Charge dynamics at heterojunctions for PbS/ZnO colloidal quantum dot solar cells probed with time-resolved surface photovoltage spectroscopy

Spencer, BF, Leontiadou, M ORCID: https://orcid.org/0000-0003-2616-1841, Clark, PCJ, Williamson, AI, Silly, MG, Sirotti, F, Fairclough, SM, Tsang, SCE, Neo, DCJ, Assender, HE, Watt, AAR and Flavell, WR 2016, 'Charge dynamics at heterojunctions for PbS/ZnO colloidal quantum dot solar cells probed with time-resolved surface photovoltage spectroscopy' , Applied Physics Letters, 108 (9) , 091603.

[img]
Preview
PDF - Published Version
Available under License Creative Commons Attribution.

Download (1MB) | Preview

Abstract

Time-resolved laser-pump X-ray-photoemission-probe spectroscopy of a ZnO (101 ⎯ ⎯ 0 101¯0 ) substrate with and without PbS quantum dots (QDs) chemically linked to the surface is performed, using laser photon energies resonant with and below the band gap energy of the substrate (λ = 372 and 640 nm, hν = 3.33 and 1.94 eV). Charge injection from the photoexcited QDs to ZnO is demonstrated through the change in the surface photovoltage of the ZnO substrate observed when the heterojunction is illuminated with 1.94 eV radiation. The measured carrier dynamics are limited by the persistent photoconductivity of ZnO, giving dark carrier lifetimes of the order of 200 μs in a depletion layer at the interface. The chemical specificity of soft X-rays is used to separately measure the charge dynamics in the quantum dots and the substrate, yielding evidence that the depletion region at the interface extends into the PbS QD layer.

Item Type: Article
Schools: Schools > School of Computing, Science and Engineering
Journal or Publication Title: Applied Physics Letters
Publisher: AIP Publishing
ISSN: 0003-6951
Related URLs:
Funders: Engineering and Physical Sciences Research Council (EPSRC)
Depositing User: Dr MARINA LEONTIADOU
Date Deposited: 01 Apr 2019 14:14
Last Modified: 01 Apr 2019 14:15
URI: http://usir.salford.ac.uk/id/eprint/50828

Actions (login required)

Edit record (repository staff only) Edit record (repository staff only)

Downloads

Downloads per month over past year