Si solid-state quantum dot-based materials for tandem solar cells.

Content Provider	Europe PMC
Author	Conibeer, Gavin Perez-Wurfl, Ivan Hao, Xiaojing Di, Dawei Lin, Dong
Copyright Year	2012
Abstract	The concept of third-generation photovoltaics is to significantly increase device efficiencies whilst still using thin-film processes and abundant non-toxic materials. A strong potential approach is to fabricate tandem cells using thin-film deposition that can optimise collection of energy in a series of cells with decreasing band gap stacked on top of each other. Quantum dot materials, in which Si quantum dots (QDs) are embedded in a dielectric matrix, offer the potential to tune the effective band gap, through quantum confinement, and allow fabrication of optimised tandem solar cell devices in one growth run in a thin-film process. Such cells can be fabricated by sputtering of thin layers of silicon rich oxide sandwiched between a stoichiometric oxide that on annealing crystallise to form Si QDs of uniform and controllable size. For approximately 2-nm diameter QDs, these result in an effective band gap of 1.8 eV. Introduction of phosphorous or boron during the growth of the multilayers results in doping and a rectifying junction, which demonstrates photovoltaic behaviour with an open circuit voltage (VOC) of almost 500 mV. However, the doping behaviour of P and B in these QD materials is not well understood. A modified modulation doping model for the doping mechanisms in these materials is discussed which relies on doping of a sub-oxide region around the Si QDs.
ISSN	19317573
Journal	Nanoscale Research Letters
Volume Number	7
PubMed Central reference number	PMC3337243
Issue Number	1
PubMed reference number	22436303
e-ISSN	1556276X
DOI	10.1186/1556-276x-7-193
Language	English
Publisher	Springer
Publisher Date	2012-03-21
Access Restriction	Open
Rights License	This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright ©2012 Conibeer et al; licensee Springer.
Subject Keyword	band gap engineering quantum dots photovoltaics tandem cells modulation doping nucleation third generation
Content Type	Text
Resource Type	Article
Subject	Nanoscience and Nanotechnology Condensed Matter Physics Materials Science