A polystyrene bearing perylene diimide pendants with enhanced solid state emission for white hybrid light-emitting diodes

•A copolymer comprising a polystyrene backbone and perylene diimide pendants was synthesized.•The wide distance of the fluorophores along the chain leads to high solid state PL efficiency.•This red emitter is successfully used to generate white light in an organic/inorganic hybrid LED.

We report the preparation of a luminescent linear polystyrene decorated with randomly distributed pendants of perylene diimide, where the quenching processes due to aggregation states, typical of perylene diimides, are efficiently suppressed. Compared to a blend with the same polystyrene/dye ratio, the copolymer shows a nearly four-fold increase in quantum efficiency. Stable white emitting devices are straightforwardly prepared by the combination of this red emitting copolymer, a suitable organic green emitter, and an inorganic commercial blue light source. The selected organic dyes have appropriate photophysical characteristics for converting the blue source into a white light emission and exhibit good film forming properties even in the blend. The control of the film thickness of the blended organic dyes along with their relative concentration allows a fine tuning of the color emission. The optimized hybrid white LED displays white emission with chromaticity coordinates of x = 0.31, y = 0.34, a color rendering index of 83 and an efficiency of 28 lm/W.

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