Influence of doped Alq3 layer on performance of MEH-PPV, MDMO-PPV, and P3HT polymer light-emitting diodes

Abstract

The present study examined the influence of a doped Tris(8-hydroxyquinolinato) aluminium (Alq3). Layer on the performance of polymer-based organic light-emitting diodes (PLEDs) using Silvaco Atlas software. The luminance and recombination rate of a device depends on the physical properties of the active layer and of the effective layers on the active layer. Insertion of a doped Alq3 layer between the active layer and cathode increased the recombination rate of the middle layer that had been limited by the anode and cathode of the device. Better understanding the effect of the doped Alq3 layer on the parameters of mobility, lifetime, and band gap of the active layer and the performance of the device is necessary to achieve further improvement in these applications. This work presents a theoretical study of the influence of the Alq3 layer on PLEDs having different active layers. Poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV), poly(3-hexylthiophene) (P3HT), and poly[2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) organic layers were deposited onto an ITO substrate that was completed using calcium as a cathode with a work function of 2.9 eV. The Langiven model was used to analyze the recombination rate and luminance and indicated that the doped Alq3 layer between the active layer and cathode increased performance of the middle layer and improved the P3HT, MEH-PPV, and MDMO-PPV PLEDs. The MEH-PPV device showed the most improvement in comparison with the MDMO-PPV and P3HT devices. This originated from appropriate overlapping of the doped Alq3 layer and the MEH-PPV active layer.