![]() The usual simulation setup for a solar cell with light at normal incidence is shown in the figure below:įor light incident at an angle it is recommended to use the Broadband Fixed Angle Source Technique (BFAST) as discussed in the Plasmonic solar cell at oblique incidence example. PML boundary conditions are required along the injection direction to absorb the reflected and transmitted fields. For the light source in the simulation you can use a plane wave with a wavelength range that covers the solar spectrum. In most cases, symmetric or antisymmetric boundary conditions can be used as well see Choosing between symmetric and anti-symmetric BCs for more information about symmetry settings. Usually solar cells can be modeled by periodic structures, which require only one unit cell and periodic boundary conditions for simulation. $$P a b s=-0.5 \text $$Īnd is commonly described as a percentage. The absorption per unit volume can be calculated from the divergence of the Poynting vector, Quantities to calculate from FDTD simulation Generation rate (g) and short circuit current (Jsc) Importing your own spectrum, while possible (see custom spectrum), will actually complicate your simulations and analysis. In fact, it is recommended to use the default source settings. It is not necessary to run a FDTD simulation with the solar spectrum. The other solar cell examples in this section use the same approach.Īn added benefit of this approach is that we can re-analyze the results using a different power spectrum, without having to run a new simulation. See the example script files for details. We simply multiply the impulse response of the system by the new power spectrum. Now that we have the impulse response of the system, it's easy to calculate the response to an arbitrary power spectrum. The data can now be correctly interpreted as the impulse response of the system. In effect, the CW Normalization has normalized away the spectrum of the source. By default (with CW Normalization enabled), the frequency domain data is automatically normalized AS IF the source injected the same amount of power at all frequencies. It is important to understand how to interpret this data. The FDTD source will automatically inject a spectrum calculated from a Gaussian-like shaped pulse, as shown in the Frequency/Wavelength tab (screenshot below).Īfter the simulation is complete, you can access the simulation data from frequency monitors with the standard functions like getdata, transmission, getelectric. It is not necessary to setup the spectrum of the FDTD source to match the desired power spectrum of your real source. ![]() Simply specify the wavelength range of interest (300-1000nm in this example). Setup your simulation in the normal way with "CW Normalization" selected (default setting). (note: it is easy to modify the code to include more solar spectrum in the UV direction) Step 1: Run your simulation in the normal way, with the standard source settings. This approach is summarized below, and demonstrated in the associated example files. We first simulate using the built-in source spectrum, and obtain the normalized quantities in frequency domain and then in post-processing, users can analyze any specific source spectrum, without running the simulation. It is relatively straightforward to include the effect of an arbitrary source power spectrum during your data analysis and post-processing.
0 Comments
Leave a Reply. |