Interface study of the intermediate connectors in tandem organic devices

Abstract

The intermediate connectors play crucial roles in the performance of tandem organic light‐emitting diodes (OLEDs) because they are required to facilitate charge carrier transport and to guarantee transparency for light transmission and deposition compatibility. Understanding the physical properties of the intermediate connector is not only fundamentally important but is also crucial to developing high‐efficiency organic devices with a tandem structure. In this study, several effective intermediate connectors in tandem OLEDs using a doped or non‐doped organic p‐n heterojunction were systematically investigated by studying their interfacial electronic structures and corresponding device characteristics. The working mechanisms of the intermediate connectors are discussed herein by referring to their relevant energy levels with respect to those of the neighboring organic layers. The factors affecting the operation of the intermediate connectors in tandem OLEDs, as demonstrated herein, provide guidance for the identification of new materials and device architectures for high‐performance devices.

Keywords:

• tandem OLED
• stacked structure
• intermediate connector
• p‐n heterojunction
• doping

Notes

Functional Nano & Soft Materials Laboratory (FUNSOM) & Jiangsu Key Laboratory for Carbon‐based Functional Materials and Devices, Soochow University, Suzhou 215123, China

Center of Superdiamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, China