Large‐Area Boron‐Doped 1.6 Ω cm p‐Type Czochralski Silicon Heterojunction Solar Cells with a Stable Open‐Circuit Voltage of 736 mV and Efficiency of 22.0%

Herein, large‐area defect‐engineered p‐type silicon heterojunction (SHJ) solar cells using standard 1.6 Ω cm commercial‐grade boron‐doped Czochralski (Cz) silicon wafers are fabricated. It is demonstrated that despite achieving an open‐circuit voltage of 735 mV with an efficiency of 21.6% for gettered samples, without appropriate treatment, the cells are heavily susceptible to boron–oxygen‐related light‐induced degradation (LID), with the effective lifetime at maximum power point decreasing to 13 μs. This degradation results in a loss of efficiency of more than 3.1%_abs (14.3%_rel) after 48 h of light soaking. However, the addition of an advanced hydrogenation postcell fabrication process increases the efficiency by 0.2%_abs to 21.8%, and dramatically reduces susceptibility of LID, decreasing the extent of degradation to 0.2%_abs (0.9%_rel). A peak stable independently measured efficiency of 22.0% with an open‐circuit voltage (V_OC) of 736 mV is achieved with the addition of a dedicated high‐temperature prefabrication hydrogenation. These results indicate that p‐type Cz wafers can be used to fabricate stable, next‐generation high‐efficiency solar cells using silicon heterojunctions or other passivated contact architectures requiring V_OCS well above 700 mV.