Photonics / Fotonik

Permanent URI for this collectionhttps://hdl.handle.net/11147/2590

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Author: search.filters.author.Varlıklı, Canan

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  • Article
    Citation - WoS: 4
    Citation - Scopus: 4
    A Polymeric Copper Complex Based on a Pyrazole Derivative: Synthesis, Spectroscopic, X-Ray, and Biological Activity Studies
    (John Wiley and Sons Inc., 2024) Amin,M.A.; Diker,H.; Şahin,O.; Varlıklı, Canan; Soliman,A.A.
    A novel 1D coordination polymeric copper complex based on 4-(4′-nitrophenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one was prepared and characterized spectroscopically and thermally and via X-ray crystallographic investigation. The prepared copper-based structure was proved to have a 1D coordination polymer. X-ray studies showed that the polymeric copper complex was of octahedral geometry, the ligand acted as a bidentate ligand, and the nitro group attached to the ligand acted as a bridging group. The cytotoxic activities of the copper polymer were evaluated including against MCF-7 cells (breast cancer cell line), HepG-2 cells (hepatocellular carcinoma), and HCT-116 cells (colon cancer cell line). The morphological alterations of the complex treated cells were investigated using an inverted microscope. The cell cycle and apoptosis were evaluated and reported. The copper polymer exhibited the best antitumor activity against HepG-2 cells (35.22 ± 4.80 μM) while also causing a decline in the G2/M phase and a remarkable enhancement in the early apoptosis. © 2024 John Wiley & Sons, Ltd.
  • Research Project
    Fullerenlere Alternatif Yeni Asetil Köprülü Perilendiimidlerin Sentezi ve Akseptör Özelliklerinin Fotofiziksel Süreçlerle Araştırılması
    (2019) Varlıklı, Canan
    Organik güneş hücresi (OGH) nde elektrik üretimi, donörün ışığı soğruması ekziton oluşumu, ekziton difüzyonu, ayrışması ve elektron transfer süreçleri, elektron ve boşlukların katot ve anotta toplanması ile gerçekleşir. Literatürde birçok farklı elektron verici (D) ve alıcı (A) malzeme geliştirilmektedir. A malzemeleri içerisinde en sık kullanılanlardan birisi fulleren ve türevleridir. Bu türevlerin üretimi oldukça zor ve yüksek maliyetlidir. Bu sebeple, literatürde son 10 yıl da, fulleren içermeyen OGHne olan ilginin arttığı görülmektedir. Perilendiimidler (PDIler), görünür bölgedeki yüksek molar soğurma katsayıları ve elektron ilgileri ile dikkat çekmektedir. Ancak, PDIlerin genel organik çözgenlerdeki çözünürlükleri düşük, agregatlaşma eğilimleri fazladır. Güçlü perilen-perilen etkileşimleri film fazında mikroboyutlara ulaşabilecek kristalitler oluşturabilmektedir. Bu durum ise, ekziton haraketliliğini ve elektron ve boşlukların elektrotlarda toplanmasını olumsuz etkilemektedir. Bu proje kapsamında, izomerik saflıkta 1,6- ve 1,7- bis[(trifenil)(4-etinil-fenil)silan)- N,N′-di(2- etilhekzil)-perilen-3, 4, 9, 10-tetrakarboksilikasit diimid [1,6 ve 1,7-Di(TPhSi)APDI] sentezlenmiş, 1H ve 13C NMR ile karakterize edilmiştir. Saf izomerlerin absorpsiyon ve fotoluminesans özellikleri, indirgenme potansiyelleri, en yüksek enerjili elektron içeren moleküler orbital ve en düşük enerjili elektron içermeyen moleküler orbital enerji seviyeleri tespit edilmiştir. Referans olarak sentezlenen N,N′-di(2-etilhekzil)-perilen-3, 4, 9, 10- tetrakarboksilikasit diimid [PDI(2EH)] ve 1,6- ve 1,7-Di-TPhSiAPDI(2EH) in çözelti ve film fazı fotofiziksel özellikleri incelenmiştir. Yeni sentezlenen PDI türevlerinin ve ticari fulleren türevinin (PCBM), ticari bir donör olan poli[N-9'-heptadekanil-2,7-karbazol-alt-5,5-(4',7'-di-2- thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) ile çözelti ve film fazındaki etkileşimleri izlenerek, karşılaştırılmıştır. Filmlerin morjolojik özellikleri atomik kuvvet mikroskobu ölçümleri ile tespit edilmiştir. 1,7-Di-TPhSiAPDI(2EH) in agregatlaşma eğiliminin ve fotokararlılığının PDI(2EH) den düşük, soğurma dalga boyunun, elektron ilgisinin ve yaşam ömrünün PDI(2EH) den yüksek ve molar soğurma katsayısının PDI(2EH) ile aynı seviyede olduğu tespit edilmiştir. Bu özellikleri ile yeni molekülün uygun D malzeme kullanımı ile hazırlanacak OGH aygıtında, PDI(2EH) den yüksek verim vereceği düşünülmüştür.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 9
