Multiple-exciton generation in lead selenide nanorod solar cells with external quantum efficiencies exceeding 120.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 26411283.
- Also identified by DOI 10.1038/ncomms9259 and PMC identifier 4667436.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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.