Efficient electron injection in non-toxic silver sulfide (Ag2S) sensitized solar cells

Heping Shen, Xingjian Jiao, Dan Oron, Jianbao Li, Hong Lin

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

α-Ag2S, with a direct forbidden bandgap of about 1.0 eV, is a non-toxic low bandgap semiconductor which can readily be deposited in the form of a thin film by chemical bath deposition. In a solar cell configuration, it can potentially provide a high short-circuit current due to the infrared absorption, and is compatible with the polysulfide electrolyte. Its practical use in a solar cell depends, however, critically on band alignment between the Ag2S, the oxide anode and the electrolyte redox potential. Here we examine the conduction band (CB) offsets in the nanostructured α-Ag 2S sensitized TiO2 and SnO2 electrodes by X-ray Photoelectron Spectroscopy, and show that they can significantly differ from the extrapolated bulk values. The much higher CB offset for SnO 2/Ag2S interface (∼0.6 eV) compared with that of ∼0.2 eV for TiO2/Ag2S, supplied a sufficient injection driving force and was favorable for the electron separation at the heterojunction. When fabricated into solar cells, a dramatically higher current density under AM 1.5 illumination for the SnO2/Ag2S heterojunction was obtained, which was contributed by the efficient electron injection.

Original languageEnglish
Pages (from-to)8-13
Number of pages6
JournalJournal of Power Sources
Volume240
DOIs
Publication statusPublished - May 6 2013

Keywords

  • Conduction band offset
  • Electron injection
  • Non-toxic
  • Semiconductor sensitized solar cell
  • Silver sulfide

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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