Internal field and interfaces in organic and perovskite optoelectronic devices investigated via electroabsorption spectroscopy

Abstract

The performance of optoelectronic devices based on organic molecular and metal halide perovskite, which are normally sandwiched between different metal electrodes, is strongly determined by the internal field and electrode/active materials interfaces. In the last decades, electroabsorption (EA) spectroscopy has been demonstrated as a powerful and noninvasive tool to in-situ characterize the internal field and interfaces in completed operational devices. The information obtained from EA enables not only to study the fundamental device physics, but also to real-time monitor the dynamic processes of whole working devices under external multi-physical fields. This review firstly introduces the working principle of EA in detail, focusing on the cases of EA spectroscopy in the built-in potential of the devices and interfacial states. Then, the versatile applications of EA spectroscopy, such as the measurements of dipole moment and Rashba splitting, and the degradation mechanisms of individual functional layers, are further discussed. We believe that EA will become a highly powerful tool to investigate diverse optoelectronic devices, especially in the device performance and stability optimization.