The effect of annealing temperature on the optical properties of a ruthenium complex thin film

The stability of the optical parameters of a ruthenium polypyridyl complex (Ru-PC K314) film under varying annealing temperatures between 278 K and 673 K was investigated. The ruthenium polypyridyl complex thin film was prepared on a quartz substrate by drop casting technique. The transmission of the film was recorded by using Ultraviolet/Visible/Near Infrared spectrophotometer and the optical band gap energy of the as-deposited film was determined around 2.20 eV. The optical parameters such as refractive index, extinction coefficient, and dielectric constant of the film were determined and the annealing effect on these parameters was investigated. The results show that Ru PC K314 film is quite stable up to 595 K, and the rate of the optical band gap energy change was found to be 5.23 × 10- 5 eV/K. Furthermore, the thermal analysis studies were carried out in the range 298-673 K. The Differential Thermal Analysis/Thermal Gravimmetry/Differantial Thermal Gravimmetry curves show that the decomposition is incomplete in the temperature range 298-673 K. Ru-PC K314 is thermally stable up to 387 K. The decomposition starts at 387 K with elimination of functional groups such as CO2, CO molecules and SO3H group was eliminated between 614 K and 666 K.State Planning Organization of Turkey (DPT2003K120390); Scientific and Technological Research Council of Turkey (TBAG-109T240

Organometalik fotosensörlerin sentezi ve foto-organik kimyasal çalışmalar

Bu çalışmada dört yeni tris heteroleptik rutenyum kompleksi (K20, K27, K28, K30) sentezlenmiş ve bunların fotosensör olarak boya temelli güneş pillerindeki performansları incelenmiştir. Komplekslerin karakterizasyonu UV-Vis, floresans, IR, TGA, NMR, elementel analiz ve döngüsel voltametri cihazlarıyla yapılırken boya temelli güneş pilleri içerisindeki elektron transfer dinamiklerinin incelenmesinde s ms çözünürlüklü zamana bağlı soğurma spektrometresi (Transient Absorption Spectroscopy) cihazı kullanılmıştır

Preparation of n-Type Silicon Coated Nano-Porous Membrane for Different Purposes

Homojen ve tekdüze gözenek çapına sahip nano gözenekli anodik aluminyum oksit kalıplar (AAO) kolay üretim tekniği açısından bir çok uygulama alanında geniş yer bulmuştur. AAO kalıplarının yüzeylerinin farklı fonsiyonel gruplar ile modifiye edilmesi, bu yapıların kararlılıklarını arttırdığı gibi uygulama alanlarını da genişletmektedir. Bu çalışmada, öncelikle düzenli nano kanallara sahip AAO membranlar anodizasyon tekniği ile hazırlanmıştır. Zira, ticari olarak kullanılan AAO membranlarda, düzenli olmayan nano kanal yapılarından dolayı uygulama açısından sorunlarla karşılaşılmaktadır. AAO nanogözenekli yapıların potansiyel uygulamalarının arttırılması için yapılar Plazma Destekli Kimyasal Buhar Biriktirme Yöntemi (PECVD) yardımıyla n‐tipi silikon ile kaplanmıştır. AAO membranların n‐tipi silikon ile kaplanma aşaması öncesinde anodizasyon işlemine maruz bırakılarak düzenli nano kanallar elde edilmiştir. Ardından, PECVD yöntemi ile AAO membran nano‐gözenek yüzeylerinin ve nano kanalların iç duvarlanının yaklaşık 40 nm kalınlığında bir n‐tipi silikon tabakası ile kaplanması sağlanmıştır. Bu membranlar AFM, SEM, EDX ve UV‐Görünür bölge absorpsiyon spektroskopisi ile karakterize edilmiştir. Elde edilen membranların 300‐700 nm arasında absorbsiyona sahip olması, mebranların n‐tipi silikon ile kaplandığını ayrıca teyit etmektedir. Elde edilen  şeffaf yapıdaki, n‐tipi silikon kaplı membranlar, başta fotovoltaik uygulamalar olmak üzere farklı amaçlara yönelik nano cihaz yapımında kullanılabilir.Nanoporous anodic aluminum oxide (AAO) with uniform and homogen pore diameters has been found wide range applications due to easy fabrication processes. Modification of AAO template surface by different functional groups increase the stability of these structures and also their potential utility in many applications. In this study, firstly the membranes which have regular nano‐channels was prepared by anodization technique. In fact, commercially available AAO membranes with non‐uniform nano‐ channel formations poses problems in terms of the applications. In order to improve the potential applications of AAO nanoporous structures, the surface of AAO membran was coated with an n‐type silicon by Plasma‐Enhanced Chemical Vapor Deposition (PECVD) Method. Before coating of AAO membranes with n‐type silicon, the regular nanochannels was obtained by exploring to n‐type anodization process. Then, the AAO nanoporous membrane surface and the inner wall were coated with n‐type silicon layer by PECVD method with thickness of ca. 40 nm. These membranes were characterized by AFM, SEM, EDX and UV‐Visible absorption spectroscopy. The resulting membranes exhibit the absorption between 300‐700 nm which confirms also that of n‐type membrane is coated with silicone. The obtained transparent n‐type silicon‐coated membranes can be used in the construction of nano‐devices for different purposes, including photovoltaic applications

