Fabrication and analysis of ultra-thin Si solar cell

Abstract

In this thesis, the fabrication process of a 20 μm mono-crystalline silicon solar cell on steel substrate was developed. This epitaxially grown solar cell has the benefit of minimizing silicon material losses, as well as the potential to achieve high open-circuit voltage due to reduced bulk recombination. The best large area UTSi solar cell was fabricated with an area of 90 cm2. It has a confirmed efficiency of 15.9%, VOC of 632 mV, JSC of 33.7 mA/cm2 and FF of 75%. The first UTSi mini module was also made with four 100 cm2 UTSi cells, demonstrating excellent flexibility and weigh per watt ratio of just 45 g/Wp after lamination. A detailed 3-dimensional device model was built to analyse the loss components in UTSi cells. Based on this model, an improved UTSi device with VOC of 714 mV, JSC of 37.6 mA/cm2, FF of 82.6% and efficiency of 22.2% has been predicted.