Samples with well replicated patterns established an average reflection of 1. Compared with the unpatterned ultraviolet-curable resin coating, the resulting sub-wavelength moth-eye structure also exhibited increased hydrophobicity in addition to antireflection. This R2P method is especially suitable for large-area product preparation and the biomimetic moth-eye structure with multiple performances can be applied to optical devices such as display screens, solar cells, or light emitting diodes. Download PDF Introduction Research of sub-wavelength structures on the surface of moth eyes led to the original understanding of antireflective AR phenomenon in nature.
|Published (Last):||24 November 2012|
|PDF File Size:||8.16 Mb|
|ePub File Size:||5.20 Mb|
|Price:||Free* [*Free Regsitration Required]|
However, such films are often narrow-band and even increase reflection for wavelengths outside their operating bandwidth. Nanostructures, on the other hand, can increase the efficiency of single-crystalline SC silicon solar cells over a wider range of wavelengths.
One such design is a bio-inspired structure array. In this example, we show how to setup such a simulation and measure the reflection versus the wavelength.
We can also gain insight into where the electromagnetic energy is absorbed and where the photoelectrons are created. The structure has a silicon substrate with a square lattice of silicon parabolic structures with period of nm. The moth eyes are drawn inside the structure group named "moth eye". We set x span and y span to be 0. We want to know how much power is absorbed in the moth eye structure, so we use two frequency-domain power monitors: R measure the total reflection, which is placed behind the source; T monitor is placed on the interface of moth eye and the substrate to measure the power into substrate.
The absorption in moth eye is 1-R-T. Broadband moth-eye AR coating Sources Our goal is to calculate the relative absorption of this structure using CW Normalization, therefore we use a plane wave with a wavelength range from nm to nm, instead of the real sunlight. If you want to calculate the absolute absorption, simply multiply the solar power see this page. Results First we can check that the simulation ran as expected. Right click the time monitor and choose Visualize "E", then the Visualizer plot the amplitude of E vs.
It can be seen that the fields eventually died down to the minimum shut-off criteria and that the simulation was not on its way to diverging. By choosing its x component, the Ex is plotted as below. The first section of the script plots the reflection, transmission, and fields absorbed by the conical structures. From the plot, we can see that wavelengths shorter than nm were mostly absorbed by the cones moth eye , and the wavelength greater than nm were mostly absorbed by the substrate.
The broadband reflectivity overall is quite low, as expected. The second section of the script, when enabled, plots the E 2 profile at the minimum and maximum wavelengths as well as the center wavelength. Notice that in the plot at nm, since the conic has high absorption, the E 2 field is very close to 0 at the conic-substrate interface.
Silicon solar cell with moth-eye anti-reflection coatings
Wafer-scale, subwavelength-structured nipple arrays are directly patterned on silicon using spin-coated silica colloidal monolayers as etching masks. The templated gratings exhibit excellent broadband antireflection properties and the normal-incidence specular reflection matches with the theoretical prediction using a rigorous coupled-wave analysis RCWA model. We further demonstrate that two common simulation methods, RCWA and thin-film multilayer models, generate almost identical prediction for the templated nipple arrays. This simple bottom-up technique is compatible with standard microfabrication, promising for reducing the manufacturing cost of crystalline silicon solar cells.
Broadband moth-eye antireflection coatings on silicon
Also, the layer will have the ideal thickness for only one distinct wavelength of light. The value of R varies from 0 no reflection to 1 all light reflected and is usually quoted as a percentage. Reflection can be reduced by texturing the surface with 3D pyramids or 2D grooves gratings. Artificial moth eyes enhance the performance of silicon solar cells You can help by adding to it. Retrieved Jan 22, A similar method is used in fibre optic research, where an index-matching oil is sometimes used to temporarily defeat total internal reflection so that light may be coupled into or out of a fiber. Archived from the original PDF on 12 January Sign in to get notified via email when antireflectioh comments are made. One way to do this is to add a second quarter-wave thick higher-index layer between the low-index layer and the substrate.