Maximizing carrier extraction in hybrid back-contact silicon solar cells.

Abstract

Hybrid back-contact (BC) silicon solar cells^1-3 combine the strengths of tunnel oxide passivated contact (TOPCon)-derived^4-7 n-type contacts, silicon heterojunction (SHJ)-derived^8-12 p-type contacts and interdigitated back-contact (IBC)^13,14 device structures. Although high performance in the form of 27.8% efficiency has been demonstrated¹, the understanding of the fundamental advantages of the hybrid BC architecture over conventional BC cells (for example, eliminating front-surface metallization shading³) remains unexplored. Here we take advantage of the design flexibility of the hybrid BC architecture to use a multifunctional front layer for both light trapping and passivation. Meanwhile, we improved carrier collection and process compatibility of the rear carrier-selective contacts. We also show that the optimal crystalline silicon (c-Si) absorber thickness is increased to 160 μm, leading to a certified efficiency of 27.62% for industrially compatible c-Si solar cells.