High-performance quantum dot-sensitized solar cells based on sensitization with CuInS 2 quantum dots/CdS heterostructure

Tzung Luen Li, Yuh Lang Lee, Hsisheng Teng

Research output: Contribution to journalArticlepeer-review

276 Citations (Scopus)

Abstract

A high-performance quantum dot-sensitized solar cell (QDSSC) is reported, which consists of a TiO 2/CuInS 2-QDs/CdS/ZnS photoanode, a polysulfide electrolyte, and a CuS counter electrode. The sensitization process involves attaching presynthesized CuInS 2 QDs (3.5 nm) to a TiO 2 substrate with a bifunctional linker, followed by coating CdS with successive ionic layer adsorption and reaction (SILAR) and ZnS as the last SILAR layer for passivation. This process constructs a sensitizing layer that comprises CdS nanocrystals, closely packed around the earlier-linked CuInS 2 QDs, which serve as the pillars of the layer. The CuS counter electrode, prepared via successive ionic solution coating and reaction, has a small charge transfer resistance in the polysulfide electrolyte. The QDSSC exhibits a short-circuit photocurrent (J sc) of 16.9 mA cm -2, an open-circuit photovoltage (V oc) of 0.56 V, a fill factor of 0.45, and a conversion efficiency of 4.2% under one-sun illumination. The heterojunction between the CuInS 2 QDs and CdS extends both the optical absorption and incident photon conversion efficiency (IPCE) spectra of the cell to a longer wavelength of approximately 800 nm, and provides an IPCE of nearly 80% at 510 nm. The high TiO 2 surface coverage of the sensitizers suppresses recombination of the photogenerated electrons. This results in a longer lifetime for the electrons, and therefore, the high V oc value. The notably high J sc and V oc values demonstrate that this sensitization strategy, which exploits the quantum confinement reduction and other synergistic effects of the CuInS 2-QDs/CdS/ZnS heterostructure, can potentially outperform those of other QDSSCs.

Original languageEnglish
Pages (from-to)5315-5324
Number of pages10
JournalEnergy and Environmental Science
Volume5
Issue number1
DOIs
Publication statusPublished - 2012 Jan 1

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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