Up-conversion injection in Rubrene/Perylene-diimide-heterostructure electroluminescent diodes

TL;DR

This paper introduces a novel low-voltage electroluminescent diode scheme using up-conversion injection in a heterostructure, challenging existing charge injection models and proposing an Auger-type mechanism.

Contribution

The authors demonstrate a new device architecture that achieves low-voltage electroluminescence and propose an innovative injection mechanism explaining this behavior.

Findings

Electroluminescence with a turn-on voltage close to the photovoltaic open circuit voltage.

Turn-on voltage is about half the band gap, unlike traditional models.

Proposed Auger-fountain injection mechanism explains the low-voltage operation.

Abstract

We implement and demonstrate a scheme that permits to drive electroluminescence with an extremely low turn-on voltage. The device behaves like compound semiconductors, in which the electroluminescence turn-on voltage is about the same as the open circuit voltage for the photovoltaic effect. However, the electroluminescence turn-on voltage is about half of the band gap of the emitting material, that cannot be explained using current models of charge injection in organic semiconductors. We hereby propose explanation through an Auger-type two-step injection mechanism (Auger-fountain).