Evaluation of Plamsonic Enhancement and Quenching of Ag Nanoparticles in Organic Light-Emitting Diode

The utilization of localized surface plasmon (LSPR) to improve the yield of organic light emitting diode (OLED), has been subject of numerous publications and reports. Several enhancement mechanisms have been highlighted such as the increase of Förster energy transfer, the enhancement of the OLED electroluminescence as well as the increase of the current I and the decrease of the turn-on voltage V [1,2]. Nevertheless, these mechanisms are still not completely studied and understood. One major problem of using metallic NPs is the inherent losses associated with their conductivity. Another important issue concerns the evaluation of their electrical and optical effects on the total yield enhancement. Besides, the LSPR wavelength and the distance of the metallic NPs from the OLED emitting layer (EML) are very important parameters for a maximum enhancement of the near-field-induced energy transfer between excitons and NPs LSPR. In fact, LSPR modifies the radiative and the non-radiative decay rates of adjacent emitters resulting in two competitive processes: the fluorophores radiation intensity enhancement and the non-radiative quenching of activated fluorophores on the NP metal surface. To obtain an overall enhancement, the resonance energy of the fluorophore and the LSPR should be carefully adjusted with an appropriate distance between the metal NPs and the emitter.