Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer

Patrick R. Brown, Richard R. Lunt, Ni Zhao, Timothy P. Osedach, Darcy D. Wanger, Liang Yi Chang, Moungi G. Bawendi, Vladimir Bulović

Research output: Research - peer-reviewArticle

  • 159 Citations

Abstract

The ability to engineer interfacial energy offsets in photovoltaic devices is one of the keys to their optimization. Here, we demonstrate that improvements in power conversion efficiency may be attained for ZnO/PbS heterojunction quantum dot photovoltaics through the incorporation of a MoO3 interlayer between the PbS colloidal quantum dot film and the top-contact anode. Through a combination of current-voltage characterization, circuit modeling, Mott-Schottky analysis, and external quantum efficiency measurements performed with bottom- and top-illumination, these enhancements are shown to stem from the elimination of a reverse-bias Schottky diode present at the PbS/anode interface. The incorporation of the high-work-function MoO3 layer pins the Fermi level of the top contact, effectively decoupling the device performance from the work function of the anode and resulting in a high open-circuit voltage (0.59 ± 0.01 V) for a range of different anode materials. Corresponding increases in short-circuit current and fill factor enable 1.5-fold, 2.3-fold, and 4.5-fold enhancements in photovoltaic device efficiency for gold, silver, and ITO anodes, respectively, and result in a power conversion efficiency of 3.5 ± 0.4% for a device employing a gold anode.

LanguageEnglish (US)
Pages2955-2961
Number of pages7
JournalNano Letters
Volume11
Issue number7
DOIs
StatePublished - Jul 13 2011
Externally publishedYes

Profile

Semiconductor quantum dots
Heterojunctions
Anodes
molybdenum trioxide
heterojunctions
anodes
quantum dots
Gold
Conversion efficiency
gold
augmentation
Open circuit voltage
Fermi level
Quantum efficiency
Silver
Interfacial energy
Short circuit currents
Diodes
Lighting
Engineers

Keywords

  • heterojunction
  • MoO
  • PbS
  • quantum dot
  • Schottky barrier
  • solar cell

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

Cite this

Brown, P. R., Lunt, R. R., Zhao, N., Osedach, T. P., Wanger, D. D., Chang, L. Y., ... Bulović, V. (2011). Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer. Nano Letters, 11(7), 2955-2961. DOI: 10.1021/nl201472u

Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer. / Brown, Patrick R.; Lunt, Richard R.; Zhao, Ni; Osedach, Timothy P.; Wanger, Darcy D.; Chang, Liang Yi; Bawendi, Moungi G.; Bulović, Vladimir.

In: Nano Letters, Vol. 11, No. 7, 13.07.2011, p. 2955-2961.

Research output: Research - peer-reviewArticle

Brown, PR, Lunt, RR, Zhao, N, Osedach, TP, Wanger, DD, Chang, LY, Bawendi, MG & Bulović, V 2011, 'Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer' Nano Letters, vol 11, no. 7, pp. 2955-2961. DOI: 10.1021/nl201472u
Brown PR, Lunt RR, Zhao N, Osedach TP, Wanger DD, Chang LY et al. Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer. Nano Letters. 2011 Jul 13;11(7):2955-2961. Available from, DOI: 10.1021/nl201472u
Brown, Patrick R. ; Lunt, Richard R. ; Zhao, Ni ; Osedach, Timothy P. ; Wanger, Darcy D. ; Chang, Liang Yi ; Bawendi, Moungi G. ; Bulović, Vladimir. / Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer. In: Nano Letters. 2011 ; Vol. 11, No. 7. pp. 2955-2961
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