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Author Neo, Darren C. J. ♦ Assender, Hazel E. ♦ Watt, Andrew A. R. ♦ Stranks, Samuel D. ♦ Eperon, Giles E. ♦ Snaith, Henry J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword NANOSCIENCE AND NANOTECHNOLOGY ♦ CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ CADMIUM SULFIDES ♦ EPITAXY ♦ HETEROJUNCTIONS ♦ ION EXCHANGE ♦ LEAD SULFIDES ♦ PASSIVATION ♦ PHOTOLUMINESCENCE ♦ QUANTUM DOTS ♦ SATURATION ♦ SOLAR CELLS ♦ SURFACES
Abstract Multi-band gap heterojunction solar cells fabricated from a blend of 1.2 eV and 1.4 eV PbS colloidal quantum dots (CQDs) show poor device performance due to non-radiative recombination. To overcome this, a CdS shell is epitaxially formed around the PbS core using cation exchange. From steady state and transient photoluminescence measurements, we understand the nature of charge transfer between these quantum dots. Photoluminescence decay lifetimes are much longer in the PbS/CdS core/shell blend compared to PbS only, explained by a reduction in non-radiative recombination resulting from CdS surface passivation. PbS/CdS heterojunction devices sustain a higher open-circuit voltage and lower reverse saturation current as compared to PbS-only devices, implying lower recombination rates. Further device performance enhancement is attained by modifying the composition profile of the CQD species in the absorbing layer resulting in a three dimensional quantum cascade structure.
ISSN 00036951
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-09-07
Publisher Place United States
Journal Applied Physics Letters
Volume Number 107
Issue Number 10


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