Abstract
In contrast to traditional semiconductors, conjugated polymers provide ease of processing, low cost, physical flexibility and large area coverage 1. These active optoelectronic materials produce and harvest light efficiently in the visible spectrum. The same functions are required in the infrared for telecommunications (1,300-1,600 nm), thermal imaging (1,500 nm and beyond), biological imaging (transparent tissue windows at 800 nm and 1,100nm), thermal photovoltaics (>1,900nm), and solar cells (800-2,000 nm). Photoconductive polymer devices have yet to demonstrate sensitivity beyond -800 nm (refs 2,3). Sensitizing conjugated polymers with infrared-active nanocrystal quantum dots provides a spectrally tunable means of accessing the infrared while maintaining the advantageous properties of polymers. Here we use such a nanocomposite approach in which PbS nanocrystals tuned by the quantum size effect sensitize the conjugated polymer poly[2-methoxy-5-(2′- ethylhexyloxy-p-phenylenevinylene)] (MEH-PPV) into the infrared. We achieve, in a solution-processed device and with sensitivity far beyond 800 nm, harvesting of infrared-photogenerated carriers and the demonstration of an infrared photovoltaic effect. We also make use of the wavelength tunability afforded by the nanocrystals to show photocurrent spectra tailored to three different regions of the infrared spectrum.
Original language | English (US) |
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Pages (from-to) | 138-142 |
Number of pages | 5 |
Journal | Nature materials |
Volume | 4 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2005 |
Funding
We thank S. Hoogland for discussions and the following for support: the Government of Ontario through the Ontario Graduate Scholarships program (S.A.M.); Materials and Manufacturing Ontario, a division of the Ontario Centres of Excellence; the Natural Sciences and Engineering Research Council of Canada through its Collaborative Research and Development Program; Nortel Networks; the Canada Foundation for Innovation; the Ontario Innovation Trust; and the Canada Research Chairs Programme. Correspondence and requests for materials should be addressed to E.H.S. Supplementary Information accompanies the paper on www.nature.com/naturematerials.
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- General Materials Science