Ultrafine chromium particles for photothermal conversion of solar energy
- 1 June 1978
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 49 (6), 3512-3520
- https://doi.org/10.1063/1.325263
Abstract
Individually isolated chromium particles were prepared by evaporation onto KBr plates in a mixture of argon and air. Such coatings were taken as a model substance simulating the properties of electrodeposited chromium black—a well‐known material for efficient photothermal conversion of solar energy. Median diameters of the particles were 5–13 nm; their shapes were spherical or cubelike. Optical transmittance at normal incidence was recorded by spectrophotometry in the interval 0.3–25 μm. Excellent spectral selectivity was documented with high absorptance over the wavelength range for solar radiation and high transmittance further out in the infrared. The optical data were interpreted within the Maxwell Garnett theory, which was generalized so as to encompass dipole‐dipole coupling among aggregated spheres, cubelike shapes, and oxide pellicles. Agreement between theory and experiments was achieved by considering aggregation of spherical particles into linear chains. The effects of having cubic particles, as well as oxide‐coated spherical ones, were calculated and found to be rather unimportant for understanding the spectral selectivity.Keywords
This publication has 62 references indexed in Scilit:
- Optical properties of ultrafine gold particlesPhysical Review B, 1977
- Applications of thin graded-index films to solar absorbersApplied Optics, 1977
- Selective nature of gold-black depositsJournal of the Optical Society of America, 1976
- Application of thin films to solar energy utilizationJournal of Vacuum Science and Technology, 1976
- Statistical model for coalescence of islands in discontinuous filmsApplied Physics Letters, 1975
- A statistical theory of the dielectric properties of thin island films: I. The surface material coefficientsPhysica, 1974
- A phenomenological theory of the dielectric properties of thin filmsPhysica, 1973
- Reflection and transmission of light by a square non-polar latticePhysica, 1973
- Determination of the Optical Constants of Uniaxial or Isotropic Metals by Measurement of Reflectance Ratios*Journal of the Optical Society of America, 1968
- Absorption of Low-Energy Photons in the Transition Metals*Journal of the Optical Society of America, 1967