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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<h1> Refractive Index Information DB </h1>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from solcore.absorption_calculator.nk_db import download_db, search_db\n",
    "from solcore import material\n",
    "from solcore import si\n",
    "from solcore.solar_cell import SolarCell\n",
    "from solcore.structure import Layer\n",
    "from solcore.solar_cell_solver import solar_cell_solver, default_options\n",
    "\n",
    "import numpy as np\n",
    "import matplotlib.pyplot as plt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "wl = si(np.arange(100, 900, 10), 'nm')\n",
    "\n",
    "opts = default_options\n",
    "opts.optics_method = 'TMM'\n",
    "opts.wavelength = wl"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Download the database from refractiveindex.info. This only needs to be done once.\n",
    "Can specify the source URL and number of interpolation points."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "download_db()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Can search the database to select an appropriate entry. Search by element/chemical formula.\n",
    "In this case, look for silver."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "search_db('Ag', exact = True)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This prints out, line by line, matching entries. This shows us entries with\n",
    "\"pageid\"s 0 to 14 correspond to silver.\n",
    "\n",
    "Let's compare the optical behaviour of some of those sources:\n",
    "pageid = 0, Johnson\n",
    "pageid = 2, McPeak\n",
    "pageid = 8, Hagemann\n",
    "pageid = 12, Rakic (BB)\n",
    "\n",
    "\n",
    "create instances of materials with the optical constants from the database.\n",
    "The name (when using Solcore's built-in materials, this would just be the\n",
    "name of the material or alloy, like 'GaAs') is the pageid, AS A STRING, while\n",
    "the flag nk_db must be set to True to tell Solcore to look in the previously\n",
    "downloaded database from refractiveindex.info"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "Ag_Joh = material(name = '0', nk_db=True)()\n",
    "\n",
    "Ag_McP = material(name = '2', nk_db=True)()\n",
    "Ag_Hag = material(name = '8', nk_db=True)()\n",
    "Ag_Rak = material(name = '12', nk_db=True)()\n",
    "\n",
    "Ag_Sol = material(name = 'Ag')() # Solcore built-in (from SOPRA)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "plot the n and k data. Note that not all the data covers the full wavelength range,\n",
    "so the n/k value stays flat."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "names = ['Johnson', 'McPeak', 'Hagemann', 'Rakic', 'Solcore built-in']\n",
    "\n",
    "plt.figure()\n",
    "plt.plot(wl * 1e9, Ag_Joh.n(wl), wl * 1e9, Ag_McP.n(wl),\n",
    "         wl * 1e9, Ag_Hag.n(wl), wl * 1e9, Ag_Rak.n(wl), wl * 1e9, Ag_Sol.n(wl))\n",
    "plt.legend(labels=names)\n",
    "plt.xlabel(\"Wavelength (nm)\")\n",
    "plt.ylabel(\"n\")\n",
    "plt.show()\n",
    "\n",
    "plt.figure()\n",
    "plt.plot(wl * 1e9, Ag_Joh.k(wl), wl * 1e9, Ag_McP.k(wl),\n",
    "         wl * 1e9, Ag_Hag.k(wl), wl * 1e9, Ag_Rak.k(wl), wl * 1e9, Ag_Sol.k(wl))\n",
    "plt.legend(labels=names)\n",
    "plt.xlabel(\"Wavelength (nm)\")\n",
    "plt.ylabel(\"k\")\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Compare performance as a back mirror on a GaAs 'cell'\n",
    "\n",
    "Solid line: absorption in GaAs\n",
    "Dashed line: absorption in Ag"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "GaAs = material('GaAs')()\n",
    "\n",
    "colors = ['b', 'r', 'k', 'm', 'y']\n",
    "\n",
    "plt.figure()\n",
    "for c, Ag_mat in enumerate([Ag_Joh, Ag_McP, Ag_Hag, Ag_Rak, Ag_Sol]):\n",
    "    my_solar_cell = SolarCell([Layer(width=si('50nm'), material = GaAs)] +\n",
    "                            [Layer(width = si('100nm'), material = Ag_mat)])\n",
    "    solar_cell_solver(my_solar_cell, 'optics', opts)\n",
    "    GaAs_positions = np.linspace(my_solar_cell[0].offset, my_solar_cell[0].offset + my_solar_cell[0].width, 1000)\n",
    "    Ag_positions = np.linspace(my_solar_cell[1].offset, my_solar_cell[1].offset + my_solar_cell[1].width, 1000)\n",
    "    GaAs_abs = np.trapz(my_solar_cell[0].diff_absorption(GaAs_positions), GaAs_positions)\n",
    "    Ag_abs = np.trapz(my_solar_cell[1].diff_absorption(Ag_positions), Ag_positions)\n",
    "    plt.plot(wl*1e9, GaAs_abs, color=colors[c], linestyle='-', label=names[c])\n",
    "    plt.plot(wl*1e9, Ag_abs, color=colors[c], linestyle='--')\n",
    "\n",
    "plt.legend()\n",
    "plt.xlabel(\"Wavelength (nm)\")\n",
    "plt.ylabel(\"Absorbed\")\n",
    "plt.show()"
   ]
  }
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