Thermal analysis of cis-(dithiocyanato)(1,10-phenanthroline-5,6-dione)(4,4'-dicarboxy-2,2'-bipyridyl)ruthenium(II) photosensitizer

20th CTAS Annual Workshop and Exhibition CTAS -- MAY 12-13, 2010 -- Mississauga, CANADA --Thermal behavior of [cis-(dithiocyanato)(1,10-phenanthroline-5,6-dione)(4,4'-dicarboxy-2,2'-bipyridyl)ruthenium(II)], cis-[Ru(L1)(L2)(NCS)(2)] (where the ligands were L1 = 1,10-Phenanthroline-5,6-dione, L2 = 4,4'-dicarboxy-2,2'-bipyridyl) was investigated by DTA/TG/DTG measurements under inert atmosphere in the temperature range of 298-1473 K as well as by XRD analysis of the final product. After making detailed analysis and comparison of thermogravimetrical and MS measurements of ruthenium complex, the decomposition mechanism of that complex was suggested. The values of activation energy and reaction order of the thermal decompositions were calculated by Ozawa Non-isothermal Method for all decomposition stages. The calculated activation energies vary in between 32 and 49 kJ mol(-1).Scientific and Technical Research Council of Turkey (TUBITAK-BAYG)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)The authors would like to thank The Scientific and Technical Research Council of Turkey (TUBITAK-BAYG) for financial support. The authors thank to Prof. Dr. Nevzat Kulcu, Dr. Gokturk Avsar (from Mersin University, Turkey), and Dr. Selma Erat (ETH-Zurich, Switzerland) for their helpful discussions.WOS:0002905788000292-s2.0-7995937811

Systematic tuning the hydrodynamic diameter of uniformed fluorescent silica nanoparticles

We report a facile method for systematic tuning the hydrodynamic diameter of uniformed fluorescent silica particles in the size range from 12 to 465 nm. Dynamic light scattering and electron microscopy studies demonstrate that the hydrodynamic size distribution of the silica particles is uniform. We show that the initial amounts of ethanol and ammonia are essential to tune the size of these particles. The hydrodynamic diameter of such a particle increases as the amount of ammonia is increased. On the other hand, an increase in the amount of ethanol leads to the formation of smaller particles. Higher initial amount of ethanol yield an increase in the concentration of ethoxide ions and a decrease in the concentration of hydroxide ions. Such control over the concentration of hydroxide ion, which is responsible for the formation of siloxane bonds, causes a controlled-growth of the silica particles, resulting in precise tuning the hydrodynamic size. We confirm that a linear relationship exists between size and brightness of particles, demonstrating that the amount of dye molecules in such particles can be regulated by the presented method. We prove that the silica network provides protection for dye molecules encapsulated in particles against solvents, fluorescence quenchers, and unfavorable pH of environments. Moreover, the fluorescent silica particles with the size of 12, 50 and 250 nm were found to not be cytotoxic against the epithelial cell lines of MCF7 and PC3 even when the dosage levels up to 1.0 mg/ml and incubation periods up to 72 hours were applied

