High quantum yield of the Egyptian blue family of infrared phosphors (MCuSi4O 10, M = Ca, Sr, Ba)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Shepherd Color Company, Cincinnati, OH (United States)
- PPG, Coatings Innovation Center, Allison Park, PA (United States)
The alkaline earth copper tetra-silicates, blue pigments, are interesting infrared phosphors. The Ca, Sr, and Ba variants fluoresce in the near-infrared (NIR) at 909, 914, and 948 nm, respectively, with spectral widths on the order of 120 nm. The highest quantum yield Φ reported thus far is ca. 10%. We use temperature measurements in sunlight to determine this parameter. The yield depends on the pigment loading (mass per unit area) ω with values approaching 100% as ω → 0 for the Ca and Sr variants. Although maximum quantum yield occurs near ω = 0, maximum fluorescence occurs near ω = 70 g m-2, at which Φ = 0.7. The better samples show fluorescence decay times in the range of 130 to 160 μs. The absorbing impurity CuO is often present. Good phosphor performance requires long fluorescence decay times and very low levels of parasitic absorption. In conclusion, the strong fluorescence enhances prospects for energy applications such as cooling of sunlit surfaces (to reduce air conditioning requirements) and luminescent solar concentrators.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
- Grant/Contract Number:
- AC02-05CH11231; EE0006347
- OSTI ID:
- 1461151
- Alternate ID(s):
- OSTI ID: 1437520
- Journal Information:
- Journal of Applied Physics, Vol. 123, Issue 19; ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Practical application of visible-induced luminescence and use of parasitic IR reflectance as relative spatial reference in Egyptian artifacts
|
journal | May 2019 |
Late production of Egyptian blue: synthesis from brass and its characteristics
|
journal | June 2019 |
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