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Multiple-exciton generation in lead selenide nanorod solar cells with external quantum efficiencies exceeding 120.


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Authors

Davis, Nathaniel JLK 
Böhm, Marcus L 
Wisnivesky-Rocca-Rivarola, Florencia 

Abstract

Multiple-exciton generation-a process in which multiple charge-carrier pairs are generated from a single optical excitation-is a promising way to improve the photocurrent in photovoltaic devices and offers the potential to break the Shockley-Queisser limit. One-dimensional nanostructures, for example nanorods, have been shown spectroscopically to display increased multiple exciton generation efficiencies compared with their zero-dimensional analogues. Here we present solar cells fabricated from PbSe nanorods of three different bandgaps. All three devices showed external quantum efficiencies exceeding 100% and we report a maximum external quantum efficiency of 122% for cells consisting of the smallest bandgap nanorods. We estimate internal quantum efficiencies to exceed 150% at relatively low energies compared with other multiple exciton generation systems, and this demonstrates the potential for substantial improvements in device performance due to multiple exciton generation.

Description

Keywords

1007 Nanotechnology, 0906 Electrical and Electronic Engineering, 0205 Optical Physics

Journal Title

Nat Commun

Conference Name

Journal ISSN

2041-1723
2041-1723

Volume Title

6

Publisher

Springer Science and Business Media LLC
Sponsorship
Engineering and Physical Sciences Research Council (EP/G060738/1)
Engineering and Physical Sciences Research Council (EP/M005143/1)
Engineering and Physical Sciences Research Council (EP/G037221/1)
European Research Council (259619)
European Commission (312483)
NJLKD thanks the Cambridge Commonwealth European and International Trust, Cambridge Australian Scholarships and Mr Charles K Allen for financial support. MLB thanks the German National Academic Foundation (“Studienstiftung”) for financial support. MT thanks the Gates Cambridge Trust, EPSRC and Winton Programme for Sustainability for financial support. F.W.R.R. gratefully thanks financial support from CNPq [Grant number 246050/2012-8]. C.D. acknowledges financial support from the EU [Grant number 312483 ESTEEM2]. This work was supported by the EPSRC [Grant numbers EP/M005143/1, EP/G060738/1, EP/G037221/1] and the ERC [Grant number 259619 PHOTO-EM].