FABRICATION AND CHARACTERISATION OF CRYSTALLINE SILICON WAFER SOLAR CELLS FOR TANDEM APPLICATIONS

Abstract

Today, crystalline silicon wafer solar cells are approaching their practical efficiency limit of about 28%. Higher efficiency can be achieved by a tandem cell approach that incorporates a high-bandgap top cell on top of a silicon bottom cell. In this configuration, the design considerations for the silicon cell are different from those of a stand-alone single-junction silicon cells operating under the AM1.5G 1-sun standard spectrum. Therefore, in this thesis two types of silicon cells are developed for applications as tandem bottom cells. One is a passivated-emitter-rear-contact silicon cell with planar front surface, achieving a stand-alone 1-sun efficiency of 16.8% and a 2-terminal perovskite-on-silicon tandem efficiency of 17.8%. The other cell type is a laser-fired-contact silicon cell that allows low-temperature rear-side metallization, which could be applied to both 2-terminal and 4-terminal tandem integrations. The stand-alone efficiency is 19.2% under 1-sun AM1.5G and 29.1% under a truncated infrared spectrum with 269.5W/m2. Detailed device fabrication and characterization results for both types of silicon solar cells are presented.