A gel-state dye-sensitized hierarchically structured ZnO solar cell: Retention of power conversion efficiency and durability

• A gel-state ZnO-DSC was fabricated using dissoluble PS nanobeads on Pt electrode.
• Gel-state DSC showed almost identical efficiency to liquid electrolyte based DSC.
• Gel-state ZnO-DSC exhibited superior durability to liquid electrolyte based DSC.

A gel-state dye-sensitized hierarchically structured ZnO solar cell (ZnO-DSC) was fabricated by using dissoluble polystyrene (PS) nanobeads on Pt counter electrode as a gelator and ZnO nanocrystalline aggregates as a photo anode. Under an optimized acetonitrile/valeronitrile mixture solvent i.e. 85% v/v, the photovoltaic conversion efficiency (PCE) of the gel-state ZnO-DSC reached maximum up to 4.08%, comparable to a liquid electrolyte based DSC with value of 4.12% upon being measured under 1 sun illumination. The gel-state ZnO cell performance was also characterized and discussed by J–V data, IPCE, and EIS. The decay test results showed that the gel electrolyte based DSC possessed better photovoltaic stability than the liquid electrolyte based DSC in whether indoors or outdoors. Particularly, the PCE of the gel electrolyte based DSC decayed only 12% after 20 days under full sunlight outdoors, superior to the liquid electrolyte based DSC with an efficiency loss of 37%.