White multi-layered polymer light emitting diode through matrix assisted pulsed laser evaporation

Abstract

The development of alternative deposition techniques for conjugated polymeric compounds is an important step towards the fabrication of low cost multi-layered organic light emitting diodes suitable for display or lighting applications. In this work we show a white light-emitting polymeric hetero-structured diode consisting of three stacked blue, red and green light emitting polymers. In order to circumvent the issue of selecting orthogonal solvents in solution-deposition approaches, we combine spin-coating with a matrix-assisted pulsed laser evaporation technique, resulting in the realization of a polymeric multi-layered stack. By controlling the carriers and the energy transfer across the three light emitting layer interfaces, as well as the interplay between the deposition parameters, a pure white colour emission with Commission Internationale de l'Éclairage coordinates of (X = 0.327, Y = 0.374) and a Color Rendering Index of 70 has been achieved. Our study represents the first proof of a light emitting diode made with multi-layer polymeric thin films emitting white light.