Long lived photo- and electroluminescence from a side-chain polymer porphyrin blend

We utilised the technique of combining electroluminescent polymers with pho to-emissive molecular dopants to create a blend that has an absorption spec trum and electrical transport properties dominated by the polymer, but phot oluminescence and electroluminescence spectra dominated by the dopant. The dopant molecule, platinum octaethyl porphyrin, is well known as a solid sta te phosphor [1], and we have succeeded in creating a system with a luminesc ence lifetime of the order of tens of microseconds. In addition, although s ome photoluminescence quantum efficiency is inevitably lost in the energy t ransfer process, the blended system is still found to be 29% efficient. Whe n the polymer-dopant blend is used to make light-emitting diodes (LEDs) whi ch are tested in pulsed mode, the light emission from the device is seen to decay after the voltage pulse with the same lifetime as the photoluminesce nce. The long-lived emission is a strong indication that the blend emits fr om the triplet manifold of the dopant molecule.