High pressure research of conjugated molecules

Blue emitting organic semiconductors under high pressure: status and outlook

This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors.


Reports on Progress in Physics, Volume 79, Number 6

Organic conjugated polymers are of great interest for electronic applications such as LEDs, flat screen and polymer solar cells, because they are inexpensive, easy to produce and flexible in shape. However the opto-electronic properties of these polymers greatly depend on their molecular structure. Therefore it is important to develop reliable experimental procedures to investigate structural changes in these polymers.

With the University of Missouri, University of Wuppertal and European synchrotrons, PETRA III and MAX IV Laboratory, DTU Physics is working on compressed polyfluorenes and related materials. This research line uses pressure as a tool to control structure and molecular interactions and therefore optical emission and transport properties without chemical intervention. Interesting aspects of this work have been recently highlighted by Matti Knaapila and Suchi Guha in Reports on Progress in Physics..

The figure at the top of this page shows an image of compressed polyfluorene at 310 kbar pressure including a map of a specific X-ray diffraction peak. The position of this peak describes the torsion angle between fluorene repeats and the map provides information of polymer conformation across the sample.

See video abstract of review article


Matti Knaapila
DTU Physics
+45 93 51 13 40