The electrochemical stability of organic materials and their influence on the operational stability of organic light-emitting devices

Abstract

Organic light-emitting diodes (OLEDs) have drawn great attention because of their potential application in full-color displays and solid-state lighting. The efficiency of OLEDs has been significantly boosted over the last two decades; however, the device stability is still a challenge. As the charge-carrier transport in OLEDs is generally considered as a chain of redox processes between the neutral molecules and the corresponding radical ions, the electrochemical property of the materials should be an important factor associated with the operational stability of OLEDs. In this perspective, we reviewed the recent advances on the electrochemical property of OLEDs materials, focusing on revealing the correlation between the electrochemical properties of OLEDs materials and the operational stability of the corresponding devices. We try to summarize as follows: (1) The electrochemical instability of unipolar materials has been recognized as one of the intrinsic factors leading to the device degradation; (2) The high electrochemical stability of bipolar materials has proved to be conducive to significantly enhance the stability of the corresponding devices, but not guarantee the devices definitely with high stability; (3) The influence of the molecular stability on device stability, and the intrinsic degradations mechanism of OLEDs still remain to be further explored. It is expected that the in-depth knowledge of the materials stability and the degradation mechanisms of OLEDs can help to improve the stability of other organic optoelectronic materials and devices, thus promoting the development of organic electronics and related industries.