Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 3Influence of Cation Size and Polarity on Charge Transport in Ionic Liquid Based Electrolytes(Wiley, 2022) Aydın, Banu; Öner, Saliha; Zafer, Ceylan; Varlıklı, CananImidazolium-based ionic liquids (ILs) with allyl and ether side chains were synthesized and characterized. Comprehensive structural and photoelectrochemical characterizations were performed, transport properties of ILs were also examined as electrolyte components in dye sensitized solar cells (DSSCs). The properties of synthesized materials and DSSC performances were compared with 1-propyl-3-methyl imidazolium iodide (PMII) and 1-allyl-3-ethyl imidazolium iodide (AEII) as reference ILs. Ionic conductivities, diffusion coefficients and charge transfer resistances of synthesized ionic liquids were investigated on DSSCs by Electrochemical Impedance Spectroscopy (EIS). The diffusion coefficient values of triiodide ions in different ionic liquid-based electrolytes were measured by the means of diffusion limited current density method and found to be 1.75×10−7 cm2 s−1 and 2.05×10−7 cm2 s−1 with corresponding photocurrent densities of 10.38 mAcm−2 and 12.13 mAcm−2 for the reference AEII and PMII based electrolytes, respectively. However, for the electrolytes of 1-(2-methoxyethyl)-3-allyl imidazolium iodide and 1-allyl-3-methyl imidazolium iodide ionic liquids, these values were found to be 0.86×10−7 cm2 s−1 and 0.57×10−7 cm2 s−1 with photocurrent densities of 9.53 mAcm−2 and 8.98 mAcm−2, respectively. Allyl and ether substituted imidazolium ILs exhibited promising results as potential alternative electrolyte materials for DSSCs.Article Citation - WoS: 4Citation - Scopus: 4Effects of Alkaline Earth Metal Additives on Methylammonium-Free Lead Halide Perovskite Thin Films and Solar Cells(Wiley, 2022) Yüce, Hürriyet; LaFollette, Diana K.; Demir, Mustafa Muammer; Perini, Carlo A.R.; Correa-Baena, Juan-PabloOrganic–inorganic lead halide perovskite solar cells are regarded as one of the most promising technologies for the next generation of photovoltaics due to their high power conversion efficiency (PCE) and simple solution manufacturing. Among the different compositions, the formamidinium lead iodide (FAPbI3) photoactive phase has a bandgap of 1.4 eV, which enables the corresponding higher PCEs according to the Shockley–Queisser limit. However, the photoactive crystal phase of FAPbI3 is not stable at room temperature. The most high-performing compositions to date have reduced this problem by incorporating the methylammonium (MA) cation into the FAPbI3 composition, although MA has poor stability at high temperatures and in humid environments, which can limit the lifetime of FAxMA1−xPbI3 films. CsxFA1−xPbI3 perovskites are also explored, but despite better stability they still lag in performance. Herein, the additive engineering of MA-free organic−inorganic lead halide perovskites using divalent cations Sr2+ and Ca2+to enhance the performances of CsxFA1−xPbI3 perovskite compositions is explored. It is revealed that the addition of up to 0.5% of Sr2+ and Ca2+ leads to improvements in morphology and reduction in microstrain. The structural improvements observed correlate with improved solar cell performances at low additive concentrations.