Effects of Lattice Strain and Band Offset on Electron Transfer Rates in Type-II Nanorod Heterostructures

J Phys Chem Lett. 2012 May 3;3(9):1094-8. doi: 10.1021/jz300275f. Epub 2012 Apr 12.

Abstract

Type-II nanorod heterostructures (NRHs) exhibit efficient directional charge separation and provide the potential to control this flow of charges through changes in structure and composition. We use transient-absorption spectroscopy to investigate how the magnitude of band offset and lattice strain alters dynamics of photogenerated electrons in CdSe/CdTe type-II NRHs. In the absence of alloying and strain effects, electron transfer occurs in ∼300 fs. Reducing the conduction band offset by means of alloying leads to an even shorter charge-separation time (<200 fs), whereas curved NRHs with pronounced strain exhibit a longer charge-separation time of ∼700 fs.