Highly efficient silicon heterojunction solar cells with ZnO:Al transparent electrode and transition metal doped indium oxide interfacial layer

Indium consumption is the roadblock for terawatt-scale silicon heterojunction (SHJ) solar cells. Here, we report that M6 wafer scale SHJ cells reached an efficiency of 24.94% using room temperature DC sputtering deposited ZnO:Al (AZO) transparent electrode. Compared with indium tin oxide (ITO) standard cells, interfacial contact and smaller bandgap are observed to be the main factors that limit the AZO solar cell performance. By introducing a transition metal doped indium oxide (IMO) interfacial layer, significantly higher SHJ cell performance is achieved owing to better interface and AZO quality. With increasing IMO thickness, the conversion efficiency of SHJ cells surpasses that of the ITO reference cell when only about 50% of indium is consumed. The certified efficiency of the SHJ cells with stacked transparent electrodes reached 25.62%, which is one of the best results for low-indium SHJ cells. The present work provides a novel and practical solution to overcome the shortage of indium resources for terawatt-scale SHJ cells.