Modular Synthesis of Polybenzo[b]silole Compounds for Hole-Blocking Material in Phosphorescent Organic Light Emitting Diodes

A diversity-oriented synthetic strategy allowed us to design a series of conjugated molecules containing multiple benzosilole units that can be utilized as efficient hole-blocking materials for phosphorescent organic light emitting diodes (OLEDs). Some of these compounds showed a performance surpassing that of the current standard, bathocuproine. The new compounds were easily synthesized in a modular fashion from a previously reported 3-stannyl benzosilole building unit. Studies on the properties of these compounds in solution and in the solid state indicate that they possess high electron affinity, high ionization potential, and form stable amorphous films that show high electron-drift mobility. The correlation between their molecular properties and the efficiency of the OLED device performance is also investigated.