N-phthaloylchitosan based green polymer introduced into dye-sensitized solar cells

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A green polymer obtained from bio-waste was smeared to the dye-sensitized solar cells by experts in an experiment. Chitosan obtained from the crustaceans and insect’s chitin was transformed to generate the phthaloyichitosan electrolyte for the dye-synthesized solar cells with the efficacy of more than 7%.

Chitosan is a natural polymer obtained from chitin that can be identified in crabs, lobsters, and shrimps. Chitosan is non-toxic, odourless, biocompatible, bio-degradable and has huge mechanical strength. Such biopolymer has numerous potential applications like biomedical and pharmaceutical engineering, paper production, cement, food packaging, textile, film and finer formation and treatment of waste water.

Chitosan can be layered as polymer host in electrolytes, but it has degraded solubility and can only be dissolved in dilute acids. As a result, chitosan has been transformed through N-phthaloylation for improving its solubility. The substance can be dissolved in dimethyl-acetamide, dimethylflormamide, pyridine and dimethylsulfoxide. In this work, the gel electrolyte based on phthaloylchitosan has been crafted and applied in dye-based sensitized solar cells.

The dye-sensitized solar cells have the ability as a low cost greener substitute to the available silicon semiconductor based solar cells. The Si solar cells have now reached efficiencies of the order of 25% in the commercial and laboratory Si solar panels have potentials of the order of approximately 15 to 16%. Such panels are very costly due to the necessity of exceedingly pure crystalline substances for creating the solar cells. Also, harmful substances utilized during the generation of Si results in environmental pollution. The thin based on polycrystalline Si as well as other solar cells comparatively cost-effective but in fewer efficacies. The less costly amorphous Si based solar cells have the lesser life time of approximately 3 to 4 years only.

Comparatively, DSSC that was identified by Michael Gratzel of Switzerland in 1991 is much cost-effective as they do not need single crystal substances for their operation. A DSSC contains a cost-effective wide band semi-conductor like titanium di oxide sensitized with a dye absorb electrolyte and light containing a redox couple. The titanium di oxide is a harmless material extensively utilized in cosmetic industry. For DSS construction the substance is deposited on a guiding glass layered with a fine coating of platinum. The electrolyte is then placed between the working electrode containing the dye sensitized titanium di oxide and the cross-sectioned electrode.

The operating principle of the DSSC is simple as the photoanode possesses transparent conducting glass (TCG) onto the layer, which is layered with a titanium di oxide semiconductor and soaked in a ruthenium dye. The electrolyte gel that has been supplemented with mediators is sandwiched between the counter electrode and photoanode, usually platinum. The dye molecules captivate incident light and become energized.

This results in an electron being generated from each molecule of the dye. The electrons enter and percolate the semiconductor and leave behind the cell to the exterior circuit through the TCG and eventually reach the counter electrode. At that level, the intermediaries capture the electrons and transmit them to the dye molecules that have generated electrons and transmit them to the dye molecules that have released electrons after absorbing light.