Browsing by Author "Yildiz, Burak"

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Effect of Direct Linkage of Pyrazole Carboxylic Acid Acceptor/Anchoring Group on the Photovoltaic Performance for Phthalocyanine-Sensitized Solar Cells
(Elsevier Sci Ltd, 2022) Yildiz, Burak; Ahmetali, Erem; Arslan, Baris Seckin; Menges, Nurettin; Nebioglu, Mehmet; Sisman, Ilkay; Sener, M. Kasim
An unsymmetrical zinc phthalocyanine dye (PCA-ZnPc-4) containing six electron donating hexylsulfanyl groups and a pyrazole-3-carboxylic acid anchoring group which is directly linked to the macrocycle was synthesized to evaluate the photophysical, electrochemical, and theoretical characteristics as well as photovoltaic properties. Previously studied dye PCA-ZnPc-2 , which contains the same electron donating groups and pyrazole-3-carboxylic acid anchoring group with the bridging oxygen atom, was used as a reference dye. The optimized dye-sensitized solar cell (DSSC) based on PCA-ZnPc-4 exhibited an impressive power conversion efficiency of 2.52% (J(SC) = 6.53 mA cm(-2) , V-OC = 0.584 V, FF = 0.66), exceeding that of the DSSC based on PCA-ZnPc-2 (1.86%) under the same conditions. The better photovoltaic performance of PCA-ZnPc-4 is mainly due to its conjugated anchoring group, leading to efficient electron injection. This work demonstrates that the anchoring groups attached to the macrocycle without oxygen linker may enhance the photovoltaic performance of the phthalocyanine-sensitized solar cells.
Non-Aggregating Zinc Phthalocyanine Sensitizer With Bulky Diphenylphenoxy Donor Groups and Pyrazole-3 Acid Anchoring Group for Coadsorbent-Free Dye-Sensitized Solar Cells
(Pergamon-elsevier Science Ltd, 2021) Yildiz, Burak; Arslan, Baris Seckin; Guzel, Emre; Nebioglu, Mehmet; Menges, Nurettin; Sisman, Ilkay; Sener, M. Kasim
A novel unsymmetrical zinc phthalocyanine complex (PCA-ZnPc-3) containing six 2,6-diphenylphenoxy donor groups and pyrazole-3-carboxylic acid anchoring group has been synthesized and used as a sensitizer for dye sensitized solar cells (DSSCs). The optical, electrochemical and photovoltaic characteristics were evaluated and compared with the dyes containing the same anchoring group and tert-butyl (PCA-ZnPc-1) or hexylsulfanyl (PCA-ZnPc-2) donor groups, developed by our group. The DSSC with PCA-ZnPc-3 exhibited a higher power conversion efficiency (PCE) of 2.04% as compared to that of PCA-ZnPc-1 (PCE = 1.74%) and PCA-ZnPc-2 (PCE = 1.89%). This enhancement in efficiency may be ascribed to the less dye aggregation and appropriate dye coverage. These results suggest that the incorporation of 2,6-diphenylphenoxy into pyrazole-3-carboxylic acid based zinc phthalocyanine sensitizers can improve photovoltaic performance of DSSCs.
Pyrazole-3 Acid as a New Anchoring Group for Phthalocyanine-Sensitized Solar Cells
(Pergamon-elsevier Science Ltd, 2018) Yildiz, Burak; Guzel, Emre; Menges, Nurettin; Sisman, Ilkay; Sener, M. Kasim
We have designed and synthesized an unsymmetrical zinc phthalocyanine (PCA-ZnPc-1) bearing an electron-withdrawing pyrazole-3-carboxylic acid anchoring group and three electron-donating tert-butyl groups as a sensitizer for dye-sensitized solar cells (DSSCs). PCA-ZnPc-1 sensitized solar cell showed a modest power conversion efficiency (1.74%), which may suffer from the flexible and non-conjugated oxygen linker on the sensitizer. However, the obtained efficiency is found to be three to four times higher than that of the unsymmetrical ones bearing only carboxylic acid due to the combination of pyrazole and carboxylic acid moieties within the same anchoring group, which enhances the binding of the dye on the TiO2 surface and results in an increase of electron injection efficiency. Therefore, the pyrazole-3-carboxylic acid is a promising anchoring group for developing new phthalocyanines to build efficient DSSCs.