title: Charge Dynamics in Solution-Processed Nanocrystalline CuInS2 Solar Cells.
abstract: We investigate charge dynamics in solar cells constructed using solution-processed layers of CuInS2 (CIS) nanocrystals (NCs) as the electron donor and CdS as the electron acceptor. By using time-resolved spectroscopic techniques, we are able to observe photoinduced absorptions that we attribute to the mobile hole carriers in the NC film. In combination with transient photocurrent and photovoltage measurements, we monitor charge dynamics on time scales from 300 fs to 1 ms. Carrier dynamics are investigated for devices with CIS layers composed of either colloidally synthesized 1,3-benzenedithiol-capped nanocrystals or in situ sol-gel synthesized thin films as the active layer. We find that deep trapping of holes in the colloidal NC cells is responsible for decreases in the open-circuit voltage and fill factor as compared to those of the sol-gel synthesized CIS/CdS cell.
authors.affiliation: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Halpert
authors.affiliation: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Frederik S F
authors.initials: FS
authors.lastname: Morgenstern
authors.affiliation: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Bruno
authors.initials: B
authors.lastname: Ehrler
authors.affiliation: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Yana
authors.initials: Y
authors.lastname: Vaynzof
authors.affiliation: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Dan
authors.initials: D
authors.lastname: Credgington
authors.affiliation: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Neil C
authors.initials: NC
authors.lastname: Greenham
keywords: CIS; charge transfer; cupric chalcogenides; nanocrystals; photovoltaics; quantum dot; transient absorption; trapping