Nanoparticle Electroluminescence: Controlling Emission Color Through Forster Resonance Energy Transfer in Hybrid Particles

Electroluminescent (EL) polymers are attractive for developing all-organic light-emitting devices (OLEDs) due to the potential advantages that polymeric systems may offer in the large-scale manufacturing of electronics. Nonetheless, many of these EL pi-conjugated polymers are inherently insoluble in the solvents employed in the intended solution-basd manufacturing processes. One such polymer is poly(2,5-dioctyl-1,4- phenylenevinylene) (POPPV), where the inherent lack of solubility of POPPV in organic solvents has frustrated its widespread application in devices and no OLEDs have been presented that exploit its electroluminescence characteristics. In this effort, a unique strategy is presented for the preparation of hybrid nanoparticles composed of POPPV, a green emitter (lambda(em) = 505 nm) and poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO), a blue emitter (lambda(em)= 417 nm). The aqueous-based nanoparticle dispersion composed of these hybrid particles is stable to aggregate and can be employed in the construction of OLEDs. The color characteristics of the electroluminescence for the devices can be tuned by exploiting the Forster resonance energy transfer between the polymers within a particle, while suppressing energy transfer between the particles. These aqueous-based nanoparticle dispersions are amenable to being printed into devices through high-throughput manufacturing techniques, for example, roll-to-roll printing.