INVESTIGATION OF THE EFFECTS OF PLASTICIZERS IN A GEL ELECTROLYTE ON THE PHOTOVOLTAIC PERFORMANCE OF DYESENSITIZED SOLAR CELLS

Author (s) : M.Shanmugam, N.Janani, P.Vijayalakshmi

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Abstract :
Although liquid electrolyte-based dye-sensitized solar cells (DSCs) have shown higher photovoltaic performance in their class, they still suffer from some practical limitations such as solvent evaporation, leakage and sealing imperfections. These problems can be circumvented to a certain extent by replacing the liquid electrolyte using a gel polymer electrolyte. Even though, the use of gel polymer electrolytes sacrifices the performance of DSCs to some extent due to low ion mobility, they show cohesive nature of solids and diffusive nature of liquids while showing good stability in outdoor applications. This study focuses on a comparative study on the use of different plasticizers in polyacrylonitrile-based (PAN) gel polymer electrolyte. The plasticizers were dimethyl formaldehyde (DMF), dicholorometheane (DCM), dimethyl sulphoxide (DMSO), ethylene carbonate (EC) and propylene carbonate (PC). In addition, the use of tert-butylepridine (TBP) as a recombination suppressing agent was also investigated. The DSC device structure was FTO/TiO2/N 719 dye/gel electrolyte/lightly-platinized FTO counter electrode with I- /I3 - as the redox couple. The plasticizer combinations used in the gel electrolyte were EC/PC, EC/PC/TBP, DMF/DCM, DMF/DMSO, DMF/DMSO/TBP and their respective cell efficiencies were 5.00 %, 5.50 %, 3.84 %, 4.50 % and 4.70 %. It was observed that the JSC for the EC/PC/TBP system was the highest. This could be due to the formation of more cross-linking sites among C=O groups of the EC and PC and C≡N group of PAN leading to better diffusivity of I3 - . Comparison of the VOC values of 630 mV and 720 mV respectively of the EC/PC/TBP-based devices shows that the presences of TBP reduces the recombination due to TBP on spaces that are not covered by the dye molecules.

Keywords : conductivity, diffusivity, dye-sensitized solar cells, gel electrolytes, plasticizers

Conference Date : 13/11/2020

Pages : 68

Paper ID : 20068