Role of PbSe structural stabilization in photovoltaic cells

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • D. Asil - , University of Cambridge (Author)
  • B. J. Walker - , University of Cambridge (Author)
  • B. Ehrler - , University of Cambridge (Author)
  • Y. Vaynzof - , University of Cambridge (Author)
  • A. Sepe - , University of Cambridge, Heidelberg University  (Author)
  • S. Bayliss - , University of Cambridge (Author)
  • A. Sadhanala - , University of Cambridge (Author)
  • P. C.Y. Chow - , University of Cambridge (Author)
  • P. E. Hopkinson - , University of Cambridge (Author)
  • U. Steiner - , University of Cambridge, Heidelberg University  (Author)
  • N. C. Greenham - , University of Cambridge (Author)
  • R. H. Friend - , University of Cambridge (Author)

Abstract

Semiconductor nanocrystals are promising materials for printed optoelectronic devices, but their high surface areas are susceptible to forming defects that hinder charge carrier transport. Furthermore, correlation of chalcogenide nanocrystal (NC) material properties with solar cell operation is not straight-forward due to the disorder often induced into NC films during processing. Here, an improvement in long-range ordering of PbSe NCs symmetry that results from halide surface passivation is described, and the effects on chemical, optical, and photovoltaic device properties are investigated. Notably, this passivation method leads to a nanometer-scale rearrangement of PbSe NCs during ligand exchange, improving the long-range ordering of nanocrystal symmetry entirely with inorganic surface chemistry. Solar cells constructed with a variety of architectures show varying improvement and suggest that triplet formation and ionization, rather than carrier transport, is the limiting factor in singlet fission solar cells. Compared to existing protocols, our synthesis leads to PbSe nanocrystals with surface-bound chloride ions, reduced sub-bandgap absorption and robust materials and devices that retain performance characteristics many hours longer than their unpassivated counterparts.

Details

Original languageEnglish
Pages (from-to)928-935
Number of pages8
JournalAdvanced functional materials
Volume25
Issue number6
Publication statusPublished - 11 Feb 2015
Peer-reviewedYes
Externally publishedYes