Colloidal CdSe1-xSx Nanoplatelets with Narrow and Continuously-Tunable Electroluminescence

Colloidal nanoplatelets, quasi-two-dimensional quantum wells, have recently been introduced as colloidal semiconductor materials with the narrowest known photoluminescence line width (∼10 nm). Unfortunately, these materials have not been shown to have continuously tunable emission but rather emit at discrete wavelengths that depend strictly on atomic-layer thickness. Herein, we report a new synthesis approach that overcomes this issue: by alloying CdSe colloidal nanoplatelets with CdS, we finely tune the emission spectrum while still leveraging atomic-scale thickness control. We proceed to demonstrate light-emitting diodes with sub-bandgap turn-on voltages (2.1 V for a device emitting at 2.4 eV) and the narrowest electroluminescence spectrum (FWHM ∼12.5 nm) reported for colloidal semiconductor LEDs.

Fan, F., Kanjanaboos, P., Saravanapavanantham, M., Beauregard, E., Ingram, G., Yassitepe, E., … Sargent, E. H. (2015). Colloidal CdSe1–xSxNanoplatelets with Narrow and Continuously-Tunable Electroluminescence. Nano Letters, 15(7), 4611–4615. doi:10.1021/acs.nanolett.5b01233

This publication is based in part on work supported by Award KUS-11-009-21, made by King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program, and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. E.Y. acknowledges support from FAPESP-BEPE (2014/18327-9) fellowship. The authors thank S. Hoogland, D. Se llan, X. Lan, Z. Yang, and L. Quasi for useful discussions. The authors thank L. Levina, E. Palmiano, R. Wolowiec, and D. Kopilovic for their technical help over the course of this study. We thank the Centre for Microfluidic Systems in Chemistry and Biology (Toronto, Ontario) for access to the atomic force microscope.




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