Hybird Heterojunction and Photoelectrochemistry Solar Cell Based on Silicon and Graphene Woven Fabrics (GWFs)

Crystalline silicon based solar cells have drawn tremendous interest in the photovoltaic market. A facile route to obtain GWFs was reported lately by simply replacing copper with copper meshes substrate in chemical vapor deposition. In addition to its extraordinary electromechanical performance, GWFs also has an alternative application as transparent electrodes as well as graphene film in heterojunction solar cell with Si. Although its conductivity may be fade to graphene film, GWFs surely has better light transparency property because of its cross ribbon structures. This structure was also beneficial to embed other materials, such as liquid electrolyte and other conductive polymers for energy harvesting. Recently, solid state electrolyte has attracted a lot of attention due to its great potential in assembling of flexible nanodevices.

         In this paper, we proposed a hybrid heterojunction and photoelectrochemistry solar cell based on Si and GWFs. GWFs not only served as the transparent layer for charge collection and transport, but played an important role as p-type layer to form heterojunction with Si. In addition, particular configuration of woven fabrics with empty space between meshes facilitated the filling up of acidic solid state electrolyte. HNO₃ solid state electrolyte significantly boosted the efficiency by comprehensively improving the open circuit voltage, short circuit current density and fill factor by simply spin-coating on GWFs-Si solar cell. The role of HNO₃ solid state electrolyte was discussed in detail. Different models were designed to confirm the hybrid function existed in the solar cell and we can prove that heterojunction junction and photoelectrochemistry function worked synergistically. By accommodating the density of HNO₃ solid state electrolyte, the power conversion efficiency could reach up to 11.03%, which was really encouraging. Subsequent experiment convinced H₃PO₄solid state electrolyte also had positive effect to enhance power conversion efficiency. By adopting solid state electrolyte, we stood a chance to assemble flexible solar cells by precisely controlling the thickness of Si and maintain the cell efficiency at the same time, which extends the application area of GWFs-Si solar cell to flexible field.

Fig. (a) Optical image of the solar cell (b) schematic diagram of the solar cell