Biyotaklit Güneş Yakıt Cihazı Için Grafen Temelli Elektrotlar

Yirmi birinci yüzyılın en büyük sorunu artan dünya nüfusuyla beraber enerji ihtiyacında gözlenen artıstır. Bu ihtiyacı karsılamak amacıyla bilim dünyası çevre dostu, yenilenebilir alternatif enerji kaynakları arayısına yönelmistir. Günes enerjisi, günes ısıgını absorblayarak enerji dönüsümü saglayan yeni materyaller sayesinde süphesiz en çok ümit vadeden alternatif enerji kaynagı olarak karsımıza çıkmaktadır. Bu projenin amacı, hali hazırda günes enerjisinden yararlanarak yakıt elde edebilen cihazlara kıyasla daha üstün özelliklere sahip, yeni günes-yakıt cihazları için elektrodlar tasarlamaktır. Dolayısıyla elde edilecek olan bu elektrodun tasarımında elektrik iletimindeki benzersiz özellikleri ve düz bir yüzeye sahip olması nedeniyle tek katmanlı grafen yüzeyler kullanılmıstır. Grafen, Cyanidioschyzon merolae (C. Merolae) gibi dogal fotosentetik sistemlerden enerji transferinde neredeyse ideal bir elektrod gibi davranır. Bu hedeften yola çıkarak oldukça kararlı dogal fotosentetik kompleksler, fonksiyonel gruplar ile modifiye edilmis grafen kaplı elektrod yüzeyine spesifik olarak baglanmıstır. Proje kapsamında (i) daha önce kullanılan elektrodların aksine, ısık absorblayan fotosentetik kompleks yapıların yüzeye spesifik bir sekilde baglandıgı elektrodların eldesi, (ii) kontrollü bir oryantasyonun saglanmasıyla ısık absorpsiyonunun arttırılması ve bunun bir sonucu olarak foto dönüsüm verimliliginin yükselmesi, (iii) elde edilen elektrodun bir yıgın heteroeklem (BHJ) günes hücresi içindeki aktivitesinin incelenmesi, hedeflenmistir. Bu amaçla genis bir literatür arastırması yapılmıs, mevcut metodlara yeni yaklasımlar önerilmistir. Yüksek düzeyde disiplinlerarası özellikte olan bu proje çalısmasında, spektroskopiden moleküler biyolojiye, fotosentetik komplekslerin biokimyasından grafen elektrodların nanomühendisligine, fotosentetik yapılardaki plasmonik ve plasmon artısına dahası günes hücresi çalısmalarına kadar uzanan genis bir yelpazede deneyim sahibi olmayı sunmaktadır. Tüm bu disiplinlerin bir araya gelmesiyle fotoelektrokimyasal enerji dönüsümün gerçeklesebilmesi için gereken tecrübe ve uzmanlık temin edilmis olacak ve ?yesil? biyofotoelektrod yapım hedefi amaçlanmıstır. Proje içerigi, Bilim ve Teknoloji Yüksek Kurulu (BTYK) ve TÜBITAK tarafından Ulusal Bilim ve Teknoloji Politikaları kapsamında belirlenen Vizyon 2023 Strateji Belgesi'nde, öncelikli stratejik teknoloji alanları içinde, nanoteknoloji baslıklı kısmın, nanoelektronik, nanofotonik ve nanobiyoteknoloji alt baslıkları ile ilgili olup ülke öncelikleri arasındadır

