A photonic crystal cascaded structure to improve the far-field emission efficiency of quantum dots

Abstract

The invention provides a photonic crystal cascade structure improving far field emission efficiency of quantum dots. The surface of a substrate which is made of low refraction index materials and has two-dimensional periodic arranged circular holes is coated with a layer of high refraction index materials, four layers of the structures are in cascade connection in the vertical direction with equal space, the interlamination and the circular hole parts of the lower three layers are filled with the low refraction index materials, and the top layer circular holes are air vent holes. The fact that a photonic crystal leakage mode, quantum dot light absorption and fluorescence emission are coupled at wave length efficiently can be achieved by optimizing hole depth, thickness of the refractive index materials and interlayer spacing. The quantum dots are embedded in the position of a photonic crystal cascade structure top leakage mode, light absorption and fluorescence extraction efficiency can be improved, and the sensitivity of a quantum dot sensor and the far field emission efficiency of luminescent devices can be improved. Through the adoption of the photonic crystal cascade structure improving the far field emission efficiency of the quantum dots, the problem that a traditional optical coupling structure cannot improve the far field emission efficiency of double-fluorescence-peak quantum dots in a two-emission-wavelength range or of the single-fluorescence-peak quantum dots with different light emission wave lengths.

Description

technical field [0001] The invention relates to a photonic crystal cascaded structure, in particular to a photonic crystal leakage mode that is efficiently coupled with quantum dot light absorption and fluorescence emission at wavelengths to improve double fluorescence peak quantum dots or single fluorescence peak quantum dots with different emission wavelengths. Photonic crystal cascade structures for point far-field emission efficiency. Background technique [0002] Colloidal quantum dots are widely used in LEDs, fluorescent biological probes, pharmaceutical chemical sensing, and temperature sensing due to their high quantum efficiency and good photostability. Researchers have conducted detailed studies on the luminous intensity and wavelength of quantum dots with a single fluorescent peak. Recently, dual fluorescence peak quantum dots (such as manganese-doped colloidal quantum dots: Zn 1-x mn x Se / ZnCdSe or Zn 1-x mn x Se / ZnS / CdS / ZnS) has attracted great attention of...

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Problems solved by technology

[0006] Based on the above prior art, the object of the present invention is to provide a photonic crystal cascade structure that improves the far-field emission efficiency of quantum dots, which can improve the performance of double fluorescence peak quantum dots or single fluorescence peak quantum dots with different emission wavelengths in a wide wavelength range. The far-field emission efficiency of colloidal quantum dots in the two emission wavelength ranges can not be improved to solve the problem that the ordinary one-dimensional photonic crystal or single-layer two-dimensional photonic crystal structure can not improve the far-field fluorescence emission efficiency in the two emission wavelength ranges.

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