> 85% Indium Reduction for High-Efficiency Silicon Heterojunction Solar Cells with Aluminum-Doped Zinc Oxide Contacts

Aluminum-doped zinc oxide (AZO) has long been known as a promising low-cost alternative contact to conventional expensive indium-doped tin oxide (ITO) on silicon heterojunction (SHJ) solar cells. However, low fill factor (FF) of the AZO-based SHJ solar cell greatly limits the device performance as well as poses concerns about its commercial potential. Here, we present ITO/AZO/ITO stack as front contact on rear-junction SHJ cell, solving three challenges including sputter damage, bad contact and low conductivity simultaneously that are encountered on pure front AZO-based devices. Additionally, mechanism underlying the superior performance of ITO/AZO/ITO stack is unveiled by the analysis of phase, lifetime and electrical properties followed by Quokka3 simulation of vertical and lateral carrier transport. Then, successfully direct use of pure AZO at rear side of SHJ cell is demonstrated, though with a small increase of total series resistance (Rs). Finally, a champion efficiency of 23.8% with >85% indium reduction is achieved on M2+ size cell by using ITO/AZO/ITO at n-side and pure AZO at p-side, showing a high average efficiency (η ∼ 23.6%) close to that of totally ITO-based references (η ∼ 23.7%). These findings provide a promising way to fabricate low-indium and high-efficiency SHJ cells with commercial potential.