An investigation of decomposition stages of a ruthenium polypridyl complex by non-isothermal methods

Symposium on Applications of Thermal Analysis and Calorimetry - Workshop and Exhibition (SATAC) 11th National Convention of Chemistry Teachers, India -- OCT 15-17, 2011 -- undefined, INDIA --Thermal properties of [cis-(dithiocyanato)(4,5-diazafluoren-9-one)(4,4'-dicarboxy-2,2'-bipyridyl)ruthenium(II)], [Ru(L-1)(L-2)(NCS)(2)] (where the ligands L-1 = 4,5-diazafluoren-9-one, L-2 = 4,4'-dicarboxy-2,2'-bipyridyl) have been investigated by DTA/TG/DTG measurements under inert atmosphere in the temperature range of 30-1155 degrees C. The mass spectroscopy technique has been used to identify the products during pyrolytic decomposition. The pyrolytic final products have been analyzed by X-ray powder diffraction technique. A decomposition mechanism has been also suggested for the cis-[Ru(L-1)(L-2)(NCS)(2)] complex based on the results of thermogravimetrical and mass analysis. The values of the activation energy, E* have been obtained by using model-free Kissenger-Akahira-Sunose and Flyn-Wall-Ozawa non-isothermal methods for all decomposition stages. Thirteen kinetic model equations have been tested for selecting the best reaction models. The best model equations have been determined as A2, A3, D1, and D2 which correspond to nucleation and growth mechanism for A2 and A3 and diffusion mechanism for D1 and D2. The optimized average values of E* are 31.35, 58.48, 120.85, and 120.56 kJ mol(-1) calculated by using the best model equations for four decomposition stages, respectively. Also, the average Arrhenius factor, A, has been obtained as 2.21, 2.61, 2.52, and 2.21 kJ mol(-1) using the best model equation for four decomposition stages, respectively. The Delta H*, Delta S*, and Delta G* functions have been calculated using the optimized values.WOS:0003105430000382-s2.0-8487091583

New approach for consideration of adsorption/desorption data

In this paper we proposed a new approach to modify the Langmuir model by considering nonlinear effects such as diffusion of water molecules in/out of an adsorbing film for humidity adsorption and desorption kinetics. The model was tested on the humidity adsorption and desorption data of a spin coated 50. nm thick Ruthenium polypridyl complex (Ru-PC K314) film, measured under relative humidity between 11% and 97% using by Quartz Crystal Microbalance (QCM) technique. © 2011 Elsevier B.V

Effects of Spinel Oxide Combustion Catalysts on the Combustion Behavior and Secondary Atomization Mechanism of Gasoline Droplets

Article; Early AccessThe catalytic activity of Mg-based spinel oxide nanoparticles (NPs) on the combustion behavior of gasoline and their effects on the atomization behavior were determined by droplet scale combustion experiments. MgFe2O4, MgCo2O4 and MgMnO3 spinel oxide NPs were produced by the sol-gel technique and doped into gasoline. The particles with the highest surface oxygen were MgCo2O4 and MgFe2O4 NPs, while the NPs with the largest surface area were MgCo2O4 NPs (517.8433 m(2)/g). The size of the flame envelope tends to shrink as the oxygen concentration of the particles rises, but an increase in their surface area tends to shorten ignition delay periods. MgFe2O4 NPs increased the flame temperature by 163 ; DEG;C compared to the pure gasoline. While MgFe2O4 and MgMnO3 NPs increased the extinction time of gasoline, MgCo2O4 NPs decreased the severe time by about 75% with the violent micro-explosions they created. In this study, we focused on the production of spinel oxide agents customized for combustion with improved catalytic activity, high flammability, and different component designs, and the results showed that these particles can reduce the soot formation of conventional hydrocarbons