The Magnetic Filed Effect of the Singlet Fission and Triplet-Triplet Annihilation Reactions in Polycrystalline Tetracene-Based Diodes

We characterize the magneto photocurrent (MPC) response in polycrystalline tetracene-based diodes and magneto photoluminescence of the tetracene film and attribute the initially decreasing and then increasing MPC responses to the feature of the singlet fission (SF) reaction. The SF reaction in polycrystalline tetracene active layer is more evident when the device was irradiated with the short wavelength of irradiation. This observation indicates a possible route to utilize the excess exciting energy for the generation of extra excited states (triplet) to contribute the higher photocurrent. Additionally, through the measurement of magneto electroluminescence of tetracene-based diodes operated under the forward bias regime, we are able to characterize the reaction of triplet-triplet annihilation (TTA) to singlet. The TTA process may harvest the energy from triplet to singlet excitons in tetracene active layer and in part contribute the emission to fluorescence especially in the high current density and low temperature regime.