Highly Efficient Electroluminescence From Hybrid Silicon Nanocrystal-Organic Light-Emitting Devices

Tuesday, October 18, 2011: 3:15 PM
M100 G (Minneapolis Convention Center)
Kai-Yuan Cheng1, Rebecca Anthony2, Uwe R. Kortshagen2 and Russell J. Holmes1, (1)Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, (2)Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN

Colloidal semiconductor nanocrystals (NCs) have received considerable attention for optoelectronic applications due to their high photoluminescence efficiency and broad spectral tunability. Semiconductor NCs can be solution processed permitting integration into hybrid light-emitting devices that use organic semiconductors as charge transport layers. While electroluminescence (EL) from group II-VI and III-V NCs has been well studied, emission from group IV NCs including silicon (Si) has not been characterized as extensively. Here, we demonstrate efficient EL from hybrid nanocrystal-organic light-emitting devices (NC-OLEDs) containing SiNCs passivated with ligands of 1-dodecene. In such hybrid NC-OLEDs, a forward-emitted external quantum efficiency of 8.6% at a wavelength of 853 nm is obtained for devices containing 5-nm SiNCs with emission originating solely from the SiNCs. Comparable high efficiency is also obtained for SiNCs emitting at a wavelength of 777 nm. The high device efficiency is noted to be very robust and can be observed with electron transport materials whose mobility varies across three orders of magnitude. In this study, the relative roles of electron mobility and charge/exciton confinement will be discussed in the content of realizing high efficiency.

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