    Tuning the Colour of Solution Processed Perylene Tetraester Based Oleds From Yellowish-Green To Greenish-White: a Molecular Engineering Approach
    (Elsevier, 2023) Aksoy, Erkan; Bozkuş, Volkan; Varlıklı, Canan
    Three regioisomericaly pure 1,7-di-ethynyl bridged perylene-3,4,9,10-tetracarboxy tetrabutylesters functionalized with triisopropylsilyl-ethynylen (PTE1), phenyl-ethynylen (PTE2) and tetraphenylsilyl-ethynylen (PTE3) groups were synthesized. Photophysical, thermal, electrochemical, and solution processed electroluminescence (EL) behaviours were investigated in comparison with a basic perylene-3,4,9,10-tetracarboxy tetrabutylester (PTEref) structure. Stepwise π conjugation, allowed tuning the absorption and photoluminescence wavelengths of the PTEs without disturbing the photo, thermal and electrochemical stabilities; ≫10h, >250 °C, and >50 cycles, respectively. Electron mobility of PTE2 is measured to be more than 10-fold of the other PTE derivatives. Individual utilization of PTE derivatives as solid-state emitters in poly(N-vinylcarbazole) (PVK): 2-(4-Biphenylyl)-5-phenyl-1,3,4-oxadiazole (PBD) host matrix produced yellowish-green EL. Benefiting from higher electron mobiliy, PTE2 emitter presented the best device efficiency values with an EL maximum of 535 nm. Whereas dual doping of the synthesized PTEs with PTEref resulted in greenish-white light with increased stability. Although the emitting layer contained no red emitting component, optimization of the dual doping ratio of PTEref:PTE3 produced a colour rendering index value of 76 with Commission Internationale d'Eclairage coordinates of (0.29, 0.37).
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Influence of Cation Size and Polarity on Charge Transport in Ionic Liquid Based Electrolytes
    (Wiley, 2022) Aydın, Banu; Öner, Saliha; Zafer, Ceylan; Varlıklı, Canan
    Imidazolium-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
    The Effect of Imide Substituents on the Excited State Properties of Perylene Diimide Derivatives
    (Fırat Üniversitesi, 2022) Aksoy, Erkan; Danos, Andrew; Li, Chunyong; Monkman, Andrew; Varlıklı, Canan
    Solid state optical properties of fluorescent materials are important for many photonic devices such as organic light emitting diodes, frequency down-converters or luminescent solar concentrators. Perylene diimides (PDIs) represent one of the most popular organic semiconductors which find application in such photonic device applications. In this study, photophysical properties of two dibrominated PDI (DiBrPDIs), one of which contains a branched alkyl chain (2-ethylhexyl, 2-EH) and the other with an aromatic substituent (diisopropylphenyl, DIA) at the imide positions are comparatively studied. We report their absorption and photoluminescence, lifetime and photoluminescence quantum yield (PLQY), as well as photoinduced absorption properties (PIA) examined by fs-transient absorption spectroscopy. Having the same ? conjugated system, DiBrPDIDIA and DiBrPDI-2EH exhibited identical absorption and photoluminescence (PL) spectra in chloroform (?abs:527 nm and ?PL:552 nm). However, in film phase, DiBrPDI-DIA (?PL-DIA:596 nm; PLQY:73.4%) presented a shorter PL wavelength with a higher PLQY than that of DiBrPDI-2EH (?PL-2EH:649 nm; PLQY:36.7%). Bond lengths and core bending angles of PDI derivatives were calculated using Chem3D pro software. It was determined that the 2,6-diisopropylphenyl group in DiBrPDI(DIA) extends a distance of about 6.8 Å out from the imide positions, providing more effective steric protection from aggregation than the smaller 2EH group.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Photocatalytic Activity of Dye-Sensitized and Non-Sensitized Go-Tio2 Nanocomposites Under Simulated and Direct Sunlight
