Cadmium Free Cu2ZnSnS4 Solar Cells with 9.7% Efficiency |
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Authors: | Jes K. Larsen,Fredrik Larsson,Tobias T rndahl,Nishant Saini,Lars Riekehr,Yi Ren,Adyasha Biswal,Dirk Hauschild,Lothar Weinhardt,Clemens Heske,Charlotte Platzer‐Bj rkman |
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Affiliation: | Jes K. Larsen,Fredrik Larsson,Tobias Törndahl,Nishant Saini,Lars Riekehr,Yi Ren,Adyasha Biswal,Dirk Hauschild,Lothar Weinhardt,Clemens Heske,Charlotte Platzer‐Björkman |
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Abstract: | Cu2ZnSnS4(CZTS) thin‐film solar cell absorbers with different bandgaps can be produced by parameter variation during thermal treatments. Here, the effects of varied annealing time in a sulfur atmosphere and an ordering treatment of the absorber are compared. Chemical changes in the surface due to ordering are examined, and a downshift of the valence band edge is observed. With the goal to obtain different band alignments, these CZTS absorbers are combined with Zn1?xSnxOy (ZTO) or CdS buffer layers to produce complete devices. A high open circuit voltage of 809 mV is obtained for an ordered CZTS absorber with CdS buffer layer, while a 9.7% device is obtained utilizing a Cd free ZTO buffer layer. The best performing devices are produced with a very rapid 1 min sulfurization, resulting in very small grains. |
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Keywords: | Cu2ZnSnS4 thermal treatment thin‐film solar cells valence bands |
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