Energy Structure of CdSe/CdTe Type II Colloidal Quantum Dots - Do Phonon Bottlenecks Remain for Thick Shells?

Charles T. Smith; Edward J. Tyrrell; Marina A. Leontiadou; Jacek Miloszewski; Thomas Walsh; Musa Cadirci; Robert Page; Paul O'Brien; David Binks; Stanko Tomic

doi:10.1016/j.solmat.2015.12.015

Energy Structure of CdSe/CdTe Type II Colloidal Quantum Dots - Do Phonon Bottlenecks Remain for Thick Shells?

Charles T. Smith, Edward J. Tyrrell, Marina A. Leontiadou, Jacek Miloszewski, Thomas Walsh, Musa Cadirci, Robert Page, Paul O'Brien, David Binks, Stanko Tomic

Research output: Contribution to journal › Article › peer-review

Abstract

The excitonic structure of CdSe/CdTe type II colloidal quantum dots is predicted using a model based on k.p theory and the many{particle configuration interaction method, with proper treatment of the polarization effects at the core{shell interface and at the dot surface. The separation of energy levels in the conduction band is examined and used to identify phonon bottlenecks, and how these evolve as the shell thickness is increased. Bottlenecks are found to persist both above and below the threshold for multiple exciton generation for all the shell thicknesses investigated. The overall electron cooling rate is thus expected to fall as the shell thickness is increased, and this is confirmed experimentally using ultrafast transient absorption measurements.

Original language	English
Journal	Solar Energy Materials & Solar Cells
DOIs	https://doi.org/10.1016/j.solmat.2015.12.015
Publication status	Published - 2015

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10.1016/j.solmat.2015.12.015

1 Chapter

Charge Dynamics in Colloidal Quantum Dots: Recombination, Trapping and Multiple Exciton Generation
Leontiadou, M., Smith, C., Lydon, C. & Binks, D., 2018, Nanostructured Materials for Type III Photovoltaics. Skabara, P. & Malik, M. A. (eds.). Cambridge: Royal Society of Chemistry, p. 472-507 (Nanoscience and Nanotechnology).
Research output: Chapter in Book/Report/Conference proceeding › Chapter

Cite this

@article{51b31871731a48a59fa1226a95e44e80,

title = "Energy Structure of CdSe/CdTe Type II Colloidal Quantum Dots - Do Phonon Bottlenecks Remain for Thick Shells?",

abstract = "The excitonic structure of CdSe/CdTe type II colloidal quantum dots is predicted using a model based on k.p theory and the many{particle configuration interaction method, with proper treatment of the polarization effects at the core{shell interface and at the dot surface. The separation of energy levels in the conduction band is examined and used to identify phonon bottlenecks, and how these evolve as the shell thickness is increased. Bottlenecks are found to persist both above and below the threshold for multiple exciton generation for all the shell thicknesses investigated. The overall electron cooling rate is thus expected to fall as the shell thickness is increased, and this is confirmed experimentally using ultrafast transient absorption measurements.",

author = "Smith, {Charles T.} and Tyrrell, {Edward J.} and Leontiadou, {Marina A.} and Jacek Miloszewski and Thomas Walsh and Musa Cadirci and Robert Page and Paul O'Brien and David Binks and Stanko Tomic",

note = "The authors acknowledge the EPSRC UK grant {"}Enhanced multiple exciton generation in colloidal quantum dots{"} (EP/K008587/1) for financial support. We also acknowledge the EU-COST project {"}MultiscaleSolar{"} (MP1406) and the Royal Society grant {"}High Performance Computing in Modelling of Innovative Photo-Voltaic Devices{"}. We acknowledge help from the N8 Research Partnership and Science and Technology Facilities Council for providing the computational resources used to conduct this research. We would also like to express our gratitude to W. Flavell for useful discussions.",

year = "2015",

doi = "10.1016/j.solmat.2015.12.015",

language = "English",

journal = "Solar Energy Materials & Solar Cells",