Lateral heterojunction photodetector consisting of molecular organic and colloidal quantum dot thin films
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Bawendi_Lateral heterojunction.pdf
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Author(s)
Osedach, Timothy Paul
Geyer, Scott Mitchell
Ho, John C.
Arango, Alexi C.
Bawendi, Moungi G.
Bulovic, Vladimir
Date Issued
January 2009
Journal
Applied Physics Letters
Publisher
American Institute of Physics
Citation
Osedach, Tim P. et al. “Lateral heterojunction photodetector consisting of molecular organic and colloidal quantum dot thin films.” Applied Physics Letters 94.4 (2009): 043307-3. © 2009 American Institute of Physics
Version
Final published version
Abstract
We demonstrate a heterojunction photodetector of lateral geometry that utilizes an evaporated film of the hole-transporting molecular material N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)-9,9-spirobifluorene (spiro-TPD) as a charge transport layer and that is sensitized across visible wavelengths by a thin film of colloidal CdSe nanocrystal quantum dots (QDs). High photon-to-electron quantum conversion efficiencies are obtained at room temperature as a result of photoconductive gain. With an electric field of 3.0×10[superscript 5] V/cm applied across the electrodes, we measure the external quantum efficiency at the first QD absorption peak (at wavelength λ = 590 nm) to be 13%, corresponding to an internal quantum efficiency of approximately 80%. The operating mechanism of these devices is discussed, noting that the optical response is dominated by the QD absorption spectrum while the charge transport nearly exclusively takes place in the spiro-TPD.
Subjects
visible spectra
semiconductor thin films
semiconductor quantum dots
semiconductor heterojunctions
photodetectors
photoconductivity
organic compounds
nanostructured materials
II-VI semiconductors
hole mobility
electrodes
colloids
cadmium compounds
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1063/1.3075577
