Free charges produced by carrier multiplication in strongly coupled PbSe quantum dot films.

Aerts, Michiel; Suchand Sandeep, C S; Gao, Yunan; Savenije, Tom J; Schins, Juleon M; Houtepen, Arjan J; Kinge, Sachin; Siebbeles, Laurens D A · Nano Lett · 2011

basic_science · Level V

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Abstract

We show that in films of strongly coupled PbSe quantum dots multiple electron-hole pairs can be efficiently produced by absorption of a single photon (carrier multiplication). Moreover, in these films carrier multiplication leads to the generation of free, highly mobile charge carriers rather than excitons. Using the time-resolved microwave conductivity technique, we observed the production of more than three electron-hole pairs upon absorption of a single highly energetic photon (5.7E(g)). Free charge carriers produced via carrier multiplication are readily available for use in optoelectronic devices even without employing any complex donor/acceptor architecture or electric fields.