Dual wavelength (ultraviolet and green) photodetectors using solution processed Zinc Oxide nanoparticles


Narrow-band photoconductivity with a spectral width of 0.16 eV is obtained from solution-processed colloidal ZnO nanocrystals beneath the band-edge at 2.25 eV. A new model involving electron transfer from deep defects to discrete shallow donors is introduced to explain the narrow spectrum and the exponential form of the current rise and decay transients. The defects are tentatively assigned to neutral oxygen vacancies. The photocurrent responsivity can be enhanced by storage in air and this correlates with the formation of carbonate surface species by capture of carbon dioxide during storage. This controllability is exploited to develop a low-cost and scalable photolithographic approach to pixelate photodetectors for applications such as object discrimination, sensing etc. The spectral response can be spatially patterned so that dual (ultraviolet and green) and single (ultraviolet only) wavelength detecting ZnO pixels can be produced on the same substrate. This presents a new sensor mode with applications in security or full colour imaging.

Publication DOI: https://doi.org/10.1021/acsami.7b08092
Dataset DOI: https://doi.org/10.17036/researchdata.aston.ac.uk.00000296
Divisions: Engineering & Applied Sciences
Engineering & Applied Sciences > Energy and Bioproducts Research Institute (EBRI)
Additional Information: Copyright © 2017 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acsami.7b08092. Funding: Iraqi Ministry of Higher Education and Scientific Research, EPSRC grant EP/J001597/1.
Uncontrolled Keywords: persistent photoconductivity ,ZnO nanoparticles ,photolithography ,imaging photodetectors ,defects
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Related URLs: http://pubs.acs ... /acsami.7b08092 (Publisher URL)
PURE Output Type: Article
Published Date: 2017-10-25
Published Online Date: 2017-09-26
Accepted Date: 2017-09-26
Authors: Ibrahem, Mohammed
Verrelli, Emanuele
Lai, Khue
Kyriakou, Georgios
Lee, Adam
Isaacs, Mark
Cheng, Fei
O'Neill, Mary


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