Hybrid Organic-Inorganic Light-Emitting Diodes

• Published in: Advanced materials (Weinheim) 2011-04, Vol.23 (16), p.1829-1845
• Main Authors: Sessolo, Michele, Bolink, Henk J.
• Format: Article
• Language: English
• Subjects: Luminescent Agents - chemistry; Metals - chemistry; Organic Light-Emitting Diodes; Oxides - chemistry; Polymeric Materials; Polymers - chemistry; Quantum Theory; Semiconductors; Thin Films; Titanium Dioxide; Zinc Oxide
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201004324

The demonstration of colour tunability and high efficiency has brought organic light‐emitting diodes (OLEDs) into the displays and lighting market. However, high production costs due to expensive deposition techniques and the use of reactive materials still limit their market entry, highlighting the need for novel concepts. This has driven the research towards the integration of both organic and inorganic materials into devices that benefit from their respective peculiar properties. The most representative example of this tendency is the application of metal oxides in organic optoelectronics. Metal oxides combine properties such as high transparency, good electrical conductivities, tuneable morphology, and the possibility of deposition on large areas with low‐cost techniques. The use of metal oxides as charge injection interfaces in OLEDs has also been investigated. Hybrid organic–inorganic light‐emitting diodes (HyLEDs) are inverted OLEDs that employ air‐stable metal oxides as the charge injection contacts. They are emerging as a potential competitor to standard OLEDs, thanks to their intrinsic air stable electrodes and solution processability, which could result in low‐cost, large area, light‐emitting devices. This article reviews the short history of this class of devices from its first solid state example published in 2006 to the present achievements. The data presented shed light on the electronic mechanism behind the functioning of HyLEDs and give guidelines for their further optimization. Hybrid organic–inorganic light‐emitting diodes (HyLEDs) employ solution‐processable and air‐stable metal oxides as charge injecting contacts. In this article, the recent achievements in understanding and performance are reviewed, demonstrating the potential of HyLEDs for future lighting and displays applications.