By Yuhong Cao, R&D Centre, China Sunergy (Nanjing) PV-Tech Co,. Ltd.; Jilei Wang, R&D Centre, China Sunergy (Nanjing) PV-Tech Co,. Ltd.; Zhichun Ni, Director of R&D, China Sunergy (Nanjing) PV-Tech Co,. Ltd.; Jianhua Zhao, China Sunergy (Nanjing) PV-Tech Co,. Ltd.; Aihua Wang, China Sunergy (Nanjing) PV-Tech Co,. Ltd.
The aim of this work is to study the effects of dark lines on the face of polycrystalline silicon solar cells. The formative processes of dark lines were observed by laser scanning microscopy. Following the initial appearance of a few etch pits on the surface of the cells, extending the etching time saw these etch pits increase in size, eventually merging to form a single line, known as a ‘dark line’. Dark lines are lines that are linked together by a series of contiguous dislocation outcrops and have the potential to reduce silicon wafer lifetime, adversely affect both the electroluminescence and the quantum efficiency of a solar cell, and have resulting negative effects on the cell’s electrical properties.
