摘要
The realization of highly efficient devices depends on efficient charge carrier injection, employment of materials, and proper fabrication methodologies. However, it is difficult to manufacture highly efficient large-area devices due to the varied thickness of organic layers and low mobility of charge carriers. Solution and thermal evaporation processes have been reported for the fabrication of highly efficient and long-lifetime organic light-emitting diodes (OLEDs). This work reveals appropriate performance enhancement by employing solution-processable nanocomposite, i.e., titanium oxide (TiO2) nanoparticles embedded in 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) as an electron-transport layer with high electron mobility and good compatibility with the yellow emissive layer. Topographies of TiO2-doped TPBi films with different doping concentrations are observed after annealing at 60 °C. The device using a 20 wt % TiO2-doped TPBi exhibits maximum power efficacy of 56.1 lmW-1, current efficiency of 53.9 cdA-1, and external quantum efficiency of 15.4%, while that without TiO2 nanoparticles showed values of 37.0 lmW-1, 35.1 cdA-1, and 10.8%, respectively. The enhancement may be attributed to improved electron mobility, efficient hole-blocking, and reduced barrier height. The solution-processable TiO2-doped TPBi may lead to an efficient fabrication strategy for next-generation lighting and display applications.