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Ultrastable PbSe nanocrystal quantum dots via in situ formation of atomically thin halide adlayers on PbSe(100)

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Title: Ultrastable PbSe nanocrystal quantum dots via in situ formation of atomically thin halide adlayers on PbSe(100)

Author(s): Woo J.Y.; Jae-Hyeon Ko; Song J.H.; Kim K.; Choi H.; Yong-Hyun Kim; Lee D.C.; Jeong S.

Subject: Field effect transistors, ; Passivation, ; Semiconductor quantum dots, ; Ambient conditions, ; DFT calculation, ; In-situ formations, ; Lead selenide, ; Nanocrystal quantum dots, ; Optoelectronic applications, ; Optoelectronic characteristics, ; PbSe nanocrystals, ; Semiconducting lead compounds

Journal: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, v.136, no.25, pp.8883 - 8886

Abstract: The fast degradation of lead selenide (PbSe) nanocrystal quantum dots (NQDs) in ambient conditions impedes widespread deployment of the highly excitonic, thus versatile, colloidal NQDs. Here we report a simple in situ post-synthetic halide salt treatment that results in size-independent air stability of PbSe NQDs without significantly altering their optoelectronic characteristics. From TEM, NMR, and XPS results and DFT calculations, we propose that the unprecedented size-independent air stability of the PbSe NQDs can be attributed to the successful passivation of under-coordinated PbSe(100) facets with atomically thin PbX2 (X = Cl, Br, I) adlayers. Conductive films made of halide-treated ultrastable PbSe NQDs exhibit markedly improved air stability and behave as an n-type channel in a field-effect transistor. Our simple in situ wet-chemical passivation scheme will enable broader utilization of PbSe NQDs in ambient conditions in many optoelectronic applications. © 2014 American Chemical Society.