a selective absorbing emitter

Abstract

A selective absorbing emitter disclosed by the present invention comprises a substrate, a metal film covered on the substrate, and a unit array arranged on the metal film, and the unit array is composed of a plurality of basic units arranged at intervals with the same external dimensions , each basic unit is composed of a number of stacks stacked sequentially from top to bottom, each stack includes a metal layer and a dielectric layer or two dielectric layers with different refractive indices on the lower side of the metal layer, each basic The angle between the side of the unit and the normal line of the substrate is -80-80°. The selective absorption emitter is a broadband absorption emitter with wavelength selectivity. Its working wavelength has little correlation with the diameter or length of the top and bottom of the basic unit in the unit array, and has low requirements on the precision of the preparation technology. When its working wavelength is in the 8-13 μm band and has high absorption and emission rates, it can be used for Passive radiative cooling can also obtain the desired absorption characteristics in other wavelength ranges by changing the array design parameters.

Description

technical field [0001] The invention belongs to the field of photoelectric and photothermal functional materials and devices, and in particular relates to a selective absorption emitter. Background technique [0002] Kirchhoff's thermal radiation law is used to describe the relationship between the emissivity and absorptivity of an object, which states that at the same temperature, the ratio of the monochromatic radiation flux density to the monochromatic absorptivity of different objects for the same wavelength is the same as the The monochromatic radiation flux density of a black body at the same wavelength is equal at temperature, that is, the absorptivity is equal to the emissivity. It shows that the more radiating an object is, the more absorbing it is, and vice versa. [0003] Thermal radiation is a non-contact heat transfer method, which relies on electromagnetic wave radiation to achieve energy transfer between hot and cold objects, even in a vacuum. In 2014, the r...

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Problems solved by technology

In 2015, Australia's Min Gu research team reported in Advanced Optical Materials (volume 3, page 1047) an infrared thermal emitter based on a hyperbolic metamaterial, which has an average emissivity of 0.8 in the atmospheric transparent window, higher than 0.67 for the multilayer film system, however, the researchers did not test the passive radiative cooling properties of the metamaterial

In fact, although the use of more materials will bring greater design freedom, it will also be limited by the type of materials, and the design dielectric constant may not have a corresponding material in nature, and it may further increase the experimental equipment. complexity and cost of manufacturing

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