Quantifying Recombination Losses for Perovskite Solar Cells
Recombination is one of the major loss processes in any solar cell. Solar cell optimiation therefore relies on characterization techniques to quantify recombination. Here a new approach is proposed based on voltage dependent photoluminescence.
Recombination losses in solar cells are a very important loss mechanism. Nevertheless, characterization of these losses happens primarily at open circuit, i.e. in the absence of current flow. This makes the data interpretation significantly easier. Quantifying recombination while significant currents flow in the solar cell are difficult as one is typically missing the information, whether a photon is just not absorbed or the photogenerated electron-hole pair has recombined before the charge carriers could reach their respective electrodes. To disentangle optical from electrical losses specific methods have to be developed. Grabowski et al. propose a novel approach based on measuring the current and the photoluminescence as a function of voltage at the same time that they apply to perovskite solar cells. A similar approach has also recently been shown to work for Cu(In,Ga)Se2 solar cells.
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