Efficient Molecular Organic Light-Emitting Diodes Based on Silole Derivatives

摘要

We report the performance of molecular organic light-emitting diodes (MOLEDs) using silole derivatives as emissive and electron transport materials. Two siloles, namely 2,5-di-(3- biphenyl)-1,1-dimethyl-3,4- diphenylsilacyclopentadiene (PPSPP) and 1,2-bis(1-methyl-2,3,4,5,- tetraphenylsilacyclo pentadienyl)ethane (2PSP), with high PL quantum yields of 94% and 85%, respectively, were used as emissive materials. Another silole, namely 2,5-bis-(2' 2'-bipyridin-6- yl)-1,1-dimethyl-3,4- diphenylsilacyclopentadiene (PyPySPyPy), was used as the electron transport material. MOLEDs using these two siloles and NPB as the hole transport material show a low operating voltage of approximately 4.5 V at a luminance of 100 cd/m2 and high external electroluminescence (EL) quantum efficiencies of 3.4% and 3.8%, respectively, at 100 A/m2. MOLEDsbased on PPSPP exhibit a red-shifted EL spectrum which is assigned to anexciplex formed at the PPSPP:NPB interface.