Control of photoluminescence emission from a conjugated polymer using an optimised microactivity structure

It is shown that by careful control of the position of a thin emissive polymer layer poly(p-phenylene vinylene) [PPV] within a microactivity structure, it is possible to strongly influence the forward photoluminescence (PL) emission intensity. In one structure, the PPV layer was placed at a confined photon-field antinode where the coupling strength between the emitting dipoles and the field is expected to be a maximum. This resulted in an enhancement of the PL emitted into the forward direction. Placing the PPV layer at a photon-field node resulted in strong suppression of PL. The ratio of the forward emission intensity between these two extreme cases was 55 ± 25. The measured emission intensities are compared to predictions from a transfer matrix model and are shown to be in very reasonable agreement.