Document Details
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Document Type |
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Thesis |
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Document Title |
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CYANINE-BASED PANCHROMATIC DYES FOR DYE-SENSITIZED SOLAR CELLS أصباغ السيانين متعددة الامتصاص للخلايا الشمسية للصبغة |
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Subject |
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Faculty of Science |
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Document Language |
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Arabic |
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Abstract |
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Global warming and rising energy needs have prompted a renewed interest in alternative energy technologies. In recent years, dye-sensitized solar cells (DSSCs) based on organic dyes have gained substantial interest due to their potentiality for inexpensive photovoltaic energy conversion. Among the variable organic photosensitizers, those based on cyanine (Cy) and hemicyanine (HCy) were notable for their stability and high molar absorption coefficients in the visible to near infrared spectral range. However, due to their characteristic narrow intramolecular charge transfer (ICT) absorption band, extensive studies still ongoing for advancing new strategies in order to increase their panchromatic responses, which is significantly valuable for achieving higher photovoltaic performances. Hence, this work focused on designing, synthesizing, and exploring novel cyanine and hemicyanine panchromatic dyes with advanced architectures, D---A, D-D--A, D--A-D--A. The structural designs involve the introduction of auxiliary donors, auxiliary acceptors and extended -spacers to enhance their panchromatic response and other optical properties as well as tunning their electrochemical properties. The synthesized structures were incorporated with some promising donors in the field of DSSC (carbazole, phenothiazine, phenoxazine, triphenylamine, and indole units), which were in conjugation with two different acceptor/anchoring groups, (noncarboxylated/ carboxylated indolium ion and cyanoacrylic acid). To avoid any susceptible aggregation and charge recombination, some of the units were subjected to alkylation with long alkyl chains beforehand. The desired molecular structures were achieved through multistep reactions utilizing some major reactions such as SN2 reaction, Vilsmeier-Haack reaction, bromination, borylation, Suzuki coupling reaction, and Knoevenagel condensation reaction. The newly synthesized dyes were characterized by FTIR, 1HNMR, 13CNMR, DEPT, HRMS, UV-Vis. and fluorescence spectroscopy and cyclic voltammetry. The photophysical and electrochemical data featured promising panchromatic responses with high molar extinction coefficients, high broadness covering the whole visible region, low optical bandgaps, and tuned HOMO/LUMO energy levels, which are a promising indication of their suitability as sensitizers in DSSCs. Hence, further theoretical, and experimental studies are under progress to assess their photovoltaic properties and evaluate their light harvesting and photocurrent conversion efficiencies. |
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Supervisor |
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Prof. Dr. Reda M. El-Shishtawy |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1445 AH
2023 AD |
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Added Date |
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Wednesday, October 25, 2023 |
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Researchers
| الهام نصيرالدين الهام نصيرالدين بي | Bifari, Elham Nasseraldeen | Researcher | Doctorate | |
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