One of the main limiting factors of solar cell efficiency is charge carrier recombination at the interfaces of the absorber material. The recombining carriers neither contribute to the current generation nor to the voltage buildup and hence nor to the power output of the device. Even in crystalline silicon (cSi) solar cells based on passivating contacts—which enable record efficiencies [16]—recombination via surface defects is an issue. Surface passivation relies on the reduction of these defects (chemical passivation) and the repulsion of minoritycarriers from the defective interfaces (field effect passivation). While chemical passivation is dictated by the material directly applied on the cSi wafer surface, field effect passivation may additionally be influenced by layers which are offset from the wafer surface and used to induce carrierselectivity or to extract carriers. In the present study, we investigate the effect of different materials on passivation in more detail using quasisteadystate photoluminescence (QSSPL) [7, 8]. In contrast to the traditional method, QSSPL overcomes the challenge of measuring the injectiondependent effective minoritycarrier lifetime (eff) of metallized samples. This enables us to disentangle the impact of each individual material in the sample, including any metallic layers. With this technique, we seek to determine the effect each material has on device performance through their influence on recombination at both room temperature and at elevated operating temperatures (T). We focus on the impact of various metallisation schemes and examine a range of materials often used for cSi solar cells, namely undoped or doped passivation and chargecollecting layers (e.g. aluminium oxide and hydrogenated amorphous silicon), and transparent conductive oxides (e.g. indium tin oxide).
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