Colloidal Synthesis and Optical/(Opto)electochemical Investigation of Chemically Non-Toxic Tin (II) Sulfide Nanoparticles
Final Report Abstract
1. The experimental apparatus required to undertake the electrochemical and optoelectrochemical investigations of nanoparticulate materials at an electrode interface have been assembled, tested, calibrated and applied to a number of interesting semiconductor nanoparticle materials. 2. A methodology by which the surface of a range of different oxidic interfaces can be decorated with a high surface concentration of a range of different nanoparticle materials has been developed and reported to the community. 3. The electrochemical behaviour of submonolayers of nanoparticles at an inert optically transparent electrode interface has been investigated and it has been determined that many of the features observed in the voltammetry profiles of the nanoparticles can be directly related to the behaviour observed in the bulk material and not, as many reports claim, to electron injection and extraction from the conduction band and valance bands respectively of the nanoparticles. 4. The optoelectrochemical response of a range of sizes of CdSe nanoparticles have been investigated and a number of important observations made: a. the method of EMAS has proven itself to be very sensitive providing bleach signals with high signal to noise ratios even on submonolayer quantities of nanoparticulate materials. b. The existence of an bleaching effect induced under applied potential that occurs across the full visible spectral range and affects at least five electronic transitions has been observed. c. The absolute positions with respect to the vacuum level of all transitions, for both the bulk and a wide range of quantum confined nanomaterials has been determined. d. We have also determined that all transitions bleach only after the by electronic states within the conduction band have started to become occupied. By using the rate of change of the bleaching intensity with respect to the applied potential we have developed a means by which the absolute position of the conduction band edge can be determined and confirmed using the multiple bleach signals.
Publications
- A versatile approach for coating oxidic surfaces with a range of nanoparticulate materials. J. Mater. Chem. C 2013 1(7) 1515
Poppe J., Gabriel S., Liebscher L., Hickey S.G., Eychmüller A.
(See online at https://doi.org/10.1039/c2tc00863g) - Photoelectrochemical Investigations of Semiconductor Nanoparticles and their Application to Solar Cells. J. Phys. Chem. C. 2014 118(30) 17123
Poppe J., Hickey S. G., Eychmüller A.
(See online at https://doi.org/10.1021/jp5016092)
