Highly efficient deep blue light emitting devices based on triphenylsilane modified phenanthro[9, 10-d]imidazole



Highly efficient deep blue fluorescent material (SiPIM) based on phenanthro[9, 10-d]imidazole (PPI) and triphenylsilane is designed and synthesized. SiPIM presents a narrow deep blue emission, high quantum yield, high thermal stability and good morphological stability. A non-doped vacuum-deposited device using SiPIM as active layer achieves an extremely high external quantum efficiency of 6.29% with true deep blue CIE coordinates of (0.163, 0.040). The solution-processed device is also tried due to the good solubility of SiPIM, which displays a maximum ηext of 2.40% and CIE coordinates of (0.157, 0.041).