Pyridine substituted spirofluorene derivative as an electron transport material for high efficiency in blue organic light-emitting diodes

The quantum efficiency of blue fluorescent organic light-emitting diodes was enhanced by 20% using a pyridine substituted spirofluorene–benzofluorene derivative as an electron transport material. 2′,7′-Di(pyridin-3-yl)spiro[benzofluorene-7,9′-fluorene] (SPBP) was synthesized and it was used as the electron transport material to block the hole leakage from the emitting layer. The improvement of the quantum efficiency and power efficiency of the blue fluorescent organic light-emitting diodes using the SPBP was investigated.