    (Wiley-Blackwell, 2022) İlhan, Hatice; Durmaz Çaycı, Gamze Belkis; Aksoy, Erkan; Diker, Halide; Varlıklı, Canan
    Graphene oxide (GO), amine-modified graphene oxide (mGO), and N-TiO2 composites were synthesized by low-temperature hydrothermal method and characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, FTIR, and BET analysis techniques. The films of synthesized TiO2, mGO:TiO2, N-TiO2, GO:TiO2, GO:N-TiO2, and commercially available P25 were prepared by doctor blade method. These films and their perylene-3,4,9,10-tetracarboxy tetrabutylester (PTE)-sensitized forms were employed as photocatalysts for the photodegradation of rhodamine-B (RhB) under Xe lamp and direct sunlight irradiations. Independent from the irradiation source, the photocatalytic order of the non-sensitized films were GO:N-TiO2 > GO:TiO2 > N-TiO2 > mGO:TiO2 > TiO2 > P25, but seven and 15 folds of increments were detected under direct sunlight irradiation. PTE-sensitized catalyst films exhibited more than two folds of increase in the photocatalytic rate constants compared to their non-sensitized counterparts under Xe lamp irradiation. Under direct sunlight irradiation no matter which photocatalyst was used, the photocatalytic activity of these films was enhanced seven folds. Reusability tests revealed no significant changes in the photocatalytic rate constants obtained with both the non-sensitized and sensitized films.
  • Article
    Citation - WoS: 16
    Citation - Scopus: 16
    Silylethynyl substitution for preventing aggregate formation in perylene diimides
    (American Chemical Society, 2021) Aksoy, Erkan; Danos, Andrew; Li, Chunyong; Monkman, Andrew P.; Varlıklı, Canan
    Ethynylene-bridged perylene diimides (PDIs) with different sized silane groups have been synthesized as a steric blocking group to prevent the formation of non-radiative trap sites, for example, strong H-aggregates and other dimers or excimers. Excited singlet-state exciton dynamics were investigated by time-resolved photoluminescence and ultrafast pump-probe transient absorption spectroscopy. The spectra of the excimer or dimer aggregates formed by the PDIs at high concentrations were also determined. Although the photophysical properties of the bare and shielded PDIs are identical at micromolar concentrations, more shielded PDI2 and PDI3 exhibited resistance to aggregation, retaining higher photoluminescence quantum yield even at 10 mM concentration and in neat films. The PDIs also exhibited high photostability (1 h of continuous excitation), as well as electrochemical stability (multiple cycles with cyclic voltammetry). Prevention of dimer/aggregate formation in this manner will extend the uses of PDIs to a variety of high concentration photonics and optoelectronic applications, such as organic light-emitting diodes, organic photovoltaics, and luminescent solar concentrators.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 3
    1-Octanol Is a Functional Impurity Modifying Particle Size and Photophysical Properties of Colloidal Zncdsse/Zns Nanocrystals
    (American Chemical Society, 2021) Sevim Ünlütürk, Seçil; Çağır, Ali; Varlıklı, Canan; Özçelik, Serdar
