Trap-Induced Dispersive Transport and Dielectric Loss in PbS Nanoparticle Films

Alina Chanaewa*, Katharina Poulsen, Alexander Gräfe, Christoph Gimmler, Elizabeth Von Hauff

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

In this work, we investigate the electrical and dielectric response of lead sulfide (PbS) nanoparticle (NP) films with impedance spectroscopy. In particular, the influence of the ligand passivation on the surface trap state density of PbS NPs is demonstrated by comparing two different types of ligands: ethane-1,2-dithiol (EDT) and 3-sulfanylpropanoic acid (MPA). We observe that the MPA treatment passivates the PbS surface more efficiently than EDT. By analyzing the dielectric loss spectra, we are able to visualize shallow trap states in the bulk of PbS-EDT films and correlate this with the dispersive response observed in the impedance spectra. Evidence of deep trap states is revealed for both PbS-EDT and PbS-MPA diodes. Under illumination, the PbS-MPA and PbS-EDT films demonstrate almost identical trap profiles, showing solely the deep trap state densities. We conclude that the deep traps are related to the stoichiometry of the PbS NPs.

Original languageEnglish
Pages (from-to)121-134
Number of pages14
JournalZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS
Volume231
Issue number1
DOIs
Publication statusPublished - 1 Jan 2017

Keywords

  • dielectric analysis
  • impedance spectroscopy
  • PbS nanoparticle films
  • transport
  • trap states

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