Solution‐Processed PEDOT:PSS/p‐Si/ZnO Heterojunction Solar Cells

Abstract

With the introduction of the concept of dopant‐free carrier‐selective contact for c‐Si photovoltaics, Si‐based heterojunction solar cells can greatly reduce production costs by optimizing the manufacturing process while maintaining high power conversion efficiency. Compared with processes that rely on complex vacuum equipment, low‐temperature solution processing has many advantages over conventional silicon solar cells. However, research on low‐cost and high‐efficiency solar cells based on p‐type crystalline silicon is relatively rare. From the point of view regards energy band matching, the inorganic metal oxide semiconductor material ZnO is well suited for low‐cost solution method studies due to its easy preparation, very high transmittance in the visible spectrum, low cost, and suitable energy levels matching p‐Si. Herein, ZnO is spin coated on the back of p‐Si to form a heterojunction, together with spin coating of PEDOT:PSS on the front side as the hole transport layer and passivation layer, a PEDOT:PSS/p‐Si/ZnO‐structured p‐Si‐based backcontact hybrid solar cell is successfully fabricated at low temperature (≤135 °C) via solution process with a PCE of 9.77% (Voc = 0.56 V, Jsc = 25.99 mA cm−2, fill factor = 67.10%). This work provides a promising approach for fabricating high‐performance and low‐cost silicon‐based heterojunction solar cells.