Ultrafast electron injection from adsorbates to semiconductor nanoparticles

Xin Ai, Neil A. Anderson, John B. Asbury, Encai Hao, Tianquan Lian

Research output: Contribution to journalConference articlepeer-review

4 Scopus citations


Electron transfer (ET) dynamics between molecular adsorbates and semiconductor nanoparticles has been a subject of intense recent interest because of relevance to many applications of nanomaterials, such as dye-sensitized solar cells, molecular electronics and sensors. However, it is still unclear how the charge transfer rate depends on the properties of molecules and semiconductors. In this paper we examine electron injection from Ru and Re polypyridyl complexes to metal oxide (TiO 2) SnO 2 and ZnO) nanocrystalline thin films. Adsorbates with different energetics and electronic coupling are compared to identify molecular properties that influence ET dynamics. Different semiconductor nanomaterials are compared to understand the dependence on conduction band composition and energetics. ET dynamics were found to be biphasic consisting of ultrafast (<100fs) and slower components, with varying partitioning between them and rates of slow components. These kinetics can be well described by a two-state injection model, which includes injection from both unthermalized and thermalized excited states and competition between electron injection and intramolecular relaxation from the unthermalized state. The dependence of ET rates on various molecular and semiconductor properties is also discussed.

Original languageEnglish (US)
Pages (from-to)147-158
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2003
EventPhysical Chemistry of Interfaces and Nanomaterials II - San Diego, CA, United States
Duration: Aug 6 2003Aug 8 2003

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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