The interdigitated back-contact structure makes the efficiency of single-junction crystalline silicon (c-Si) solar cells approach the theoretical limit. However, the complexity of fabrication process hinder its large-scale commercial application. Here, we have developed a back-contact Si-based solar cell with dopant-free heterojunction by solution process. Nafion film was used as a dual functional layer of passivation and antireflection, PEDOT:PSS film as a hole transport layer, and patterned lithium acetate film as an electron transport layer. The efficiency of the prepared back-contact heterojunction solar cell is 15.4%, and the short-circuit current density is up to 36.6 mA/cm2.

The performance of organic‐inorganic hybrid solar cells (HSCs) can be improved by modifying the hole transport layer (HTL). Poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is the most active HTL material in organic‐inorganic HSCs and has been widely studied. Nevertheless, charge transfer in PEDOT:PSS is limited and inefficient due to the presence of the weak ionic conductor PSS. Moreover, the working function of the PEDOT:PSS film and the passivation of the PSS at the Si/PEDOT:PSS interface play a crucial role in carrier separation. The focus of this work is to explore a universal modification method to simultaneously achieve improved charge transport and interfacial passivation capability when using PEDOT:PSS as HTL. By combining bilayer design and simple solution posttreatment, the direct current conductivity (σdc) and work function of the HTL based on PEDOT:PSS are increased to 765 S cm−1 and 5.00 eV, respectively. The organic‐inorganic HSCs prepared using this approach achieve a photovoltaic conversion efficiency (PCE) of 12.33%, achieving a 16.54% improvement over untreated devices.

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.