March 20, 2009

Hybrid Photovoltaics

Hybrid Photovoltaics

A research team from Los Alamos National Laboratory (US) has demonstrated an example of hybrid photovoltaic (PV) structures (see figure) that combine colloidal semiconductor nanocrystals (NCs) with amorphous silicon. In these structures, NCs and silicon are electronically coupled and the regime of this coupling can be tuned by altering the alignment of NC energy states with regard to silicon band edges. For example, using wide-bandgap CdSe NCs they demonstrated a photoresponse, which is exclusively due to the NCs. Conversely, in devices comprising narrow-bandgap PbS NCs, both the NCs and silicon contribute to the photocurrent, which results in the PV response extending from the visible to the near-infrared region. The hybrid silicon/PbS NC solar cells show external quantum efficiencies of ≈7% at infrared energies and ≈50% in the visible and a power conversion efficiency of up to 0.9%. Consequently, this work demonstrates the feasibility of hybrid PV devices that combine advantages of mature silicon fabrication technologies with the unique electronic properties of semiconductor NCs.

B. Sun, A. T. Findikoglu, M. Sykora, D. J. Werder, V. I. Klimov, Nano Lett. Web Publication Date 11 February 2009, DOI: 10.1021/nl9001469.

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