Importance of QD Purification Procedure on Surface Adsorbance of QDs and Performance of QD Sensitized Photoanodes

Quantum dots (QDs) have been utilized as light harvesting assemblies on photoanodes for applications in quantum dot sensitized solar cells. QDs are bound (sensitized) to a titanium dioxide surface using the bifunctional linker molecule 3-mercaptopropionic acid. The cadmium selenide QDs are synthesiz...

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Bibliographic Details
Published inJournal of physical chemistry. C Vol. 116; no. 5; pp. 3349 - 3355
Main Authors King, Laurie A, Riley, D. Jason
Format Journal Article
LanguageEnglish
Published Columbus, OH American Chemical Society 09.02.2012
Subjects
Applied sciences
C: Nanops and Nanostructures
Cross-disciplinary physics: materials science; rheology
Electronics
Energy
Exact sciences and technology
Materials science
Molecular electronics, nanoelectronics
Nanocrystalline materials
Nanoscale materials and structures: fabrication and characterization
Natural energy
Photovoltaic conversion
Physics
Quantum dots
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Solar cells. Photoelectrochemical cells
Solar energy
Solar cells
Purification
Quantum dots
Photocurrents
Cadmium selenides
Precipitation
Imaging
Morphology
Titanium
Ligands
Photoconductivity
Nanostructured materials
TOPO
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Summary:Quantum dots (QDs) have been utilized as light harvesting assemblies on photoanodes for applications in quantum dot sensitized solar cells. QDs are bound (sensitized) to a titanium dioxide surface using the bifunctional linker molecule 3-mercaptopropionic acid. The cadmium selenide QDs are synthesized following a trioctylphosphine oxide (TOPO) stabilized hot injection method. Prior to sensitization, QDs are subject to a common purification; cycles of alternate precipitation/redispersion in a nonsolvent/solvent. Through a systematic study, the critical role of this purification has been determined. With enhanced purification, the surface bound QD concentration has been shown to increase 5-fold. Imaging reveals that the QD agglomerates decrease in size and increase in population. Photocurrent measurements demonstrate the importance of the morphology and QD population on the ability of QD photoinjection and thus the necessity to control QD purification. These findings are discussed in light of recent literature on QD surface bound ligands.
ISSN:1932-7447
1932-7455
DOI:10.1021/jp210290j