Development of gel polymer electrolytes for application in quantum dot-sensitized solar cells

A methylcellulose–polysulfide gel polymer electrolyte has been prepared for application in quantum dot-sensitized solar cells (QDSSCs) having the configuration FTO/TiO2/CdS/ZnS/SiO2/electrolyte/Pt(cathode). The electrolyte with the composition of 30.66 wt.% methylcellulose, 67.44 wt.% Na2S, and 1.90 wt.% sulfur exhibits the highest conductivity of 0.183 S cm−1 with the lowest activation energy of 6.14 kJ mol−1. CdS quantum dot sensitizers have been deposited on TiO2 film via the successive ionic layer absorption and reaction (SILAR) method. The QDSSC fabricated using the highest conducting electrolyte and CdS QD prepared with five SILAR cycles exhibits a power conversion efficiency (PCE) of 0.78%. After deposition of zinc sulfide (ZnS) and silicon dioxide SiO2 passivation layers, the PCE of the QDSSC with photoanode arrangement of TiO2/CdS(5)/ZnS(2)/SiO2 increased to 1.42%, an improvement in performance by 82%.