Tuning the performance of layer-by-layer assembled organic light emitting diodes by controlling the position of isolating clay barrier sheets

We have fabricated organic light emitting diodes (OLEDs) based on poly(p-phenylenevinylene) (PPV) and poly(methacrylic acid) (PMA), including an isolating layer composed of montmorillonite. We show that the single clay layer influences the behavior of the devices, lowering current densities and increasing light output in comparison with pure polymer systems. The subnanometer positioning of this isolating barrier within the active medium with respect to both electrodes, which is easily controlled by the deposition sequence, plays a key role for the electrooptical properties of the diodes.