Watching excitons move

Organic electronics is an emerging field of science and technology that represents a promising alternative to conventional electronics. Organic electronic devices are based on organic semiconductors, which combine attractive properties of organic materials with semiconducting behavior. The elementary excitation in these materials is a so-called “exciton” – a strongly bound pair of negative (electron) and positive (hole) charges. As a result, organic electronics essentially rely on exciton dynamics that have to be controlled and observed to ensure the development of high-efficient organic devices.

The Optical Condensed Matter Physics group (the Zernike Institute for Advanced Materials), together with colleagues from Princeton University (USA) and IMEC (Belgium), have recently made a step towards “watching” exciton dynamics in real-time within organic semiconductors. By utilizing a combination of state-of-the-art technological developments in thin film deposition, X-ray characterization, ultrafast spectroscopy, and computer modeling they developed a spectroscopic method to track the exciton dynamics in real time with unprecedented femtosecond accuracy. With this novel technique they demonstrated unusually efficient exciton diffusion in vacuum-deposited C70 fullerene layers, which is 10 times faster than in typical organic materials. The novel technique is deemed to pave the way to further development of efficient optoelectronic devices such as organic thin-film transistors, light-emitting transistors and lasers.

The results of this work are published in Physical Review Letters (O. V. Kozlov, F. de Haan, R. Kerner, B. P. Rand, D. Cheyns and M. S. Pshenichnikov, “Real-time tracking of singlet exciton diffusion in organic semiconductors”, Phys. Rev. Lett. 116, 057402, 2016

DOI:http://dx.doi.org/10.1103/PhysRevLett.116.057402