Photonics / Fotonik
Permanent URI for this collectionhttps://hdl.handle.net/11147/2590
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Article Citation - WoS: 4Citation - Scopus: 4A 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.Article Citation - WoS: 8Citation - Scopus: 9Tuning 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, CananThree 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: 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 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, CananSolid 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: 16Citation - Scopus: 16Silylethynyl substitution for preventing aggregate formation in perylene diimides(American Chemical Society, 2021) Aksoy, Erkan; Danos, Andrew; Li, Chunyong; Monkman, Andrew P.; Varlıklı, CananEthynylene-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: 2Citation - Scopus: 31-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, SerdarImpurities 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: 6Citation - Scopus: 7Perylene Based Solution Processed Single Layer Woled With Adjustable Cct and Cri(MDPI, 2021) Bozkuş, Volkan; Aksoy, Erkan; Varlıklı, CananIn 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: 3Citation - Scopus: 4Soluble 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, CananNew 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).Article Citation - WoS: 5Citation - Scopus: 6Contribution of O-2 Plasma Treatment and Amine Modified Gos on Film Properties of Conductive Pedot:pss: Application in Indium Tin Oxide Free Solution Processed Blue Oled(Elsevier, 2019) Diker, Halide; Yeşil, Fatih; Varlıklı, CananPrimary (n-propyl amine, n-PRYLA), secondary (dipropyl amine, DPRYLA) and alcohol (propanol amine, PRPOHA) amine derivatives were used as amine sources in graphene oxide (GO) modification and obtained samples were named as nPRYLA-GO, DPRYLA-GO and PRPOHA-GO, respectively. Modified graphene oxide (mGO) derivatives were doped in poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PH1000) and O-2 plasma treatment (70W, 3 min) was applied on the spin casted films. PH1000:mGO films presented high optical transparency values (> 90%) and low resistivity (177-183 Q/sq). The roughness values were increased especially when the hydrophobic alkyl chain containing DPRYLA-GO and nPRYLA-GO were doped in PH1000. Prepared films were utilized as anode in solution processed blue organic light emitting diode. PH1000:PRPOHA-GO anode presented more than 30 nm of decrement in full with at half maximum and 1.6, 1.5 and 1.9 fold enhancements in current, power and external quantum efficiency values, compared to those of ITO anode, respectively.Article Citation - WoS: 28Citation - Scopus: 29Enhancing the Efficiency of Mixed Halide Mesoporous Perovskite Solar Cells by Introducing Amine Modified Graphene Oxide Buffer Layer(Elsevier, 2020) Şahin, Çiğdem; Diker, Halide; Sygkridou, Dimitra; Varlıklı, Canan; Stathatos, EliasIn this study, graphene oxide (GO) was synthesized via Tour method and then modified with two different amine sources that contained different branched alkyl chains. The GO and modified GOs (mGOs) with dihexylamine (DHA) and 2-ethylhexylamine (2EHA) as amine sources were used respectively as buffer layers in mixed halide mesoporous perovskite solar cells (PSCs) in order to examine whether they could improve their performance. GO and mGO samples were characterized by several techniques such as X-Ray Diffraction, X-Ray photoelectron spectroscopy (XPS), Raman analysis and thermal gravimetric analysis (TGA). The preparation of the CH3NH3PbI3-xClx perovskite solution was performed using standard Schlenk techniques under argon atmosphere to attain a homogeneous coverage of the perovskite film. The solar cells with the additional layer of mGO derivatives between perovskite and hole transporting layer showed an improved overall performance compared to the reference devices which was attributed to the enhanced charge carrier transport via the mGOs. In particular, 10% increase to the overall performance of the solar cells was monitored in devices where 2-ethylhexylamine (2EHA) modified GO was used, compared to standard cell without buffer layer. (C) 2019 Elsevier Ltd. All rights reserved.
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