Employing ambipolar oligofluorene as the charge-generation layer in time-of-flight mobility measurements of organic thin films

Strong absorption of oligofluorenes at wavelengths of a few commonly used nanosecond pulsed lasers, their bipolar transport characteristics, and high mobilities for both holes and electrons make them useful as the general and effective charge-generation material for the time-of-flight mobility measurement of organic materials. In this letter, we demonstrate the use of the terfluorene as the charge-generation material for measuring hole and electron mobilities of various organic materials. Such a scheme has the advantages of simplifying the instrumentation and reducing material consumption in the measurements.