Low-temperature approach to high-yield and reproducible syntheses of high-quality small-sized PbSe colloidal nanocrystals for photovoltaic applications

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DOIResolve DOI: http://doi.org/10.1021/am101129m
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TypeArticle
Journal titleACS Applied Materials and Interfaces
Volume3
Issue2
Pages553565; # of pages: 13
Subjectformation mechanism; monomer; nucleation/growth; reducing agent; small-sized PbSe nanocrystals; quantum dots; high particle/reaction yield; photovoltaics
AbstractSmall-sized PbSe nanocrystals (NCs) were syn-thesized at low temperature such as 50−80 °C with high reaction yield (up to 100%), high quality, and high synthetic reproducibility, via a noninjection-based one-pot approach. These small-sized PbSe NCs with their first excitonic absorption in wavelength shorter than 1200 nm (corresponding to size < 3.7 nm) were developed for photovoltaic applications requiring a large quantity of materials. These colloidal PbSe NCs, also called quantum dots, are high-quality, in terms of narrow size distribution with a typical standard deviation of 7−9%, excellent optical properties with high quantum yield of 50−90% and small full width at half-maximum of 130−150 nm of their band-gap photoemission peaks, and high storage stability. Our synthetic design aimed at promotion of the formation of PbSe monomers for fast and sizable nucleation with the presence of a large number of nuclei at low temperature. For formation of the PbSe monomer, our low-temperature approach suggests the existence of two pathways of Pb−Se (route a) and Pb−P (route b) complexes. Either pathway may dominate, depending on the method used and its experimental conditions. Experimentally, a reducing/nucleation agent, diphenylphosphine, was added to enhance route b. The present study addresses two challenging issues in the NC community, the monomer formation mechanism and the reproducible syntheses of small-sized NCs with high yield and high quality and large-scale capability, bringing insight to the fundamental understanding of optimization of the NC yield and quality via control of the precursor complex reactivity and thus nucleation/growth. Such advances in colloidal science should, in turn, promote the development of next-generation low-cost and high-efficiency solar cells. Schottky-type solar cells using our PbSe NCs as the active material have achieved the highest power conversion efficiency of 2.82%, in comparison with the same type of solar cells using other PbSe NCs, under Air Mass 1.5 global (AM 1.5G) irradiation of 100 mW/cm2.
Publication date
LanguageEnglish
AffiliationNRC Steacie Institute for Molecular Sciences; NRC Institute for Microstructural Sciences; NRC Institute for Chemical Process and Environmental Technology; National Research Council Canada
Peer reviewedYes
NPARC number19739617
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Record identifiereebe23e6-b99d-43ed-9cfe-5d7910c2e273
Record created2012-04-02
Record modified2016-05-09
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