Organic semiconductor heterojunctions: electrode-independent charge injectors for high-performance organic light-emitting diodes

摘要

The use of organic semiconductor heterojunctions has enabled electrode-independent charge injection in organic light-emitting diodes (OLEDs). Conventionally, metals with high and low work functions are respectively used to achieve effective injection of electrons and holes in OLEDs. Now, Yonghua Chen and co-workers in China, the USA and Singapore have used a C60/pentacene semiconductor heterojunction to realize highly efficient OLEDs in which charge injection is independent of the electrode work function. The OLEDs exhibited enhanced efficiency and stability over conventional OLEDs. This high performance was maintained even when the low work function aluminium electrode was replaced with high work function electrodes made from gold, silver and copper – metals that are chemically unreactive and stable in air. The researchers anticipate that this new design concept will greatly extend the range of electrodes that can be used in OLEDs.