Impact of metal electrode work function of CH₃NH₃PbI₃/p-Si planar heterojunction perovskite solar cells

The use of p-type silicon (p-Si) as hole transport materials (HTM) has been suggested to enhance the stability of perovskite-based solar cell (PSC). We design and simulate the CH₃NH₃PbI₃/p-Si planar heterojunction perovskite solar cell and the power conversion efficiency exceeding 18%. In the solar cell, the metal electrode work function of perovskite solar cells is a decisive factor for built-in voltage (V_bi). The device simulation revealed that the V_bi and V_OC increases when rear electrode work function (ф_M−rear) decreasing from −4.3 eV to −4.7 eV, the V_bi almost saturate to the plateau and the performance is optimal when ф_M−rear = −4.8 to −5.2 eV. However, the work function of the front electrode (ф_M−front) also has a significant effect on the performance of p-Si perovskite solar cell. When ф_M−front decreasing from −3.4 to −4.0 eV, a higher performance can be obtained and the V_bi almost saturate to the plateau. The results showed the importance of the ф_M matching to maintain V_bi, which is useful guideline for the design of the p-Si perovskite solar cell.