| Autor: |
Blumenthal T; Department of Materials and Metallurgical Engineering, South Dakota School of Mines and Technology, 501 St Joseph Street, Rapid City, SD 57701, USA., Meruga J, Stanley May P, Kellar J, Cross W, Ankireddy K, Vunnam S, Luu QN |
| Jazyk: |
angličtina |
| Zdroj: |
Nanotechnology [Nanotechnology] 2012 May 11; Vol. 23 (18), pp. 185305. Date of Electronic Publication: 2012 Apr 13. |
| DOI: |
10.1088/0957-4484/23/18/185305 |
| Abstrakt: |
Two methods of direct-write printing for producing highly resolved features of a polymer impregnated with luminescent upconversion phosphors for security applications are presented. The printed polymer structures range in shape from features to text. The thin polymer features were deposited by direct-write printing of atomized material as well as by screen-printing techniques. These films contain highly luminescent lanthanide-doped, rare-earth nanocrystals, β-NaYF₄:3%Er, 17%Yb, which are capped with oleic acid. This capping agent allows the nanocrystals to disperse throughout the films for full detailing of printed features. Upconversion of deposited features was obtained using a 980 nm wavelength laser with emission of upconverted light in the visible region at both 540 and 660 nm. Features were deposited onto high bond paper, Kapton®, and glass to demonstrate possible covert and forensic security printing applications, as they are printed in various features and invisible to 'naked-eye' viewing at low concentrations of nanocrystals. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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