Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV19)
DOI: https://doi.org/10.29363/nanoge.hopv.2020.117
Publication date: 6th February 2020
The chemical complexity of traditional Dye Sensitized Solar Cells (DSSCs) electrolyte requires the development of high selectivity and catalytic materials as counter electrode for the triiodide target molecule [1]. Molecular Imprinting Polymers (MIP) are a specific class of materials able to assure a high selectivity versus a dedicated target molecule in complex matrix and are therefore used in high performance sensors and chromatographic applications [2,3]. Moreover, these materials can be easily synthetized by low cost and environmentally friendly processes. In this work, an application of MIPs materials as counter-electrode in “Platinum free” Dye-Sensitized Solar Cells (DSSCs) was introduced to enhance the selectivity towards triiodide molecule (the target) contained in the electrolyte. The latter is commonly a complex matrix containing other than the target molecule other compounds used as additives and stabilizers that can compete with the triiodide reduction. Polypyrrole was used as “Non-Imprinted” (NIP) and “Imprinted” polymer (MIP) and was prepared by an electrochemical method. In order to demonstrate the positive effect of MIP on the catalytic activity at the counter electrode, two different template molecules were used: Glycine and L-Alanine (the first one with similar surface to the triiodide one and the second one with higher surface). The influence of different concentrations of Glycine template (25-50 and 100 mM) on the electrochemical and catalytic properties of PPy on triiodide reduction was studied both on 3-electrodes cell and symmetrical cells. Quasi-solid DSSCs (with polymeric electrolyte) with MIP-PPy based on the lowest Glycine concentration (25mM) produce the best results increasing the photovoltaic efficiency of the devices (close to 20%) as a consequence of the lowering charge transfer resistance (reduced to 50%). These results are mainly due to the MIP high selectivity on triiodide instead of the NIP system. This work open the possibility for the first time to apply MIP materials into energy systems based on DSSCs improving their properties.