    Impurities in trioctylphophine (TOP) strongly affect nanocrystal synthesis. 1-Octanol among other contaminants in TOP is identified for the first time as a functional impurity by H-1 NMR. The deliberate addition of 1-octanol into trioctylphosphine reduced particle size and modified photophysical properties of ZnCdSSe/ZnS colloidal nanocrystals. NMR analysis furthermore revealed that 1-octanol is bonded to the nanocrystal surfaces. The ratio of integrals for the O-CH2 protons of 1-octanol, which is the lowest compared to the other ligands, suggests that 1-octanol plays a critical role to tune the particle size of nanocrystals. The increased amount of 1-octanol added into TOP reduces the particle size from 9.8 to 7.2 nm, causing a progressive blue shift in the UV-vis and PL spectra but leaving the alloy composition unaffected. The rate of nonradiative processes is enhanced with the amount of 1-octanol added into TOP, correlating with higher dislocation density observed in the nanocrystals. As a conclusion, 1-octanol is proposed as a functional impurity that varies particle size and nonradiative photophysical processes in the ZnCdSSe/ZnS colloidal nanocrystals.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 7
    Perylene Based Solution Processed Single Layer Woled With Adjustable Cct and Cri
    (MDPI, 2021) Bozkuş, Volkan; Aksoy, Erkan; Varlıklı, Canan
    In solution processed single layer white organic light emitting diode (WOLED) applications, the choice of host matrix and optimization of dopant levels represent two crucial parameters to consider. In this work, poly(N-vinylcarbazole) (PVK): 2-(4-Biphenylyl)-5-phenyl-1,3,4-oxadiazole (PBD) and PVK:1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl] phenylene (OXD-7) matrices are used as hosts for perylene based devices. PVK:PBD presented better compatibility and lower turn-on voltages compared to PVK:OXD-7. Benefiting from the exciplex emission observed at 630 nm, a color rendering index (CRI) value of 90 is reached with the device containing PVK:PBD as the host and 0.1 wt.% of an orange emitting perylene derivative, i.e., PDI. Introduction of the perylene based green emitter, i.e., PTE, in this emitting layer not only caused a fading in the exciplex emission, but also resulted in disappearance of the electroplex peak at 535 nm, which is detected between PVK:PBD and PTE in bare PTE containing devices. Full visible range coverage is achieved by optimizing the PDI:PTE ratio. WOLED containing PVK:PBD:0.06 wt.% PDI:0.03 wt.% PTE presented high CRI (>= 95) and adjustable correlated color temperatures (CCT, 3800 K-5100 K).
  • Article
    Citation - WoS: 3
    Citation - Scopus: 4
    Soluble Cytotoxic Ruthenium(ii) Complexes With 2-Hydrazinopyridine
    (Pleiades Publishing, 2019) Soliman, A. A.; Attaby, F. A.; Alajrawy, O., I; Majeed, S. R.; Şahin, C.; Varlıklı, Canan
    New water soluble Ru(II) binary complex [Ru(C5H7N3)(X)(H2O)(2)] with 2-hydrazinopyridine and its ternary complexes with X = dichloride, oxalate, malonate or pyrophosphate ligands have been synthesized. The complexes have been characterized using elemental analyses, mass, IR, and UV-Vis. spectroscopies, cyclic voltammetry, magnetic susceptibility, and thermal analysis. The complexes are diamagnetic and the electronic spectral data showed that peaks are due to low spin octahedral Ru(II) complexes. The optimized structures of the complexes 1-4 indicate distorted octahedral geometry with bond angles around the ruthenium atom ranged from 80.44 degrees to 99.64 degrees. The values of the electronic energies (-635 to -1145 a.u.), the highest occupied molecular orbital energies (-0.181 to 0.073 a.u.) and lowest unoccupied molecular orbital energies (-0.056 to 0.167 a.u.) indicate the stability of the complexes. The complexes are polarized as indicated from the dipole moment values (9.39-14.27 Debye). The complexes have noticeable cytotoxicity with IC50 (mu M): 0.011-0.062 (HepG-2), 0.015-0.080 (MCF-7), 0.015-0.116 (HCT-116), and PC-3 (0.034-0.125).