özlem arıer - Academia.edu (original) (raw)

Papers by özlem arıer

Journal of Alloys and Compounds, 2014

Nanotowers and interconnected nanowires of SnO 2 have been successfully synthesized using a simpl... more Nanotowers and interconnected nanowires of SnO 2 have been successfully synthesized using a simple carbothermal reduction method by heating mixtures of SnO 2 , graphite and Ag powders at 1050°C. Field emission scanning electron microscopy (FESEM) studies revealed that the synthesized nanotowers consist of layer-by-layer stacked SnO 2 nanosheets of average thickness 100 nm. At higher Ag concentration, interconnected nanowires of SnO 2 have been obtained. The formation of SnO 2 nanotowers involves vapor-solid growth, while the interconnected SnO 2 nanowires were formed by vapor-liquid-solid growth mediated by Ag 3 Sn liquid nanodroplets. Photoluminescence studies on SnO 2 nanotowers revealed intense peaks at 365 and 396 nm and a very weak broad band around 545 nm. The synthesized SnO 2 nanotowers and interconnected SnO 2 nanowires have potential applications as functional blocks in future nanodevices.

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011Thesis (PhD) -- İstan... more Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2011Bu çalışmadaki amaç öncelikle nano parçacıkların boyutlarını kontrol parametrelerini belirlemek ve farklı boyutlarda nanoparçacıklardan oluşan sollerden nano brukit ince filmler elde edebilmek ve elde ettiğimiz bu filmlerin yapısal ve optik özelliklerini ortaya koyabilmektir. Bu çalışmada, ayrıca sol-jel döndürerek kaplama tekniği ile TiO2-SiO2 ve TiO2-Al2O3 nano kompozit filmler ile karbon nanotüp katkılı nano brukit TiO2 filmlerin, yapısal ve optik parametrelerinin, üretim parametrelerine bağlılığı incelenmiştir. TiO2 filmlerinde su:asit hacim oranı ve ısıl işlem sıcaklığı gibi üretim parametrelerinin değişiminin, nano brukit TiO2 filmlerinin parçacık boyutları üzerindeki etkisi belirlendi. Böylece üretim parametreleriyle yapılan optimizasyonla nano parçacık içeren filmlerin parçacık boyutunun kontrolü sağlanmıştır. Nan...

Fen Bilimleri Enstitüsü, Jan 11, 2012

Sakarya University Journal of Science, 2020

Calculation of spectral transmittance and reflectance values of a multilayer coating need to be k... more Calculation of spectral transmittance and reflectance values of a multilayer coating need to be known the spectral refractive index and the extinction coefficient values. In order to calculate the spectral optical indices a software was developed. It uses the spectrophotometric transmittance and reflectance values of single layer coatings, each coated only with the material in question, and the thicknesses of these layers. Considering the effective functions it contains, the software was written in the Matlab programming environment.

Süleyman Demirel Üniversitesi Fen Bilimleri Enstitüsü Dergisi, 2017

Bu çalışmada, sol-jel döndürerek kaplama tekniği kullanılarak ITO cam altlıklar üzerine hazırlanm... more Bu çalışmada, sol-jel döndürerek kaplama tekniği kullanılarak ITO cam altlıklar üzerine hazırlanmış nano yapılı WO3 filmlerin yapısal, elektrokromik ve optik özellikleri, üretim parametrelerine bağlı olarak incelenmiştir. WO3 solünde, H2O:WO3 oranı değiştirilerek farklı parçacık boyutları içeren soller elde edilmiştir. Üretilen sollerden döndürerek kaplama yöntemi ile 2000 dev/dk hızda filmler hazırlanmıştır. Tüm filmlere 1.5 saat süreyle 300, 325, 350 ve 375 0 C'lerde ısıl işlem uygulanarak filmlerin yapısal ve optik özellikleri incelenmiştir. Parçacık boyutlarının H2O:WO3 oranı ve ısıl işlem sıcaklık değerlerinin artmasıyla artış gösterdiği atomik kuvvet mikroskopu (AFM) ve taramalı elektron mikroskopu (SEM) ile belirlenmiştir. X-ışını kırınımı (XRD) analizi sonucunda, filmlerin monoklinik faz yapısında olduğu gözlenmiş olup parçacıkların büyümesi için gerekli aktivasyon enerjisi 22.17 kJ /mol olarak hesaplanmıştır. Filmlerin yapısal ve morfolojik özelliklerinin yanı sıra elektrokimyasal ve optik özellikleri de incelenmiş, bu özellikler potentiostat ve uv-vis spektrofotometre kullanılarak karakterize edilmiştir.

