Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 54: Joint Session: Organic Semiconductors IV: Excitations and Charges
HL 54.2: Talk
Wednesday, March 16, 2011, 14:30–14:45, ZEU 222
Light-Emitting Organic Memory — •Peter O. Körner, R. Clayton Shallcross, Vincent Aubert, Eduard Maibach, Philipp Zacharias, and Klaus Meerholz — Department of Chemistry, University of Cologne
We report on light-emitting organic memory (LE-OMEM) devices composed of multiple solution-processed layers. The active layer of our LE-OMEM devices is comprised of crosslinkable dithienylethene photochromes (XDTE) that can be optically switched between two energetically distinct and thermally stable isomers. Exploiting the difference in the HOMO and LUMO levels of these two isomers we use such a layer as an electrical switch within our OLED layer stack. We demonstrate that the ON/OFF ratio in current (OORj) as well as in electroluminescence (OORL) of such devices is exponentially dependent on the difference in the largest charge injection barrier between the ON and OFF state of the device. Optimized devices displayed impressive fatigue resistance and afforded values for OORj and OORL of greater than 103. We focus on a variety of crosslinkable DTE molecules of varying structure and functionality with an emphasis on OOR, device stability over multiple read/write/erase cycles (fatigue resistance) and switching rates. Current induced switching allows for electrical writing and reading of grey level information in these XDTE devices. We studied this electrical switching behavior to gain further insight into the distinct switching mechanisms within the XDTE layer. These fundamental studies are a first step towards a completely electrically driven LE-OMEM.