Kinetics of thermally activated triplet fusion as a function of polymer chain packing in boosting the efficiency of organic light emitting diodes

Abstract

Brighter OLEDs: role of chain packing revealed The detailed time-resolved photophysical studies stress the importance of the morphology of the polymer chains on designing high efficiency organic light emitting diodes. A collaborative team lead by Prof Dinesh Kabra from Indian Institute of Technology Bombay conducts systematic investigations on the decay kinetics and the mechanism of the delayed fluorescence in a typical F8BT based polymeric light-emitting diodes. Through time-resolved emission spectroscopy as a function of film thickness, excitation fluence, magnetic-field, and temperature, they show that the main process controlling the delayed fluorescence is thermally activated triplet-triplet annihilation. They further show that the triplet transport is highly dependent on the molecular packing order and film thickness of the F8BT polymer, opening feasible gateways for molecular engineering of polymer LEDs.