The electrical properties of high performance multicrystalline silicon and mono-like silicon: Material limitations and cell potential

Abstract

We compare the electrical properties of p-type and n-type industrially grown High Performance (HP) multicrystalline silicon (mc-Si) and mono-like silicon. The materials are characterised in terms of their bulk lifetimes, their implied open circuit voltages, and the density and recombination velocity of recombination active grain boundaries and dislocation clusters within the materials. Quokka3 is applied to simulate the cell performance potential of the studied materials, and quantify the corresponding efficiency loss due to different recombination mechanisms occurring in the bulk. Our results show that bulk recombination causes a noticeable efficiency loss in high efficiency cast-grown silicon solar cells, varying from 0.1% to 3.1% absolute in the simulated devices, depending on the materials and also the ingot position of the wafers. The performance of p-type HP mc-Si is affected by both recombination at extended crystal defects and in the intra-grain regions. N-type HP mc-Si shows a slight advantage over p-type HP mc-Si in the intra-grain regions. The advantage of p-type mono-like Si over p-type mc-Si mainly comes from optical gains due to alkaline texturing, but the material exhibits large performance variations along the ingot of up to 2.4% absolute. N-type mono-like Si shows the most promising material properties, featuring less performance variation along the ingot than p-type mono-like Si, and the highest efficiency potential among the four studied materials.