Light-emitting electrochemical cell
A light-emitting electrochemical cell (LEC or LEEC) is a solid-state device that generates light from an electric current (electroluminescence). LEC's are usually composed of two metal electrodes connected by (e.g. sandwiching) an organic semiconductor containing mobile ions. Aside from the mobile ions, their structure is very similar to that of an organic light-emitting diode (OLED).
LECs have most of the advantages of OLEDs, as well as additional ones:
- The device does not depend on the difference in work function of the electrodes. Consequently, the electrodes can be made of the same material (e.g., gold). Similarly, the device can still be operated at low voltages.
- The thickness of the active electroluminescent layer is not critical for the device to operate. This means that:
While electroluminescence had been seen previously in similar devices, the invention of the polymer LEC is attributed to Pei et al. Since then, numerous research groups, and even a few companies, have worked on improving and commercializing the devices.
In March 2012, Tricia Breen Carmichael et al. of the University of Windsor reported the first inherently stretchable LEEC using an elastomeric emissive material (at room temperature). It was featured on the cover of the May 22, 2012 edition of the journal Advanced Materials. Dispersing an ionic transition metal complex into an elastomeric matrix enables the fabrication of intrinsically stretchable light-emitting devices that possess large emission areas (∼175 mm2) and tolerate linear strains up to 27% and repetitive cycles of 15% strain. This work demonstrates the suitability of this approach to new applications in conformable lighting that require uniform, diffuse light emission over large areas.
In 2012, Ludvig Edman and Andreas Sandström of the Umeå University reported that they succeeded in making organic light-emitting electrochemical cells (LECs) using a roll-to-roll compatible process under ambient conditions.
- Electrochemical cell
- Light-emitting diode
- Organic light-emitting diode
- Gao, J.; Dane, J. (2003), Planar polymer light-emitting electrochemical cells with extremely large interelectrode spacing, "Applied Physics Letters", Applied Physics Letters 83 (15): 3027, doi:10.1063/1.1618948
- Shin, J.-H.; Dzwilewski, A.; Iwasiewicz, A.; Xial, S.; Fransson, A.; Ankah, G.N.; Edman, L. (2006), Light emission at 5 V from a polymer device with a millimeter-sized interelectrode gap, "Applied Physics Letters", Applied Physics Letters 89: 013509, doi:10.1063/1.2219122
- Matyba, P.; Yamaguchi, H.; Eda, G.; Chhowalla, M.; Edman, L.; Robinson, N.D. (2010), Graphene and Mobile Ions: The Key to All-Plastic, Solution-Processed Light-Emitting Devices, "ACS Nano", ACS Nano 4 (2): 637–642, doi:10.1021/nn9018569, PMID 20131906
- Yu, Z.; Hu, L.; Liu, Z.; Sun, M.; Wang, M.; Grüner, G.; Pei, Q. (2009), Fully bendable polymer light emitting devices with carbon nanotubes as cathode and anode, "Applied Physics Letters", Applied Physics Letters 95 (20): 203304, doi:10.1063/1.3266869
- Mauthner, G.; Landfester, K.; Kock, A.; Bruckl, H.; Kast, M.; Stepper, C.; List, E.J.W. (2008), Inkjet printed surface cell light-emitting devices from a water-based polymer dispersion, "Organic Electronics", Organic Electronics 9 (2): 164, doi:10.1016/j.orgel.2007.10.007
- Gao, J.; Dane, J. (2004), Visualization of electrochemical doping and light-emitting junction formation in conjugated polymer films, "Applied Physics Letters", Applied Physics Letters 84 (15): 2778, doi:10.1063/1.1702126
- Pei, Q.B.; Yu, G.; Zhang, C.; Yang, Y.; Heeger, A.J. (1995), Polymer Light-Emitting Electrochemical-Cells, "Science", Science 269 (5227): 1086, doi:10.1126/science.269.5227.1086, PMID 17755530
- Heather L. Filiatrault , Gyllian C. Porteous , R. Stephen Carmichael , Gregory J. E. Davidson , and Tricia Breen Carmichael* DOI: 10.1002/adma.20120448
- Organic LEC's made using a roll-to-roll process under ambient conditions
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