A comparative study of the influence of N, N '-dialkyl vs. N, N '-diaryl-based electron donor ancillary ligands on photocurrent and photovoltage in dye-sensitized solar cells (DSSCs)

Ashraf, Saba
Yıldırım, Erol
Akhtar, Javeed
Siddiqi, Humaira M.
El-Shafei, Ahmed
In this study, we report the synthesis of a novel heteroleptic Ru(II)-sensitizer, (Ru(2,2'-bipyridine-4,4'dicarboxylic acid)-4,4'-bis(4-piperidin-1-yl) phenyl ethenyl)-(2,2'-bipyridine) (NCS)(2), denoted as SD-1; moreover, its photophysical, electrochemical, and photovoltaic performances were compared with those of N719 and K77-7 (N, N'-diaryl Ru-sensitizer, namely Ru(2,2'-bipyridine-4,4'-dicarboxylic-acid)4,4'- bis(2-(4-N, N'-diphenylaminophenyl) ethenyl)-2,2'-bipyridine (NCS) 2). The photovoltaic performance of SD-1 outperformed those of N-719 and K77-7, particularly in the red region, and the overall efficiency of SD-1 was 8.5% as compared to 8.0% of K77-7 and 7.7% of N719 under the same experimental device conditions. The superior light harvesting efficiency of SD-1 can be attributed to the strong electron donor sp3-nitrogen, which is attached to two sp3-carbons (dialkyl), whereas in the case of K77-7, all carbon atoms attached to the sp3-nitrogen are sp2, which decrease the electron density on the latter and minimize the electron-donating power of the ancillary ligand in K77-7. To gain a quantitative understanding of the electron density on nitrogen in SD-1 and K77-7, first-principle calculations using molecular and thermodynamic descriptors, such as frontier molecular orbitals, ground-state oxidation potential (GSOP), excited-state oxidation potential (ESOP), optical gap (E0-0), and charge distributions, were conducted in solution. In addition, for understanding the anchored structures of dyes on Ti24O48, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were utilized. Results of computational studies are in excellent agreement with the experimental results, which can be used as a screening tool for the design of more efficient molecular motifs for DSSCs.


A numerical taxonomic study of the genus Acantholimon Boiss Plumbaginaceae in Ankara Province Turkey
MUVAFFAK, Aslı; Doğan, Musa; Bilgin, Cemal Can (Laser Pages Publishing Ltd., 2001-01-01)
This study examines whether a satisfactory classification of Acantholimon Boiss. (Plumbaginaceae) species found in Ankara province (Turkey) can be obtained from phenctic clustering based on external vegetative and floral morphological characters of both herbarium and collected specimens, The study is on the following species: A. venustum Boiss., A, halophilium Bokhari., A. acerosum (Willd.) Boiss., A. kotschyi (Jaub. & Spach) Boiss., A. confertiflorum Bokhari., A. glumaceum (Jaub. & Spach) Boiss., A. casare...
A novel oxidative destruction of lignin and enzymatic digestibility of hazelnut shells
Uzuner, Sibel; Sharma-Shivappa, Ratna R.; Çekmecelioğlu, Deniz; Kolar, Praveen (2018-01-01)
This study investigated the effect of sequential oxidative (ozonolysis) pretreatment and enzymatic hydrolysis of hazelnut shells on production of fermentable sugars. Two factors (ozone concentration and pretreatment time), which were determined to be significant by the Box-Behnken response surface methodology, were further maximized for total lignin removal, solid recovery, and total reducing sugar yield via enzymatic hydrolysis of the pretreated biomass using full-factorial design. The ozonolysis was perfo...
A new method for synthesis of aziridine 2-phosphonates and their biological activities
Babiz, Hakan; Doğan, Özdemir; Department of Chemistry (2010)
A systematic study was carried out for the synthesis of aziridine 2-phosphonates by using two methods. First method is the classical Gabriel-Cromwell reaction and the second one is the modified version of Gabriel-Cromwell reaction which was developed in this thesis. In the first method, vinyl phosphonate was used as the starting material, then it was brominated to get 1,2-dibromoethyl phosphonate. HBr elimination from this compound, then reaction with different primary amines gave desired aziridinyl phospho...
A QSPR Study on the Physical Properties of Substituted Polypyrroles and Poly(paraphenylenes)
Yıldırım, Erol; Tuzun, Nurcan Senyurt; Yurtsever, Mine (2011-01-01)
In this study, a quantitative structure-property relationship (QSPR) study is carried out to estimate the physical properties of substituted polypyrrole (PPy) and polyparaphenylene (PPP). The effects of the substituted side-chains composed of epsilon-caprolactone, ethylene and styrene oligomers on the glass transition temperature, cohesive energy and dielectric constant of PPy and PPP are studied and the results are analyzed in terms of backbone structure, the type and the length of the side-chains. It is s...
A new strategy for the synthesis of pyridines from N-propargylic beta-enaminothiones
Kelgokmen, Yilmaz; Zora, Metin (Royal Society of Chemistry (RSC), 2019-03-07)
A new method for the synthesis of 2,4,5-trisubstituted pyridines from N-propargylic beta-enaminothiones is reported. beta-Enaminothiones were prepared by thionation of the corresponding beta-enaminones with Lawesson's reagent. When treated with diisopropylamine in DMF at room temperature, N-propargylic beta-enaminothiones yielded 2,4,5-trisubstituted pyridines in moderate to high yields, along with small amounts of 2-methylene-2,3-dihydro-1,4-thiazepines. The reaction was found to be general for a broad ran...
Citation Formats
S. Ashraf, E. Yıldırım, J. Akhtar, H. M. Siddiqi, and A. El-Shafei, “A comparative study of the influence of N, N ‘-dialkyl vs. N, N ’-diaryl-based electron donor ancillary ligands on photocurrent and photovoltage in dye-sensitized solar cells (DSSCs),” PHYSICAL CHEMISTRY CHEMICAL PHYSICS, pp. 20847–20860, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42669.