Screen-Printed Borosilicate Glass Derived from Sol-Gel Materials for Back-Contact Back-Junction Solar Cells

Borosilicate glass films deposited by chemical vapor deposition are used as boron dopant sources in silicon solar-cell manufacturing, to reduce the fabrication costs of, e.g., back-contact back-junction (BCBJ) solar cells. Herein, an alternative dopant source is investigated, which can replace such layers by a printing step. The necessary paste is synthesized by the sol-gel method and optimized for screen printing as demonstrated. The liquid paste can be converted to a glass by thermal annealing, as evaluated by spectroscopic investigations of the resulting thin films. The resulting layers are uniform and crack-free with a thickness of around 150 nm on silicon surfaces. It is shown that such layers can act as boron dopant sources on silicon, sufficient for the fabrication of BCBJ solar cells, as demonstrated by prototype devices.