High-efficiency organic light-emitting diodes based on ultrathin blue phosphorescent modification layer

Zhu Yun-Ke, Zhong Jian^†, Lei Shu-Ying, Chen Hui, Shao Shuang-Shuang, Lin Yu

(color online) (a) Luminance–current density–voltage, (b) current efficiency–power efficiency–current density, and (c) normalization EL spectra of devices A1–A5.