Dielectric surface passivation for silicon solar cells: A review

Silicon wafer solar cells continue to be the leading photovoltaic technology, and in many places are now providing a substantial portion of electricity generation. Further adoption of this technology will require processing that minimises losses in device performance. A fundamental mechanism for efficiency loss is the recombination of photo‐generated charge carriers at the unavoidable cell surfaces. Dielectric coatings have been shown to largely prevent these losses through a combination of different passivation mechanisms. This review aims to provide an overview of the dielectric passivation coatings developed in the past two decades using a standardised methodology to characterise the metrics of surface recombination across all techniques and materials. The efficacy of a large set of materials and methods has been evaluated using such metrics and a discussion on the current state and prospects for further surface passivation improvements is provided. In order to continue to decrease cost and improve performance of silicon solar cells it is essential to minimize electrical losses due to the recombination of electron–hole pairs at cell surfaces. The most common approach is the application of a dielectric coating to suppress these losses, which occur via a combination of different mechanisms. This review article examines the range of dielectric coatings developed in the last two decades and how these coatings act to increase cell performance.