Polaron Pair-Mediated\nRadiative Recombination of Singlet\nExcitons in a Conjugated Polymer Aggregate by Plasmonic and Semiconductor\nNanocrystals

We\ninvestigated the excited-state dynamics of a conjugated polymer\n(CP:P3HT)-based ternary hybrid system containing P3HT-coated gold\nnanoparticles and quantum dots. Transient absorption spectroscopy\nresults revealed that polaron pairs (PPs) originating from nonrelaxed\nsinglet (S<sub>1</sub>) excitons of the CP aggregate in the ternary\nsystem have shorter electron–hole separation distances than\nthose of PPs in the neat CP aggregate because of the photophysical\neffects of plasmonic and semiconductor nanocrystals. In particular,\nthe shorter electron–hole distances of PPs led to more back-recombination\nto S<sub>1</sub> excitons than dissociation into positive polarons\nin the ternary system, resulting in increased S<sub>1</sub> radiative\nrecombination compared with that in the neat CP system. Thus, the\nphotoluminescence intensity of the CP aggregate in the ternary system\nincreased. Our findings provide new insights into the excited-state\ndynamics of CPs and pave the way for the development of next-generation\nhigh-efficiency optoelectronic devices.