Charge injection and electrical properties of GaN and ZnO / organic semiconductor heterosystems
Charge transfer across organic layer/inorganic electrode interfaces strongly determines the efficiency of organic electronic devices, such as organic light-emitting diodes, field-effect transistors or organic solar cells. Yet, despite the rapid commercialization of hybrid organic/inorganic electronics for applications such as AMOLED (active matrix organic light emitting diode) displays for mobile phones, little is understood about the fundamental principles of charge injection across these interfaces. One of the reasons for this lack of understanding is the difficulty in performing well controlled experiments.
This project focuses on the performance of well-defined experiments. Starting from well-characterized electrodes with the ability to grow atomically flat surfaces, the morphological as well as the energetic structure of the deposited molecular layers will be controlled carefully.
Through the course of the project, we aim to:
- determine how energy level alignment affects charge injection,
- develop ways to control and measure disorder in HIOS structures with high reproducibility,
- determine how energetic disorder influences charge injection and transport,
- examine the differences between devices prepared under "clean" and "realistic" conditions,
- find ways to modify the inorganic/organic interfaces to facilitate electron injection,
- develop one-dimensional and three-dimensional empirical models of injection-limited currents for smooth and rough interfaces with amorphous OSCs,
- produce a set of rules for achieving good electron injection into OSCs.