Detection of finger interruptions in silicon solar cells using photoluminescence imaging

Since publication, it has been brought to the attention of the Editorial Office of Chinese Physics B that parts of this paper showed strong similarities to the following article (including one equation, some analyses, the motivation and the conclusion) without citation: “Detection of Finger Interruptions in Silicon Solar Cells Using Line Scan Photoluminescence Imaging,” IEEE Journal of Photovoltaics, 2017, vol. 7, No. 6, pp. 1496-1502. Following our investigation, this article has been retracted by the Editorial Office of Chinese Physics B.

Finger interruptions are common problems in screen printed solar cells, resulting in poor performance in efficiency because of high effective series resistance. Electroluminescence (EL) imaging is typically used to identify interrupted fingers. In this paper, we demonstrate an alternative method based on photoluminescence (PL) imaging to identify local series resistance defects, with a particular focus on finger interruptions. Ability to detect finger interruptions by using PL imaging under current extraction is analyzed and verified. The influences of external bias control and illumination intensity on PL images are then studied in detail. Finally, in comparison with EL imaging, the using of PL imaging to identify finger interruptions possesses the prominent advantages:in PL images, regions affected by interrupted fingers show higher luminescence intensity, while regions affected by recombination defects show lower luminescence intensity. This inverse signal contrast allows PL imaging to more accurately identify the defect types.