Ultralong-range exciton transport in submillimeter-scale spherulite film of π-conjugated polymers

The performance of π-conjugated polymer films is often constrained by short exciton diffusion lengths resulting from local defects and variations in interchain packing. In this study, the authors report the formation of large-area, submillimeter-scale spherulites by subjecting a spin-coated polydiarylfluorene film to solvent vapor annealing. These spherulitic structures enable ultralong-range exciton transport across submillimeter scales. Moreover, polymer light-emitting diodes (PLEDs) fabricated from these large-area spherulite films exhibit stable and efficient deep-blue electroluminescence.