Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-07-07T20:17:33.334Z Has data issue: false hasContentIssue false

Photoluminescence Properties of Core/Shell CdSe/ZnS Quantum Dots Encapsulated with Transparent layers for Third Generation Photovoltaics

Published online by Cambridge University Press:  16 August 2011

Bahareh Sadeghimakki
Affiliation:
Center for Advanced Photovoltaic Devices and Systems (CAPDS), Waterloo, ON N2L3G1 Canada Electrical and Computer Engineering Department, University of Waterloo, Waterloo, ON N2L3G1 Canada
Navid Mohammad Sadeghi Jahed
Affiliation:
Center for Advanced Photovoltaic Devices and Systems (CAPDS), Waterloo, ON N2L3G1 Canada Electrical and Computer Engineering Department, University of Waterloo, Waterloo, ON N2L3G1 Canada
Siva Sivoththaman
Affiliation:
Center for Advanced Photovoltaic Devices and Systems (CAPDS), Waterloo, ON N2L3G1 Canada Electrical and Computer Engineering Department, University of Waterloo, Waterloo, ON N2L3G1 Canada
Get access

Abstract

In this work hydrophobicaly ligated cadmium selenide/zinc sulfide CdSe/ZnS quantum dots (QDs) were incorporated in transparent matrices by formation of CdSe/ZnS/SiO2 core/shell/shell structure using microemolsion synthesis method. The optical properties of the QDs encapsulated with a chemically grown oxide layers were studied. Intense luminescence properties of the QD/silica nanoparticles (NPs) were observed using steady state photoluminescence (PL) measurements. Confocal microscopy demonstrates fluorescence of the single core/shell/shell nanoparticles. The obtained results along with the Secondary Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images provide information on the geometry of the QDs. The excitonic emission of nanoparticles was also mapped using a liquid nitrogen cryostat the 77K - 300K range. The temperature dependent PL spectra of the film demonstrate the temperature-dependent band gap shrinkage of the QDs. PL lifetime measurements were performed on the ensemble of NPs. Experimental data was fitted to the numerical model with lifetime constants in nanoseconds range. We demonstrate that the main nonradiative processes that limit the quantum yield (QY) of the QDs at room temperature are the carrier trapping at the interface of QD/silica and the exciton-phonon coupling. These studies give us insight to exploit the QD layers for photon down shifting and multiple exciton generation for application in photovoltaics.

Type
Research Article
Copyright
Copyright © Materials Research Society 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Klimov, V. I., Alamos, L., Sci. 28, 214 (2003)Google Scholar
2. Murray, C. B., Kagan, C. R., and Bawendi, M. G., Sci. 270, 1335(1995).Google Scholar
3. Darbandi, M., Thomann, R., and Nann, T., Chem. Mater. 17, 5720 (2005)Google Scholar
4. Asare, K. O. and Arriagada, F. J., Colloids Surf. 50, 321(1990)Google Scholar
5. Banin, U., Bruchez, M., Alivisatos, A. P., Ha, T., Weiss, S., and Chemla, D. S., J. Chem. Phys. 110, 1195 (1999).Google Scholar
6. Giner, C. T., Debernardi, A., Cardona, M., Proupin, E. M., and Ekimov, A. I., Phys. Rev. B 57, 4664 (1998).Google Scholar