PVcomB

Silicon Heterojunction Solar Cells

Silicon heterojunction (SHJ) solar cells are made of silicon wafers using passivated contacts for both polarities based on i/n and i/p stacks of thin-film silicon alloys, such as amorphous silicon (a-Si:H), nanocrystalline silicon (nc-Si:H) or silicon oxide (nc-SiO_x:H). Due to a high silicon wafer quality and the excellent surface passivation SHJ solar cells reach very high conversion efficiencies with highest open circuit voltages >740 mV and low temperature coefficient <0.3 %/K. The lean cell process sequence of only four major process steps, all below <200°C processing temperature facilitate cost-effective production.

At PVcomB we operate a baseline for SHJ solar cells (Figure 1) currently reaching a certified efficiency of 24.6% (Figure 2). Processes and materials are developed up to a size of 166 x 166 mm² (M6), partially in cooperation with industry partners for:

• High-efficiency PV cells and modules
• Silicon heterojunction solar cells for application as bottom cell in high-efficiency multi-junctions, e.g. with perovskite top cells.
• Advanced silicon-based passivating contact layers for novel types of silicon-based solar cells, such as liquid-phase crystallized silicon (LPC-Si) solar cells on glass.
• Silicon heterojunction and thin-film silicon solar cells for hydrogen generation.
• All-rear-contacted (IBC) silicon heterojunction solar cells.

Fig. 1: Baseline process sequence and device structure for Silicon Heterojunction solar cells at PVcomB.