carriers on Tb(PMIP)_3molecules.By optimizing the doping concentration of Tb(PMIP)_3and the thickness of each functional layer,highly efficient green EL device with the structure of ITO/Mo O_3(3 nm)/TAPC(50 nm)/Tb(PMIP)_3(30 wt%):Tm Py PB(25 nm)/Tm Py PB(60 nm)/Li F(1 nm)/Al(100 nm)displayed pure Tb^(3+)characteristic emission with maximum current efficiency,power efficiency and brightness up to 47.24 cd/A(external quantum efficiency(EQE)of 14.4%),43.63 lm/W and 1694 cd/m^2,respectively.At certain brightness of 100 cd/m^2,the device still maintained a current efficiency of 19.96 cd/A(EQE=6.1%).Such a device design strategy helps to improve the EL performances of Tb(PMIP)_3and to simplify device fabrication processes,thus reduce the fabrication cost.