Dual-function smart electrolytes for novel design of dye-sensitized solar cells
thesisposted on 2017-03-02, 02:56 authored by Bhargava, Rishabh
Investigated derivatives of 5-mercaptotetrazoles as redox mediator in DSCs and corrosion inhibitors for metal charge collectors employed in large scale DSCs and observed that structural modifications in the 5-mercaptotetrazoles lead to differences in corrosion inhibition properties. Four wire sense measurement and cyclic voltammetry were utilized as characterization tools for characterizing the corrosion inhibition and suppression of recombination by 5-mercaptotetrazoles at the silver metal - electrolyte interface. The results were compared with standard iodine and cobalt based electrolytes. Rate of corrosion was two orders of magnitude lesser for the phenyl based 5-mercaptotetrazole derivative electrolyte compared to standard iodine and cobalt based electrolytes (0.2 nm/hr vs >3600 μm/hr respectively). STM measurements were carried out to characterize the coverage of the silver metal surface by the derivatives of 5-mercaptotetrazoles. Depending on the structure a dense monolayer could be achieved. Small and large area solar cells were fabricated utilizing the 5-mercaptotetrazoles as redox mediator and a proof of principle device achieved reasonable efficiency. Application of thiolate based electrolyte in development of ptype DSC and pn-DSC In addition, 5-methyl mercaptotetrazoles based electrolyte(Tph) was also investigated in p-type and pn-DSCs. We observed that applying these thiolate based electrolytes resulted in an improvement in VOC in p-DSCs compared to the devices based on iodide electrolytes, while maintaining similar JSC (5.3 mA/cm2) values. We also employed the Tph electrolyte in tandem DSCs with film thicknesses optimized for both the Tph and Iodine based electrolytes, we observed that the tandem cells based on the non-corrosive thiolate electrolyte exhibited similar conversion efficiencies (1.33%) to those based on iodide electrolytes (1.28 %). Our results reveal the great promise which the thiolate based electrolytes holds for future applications in p-DSCs and pn-DSCs.