Ambipolar light-emitting field-effect transistors based on molecular thin films

Organic light-emitting field-effect transistors are a new class of electrooptical devices that could provide a novel architecture to address open questions concerning fundamental optoelectronic phenomena in organic semiconductors, and can be potentially used as key components in optical communication systems, advanced display technology, solid-state lighting and organic lasers. The realisation of Organic Light-Emitting Transistors (OLETs) with high quantum efficiency and fast switching time is crucial for the development of highly integrated organic optoelectronic systems. Organic molecular materials having intrinsically ambipolar transport and high charge mobility values are restricted in number and show poor light-emission efficiency. Here, we describe the device operation principles of OLETs and report on the approach of combining p-type and n-type molecular materials in a layered structure to achieve ambipolar transport and light emission. Imaging of the individual layers and a correlation between active layer structure and device electrical performances is achieved by means of the Laser Scanning Confocal Microscopy.