Surface Review and Letters, 2019

In the present work, multi-walled carbon nanotube (MWCNT)-doped TiO2 nanocomposite films were syn... more In the present work, multi-walled carbon nanotube (MWCNT)-doped TiO2 nanocomposite films were synthesized by sol–gel method. The influence of nanotube concentration on the structural, electrical and optical properties of the films was investigated. The beneficial effects of the addition of carbon nanotubes into a TiO2 film and titania-coated MWCNTs have much in common. On the other hand, this work contributes to the previous studies in terms of the optical and electrical properties of MWCNT. For this reason, MWCNT/rare brookite-phased TiO2 matrix as simple sol–gel deposited composite films were investigated in our study. The XRD studies showed that the composite film has a brookite crystal structure at the annealing temperature of 450∘C. According to the surface morphology investigations, SEM image of nanocomposite film shows that composite film has a granular and rod-like structure. The absorbance measurements of the films were carried out by the UV–Vis spectrophotometer to investi...

Optik, 2017

In this study, the solution which includes TiO2 quantum dots (QDs) was mixed with the multiwall c... more In this study, the solution which includes TiO2 quantum dots (QDs) was mixed with the multiwall carbon nanotubes (MWCNTs) to prepare MWCNT-TiO2 QDs composite films. The effect of microstructures on the structural and optical properties of MWCNT-TiO2 QDs composite films was evaluated. The activation energy for crystallite growth of TiO2 QDs which are produced in brookite phases was calculated as 20.3 kJ/mol. The properties of MWCNT-TiO2 QDs composite films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and ultraviolet-visible absorption spectroscopy (UV-vis).

Surface and Coatings Technology, 2016

Abstract In the present work, pure phase vanadium oxide VO2 nanoparticled films were synthesized ... more Abstract In the present work, pure phase vanadium oxide VO2 nanoparticled films were synthesized using acetate based sol–gel precursors. The effect of the water: Vanadyl acetylacetonate ratio on electrochemical and structural properties of nanostructured vanadium oxide films was examined. The X-ray diffraction studies indicated that very strong crystallization of the VO2 monoclinic phase occurred for the as-deposited films at the annealing temperature of 500 °C. According to the atomic force microscopy and scanning electron microscopy measurements, the size and morphology of the granular structured film depend on the water: Vanadyl acetylacetonate ratio. I-V curve spectra were used to compute several characteristics of the films coated on indium tin oxide substrates such as the optical density, color efficiency and diffusion coefficient. Even though water: Vanadyl acetylacetonate ratio of 0.1 is expected to give the highest color efficiency value (33 cm2/C), higher diffusion coefficient (3.15 × 10− 12 cm2/s) is observed in the ratio of 0.01. As a result, the correlation between the ratios and electrochromic properties of the films was established.

Optik, 2016

Al doped ZnO (AZO) nano-composite films were synthesized on glass substrates with the sol-gel spi... more Al doped ZnO (AZO) nano-composite films were synthesized on glass substrates with the sol-gel spincoating method at the room temperature. The activation energy of AZO nano-composite films was calculated to be 49 kJ/mol for the particles growth. The electrical, structural and optical properties of AZO films were determined by changing ZnO:water and ZnO:Al ratios. ZnO:water and ZnO:Al ratios play an important role in controlling the electrical conductivity of the AZO nano-composite films. The optimum doping ratio of Al was found to be 2% in terms of the lowest resistivity, and above 2% Al-doping concentration, the surface resistivity of AZO nano-composite films starts to increase. The optical highest transmittance of the films of 86% in visible region, and low surface resistivity of 70 /ᮀ can be obtained for the optimum doping ratio of Al.

Materials Science in Semiconductor Processing, 2014

In this work, the ZnO were fabricated with the sol-gel spin coating method, and the effects of th... more In this work, the ZnO were fabricated with the sol-gel spin coating method, and the effects of the Dea:water ratios on the properties of the as-prepared ZnO thin films were determined by using a X-ray diffractometer, transmission electron microscope, scanning electron microscope, atomic force microscope, ultraviolet-visible spectrophotometer, and spectrophotometer. Experimental results indicated that the Dea:water ratio affected the structural and optical properties of the ZnO films considerably. The activation energy for the particle growth of ZnO nanofilms and the effects of the Dea:water ratios on the band gap values of the ZnO films were investigated. The film has an activation energy of 26.3 kJ/ mol, and optical band gap of 3.27-3.31 eV is proportional to the Dea:water ratio.

Surface and Coatings Technology, 2011

... Lett. 62 (2008) 361 364. [36] Challa SSR Kumar, in: Challa SSR Kumar (Ed.), Nanomaterials: To... more ... Lett. 62 (2008) 361 364. [36] Challa SSR Kumar, in: Challa SSR Kumar (Ed.), Nanomaterials: Toxicity, Health and Environmental Issues, Wiley-VCH, Weinheim, 2006, pp. 220-221. ... [40] Y. Djaoued, M. Thibodeau, J. Robichaud, S. Balaji, S. Priya, N. Tchoukanova, SS Bates ...

Composites Part B: Engineering, 2014

ABSTRACT In this work, TiO2–Al2O3 nano-composite films were deposited on glass substrates by the ... more ABSTRACT In this work, TiO2–Al2O3 nano-composite films were deposited on glass substrates by the sol gel method. The structural and optical properties of TiO2–Al2O3 nano composite films were characterized for different Al2O3:TiO2 volume ratio in TiO2–Al2O3 solution. The crystal size of TiO2 nanoparticles in TiO2–Al2O3 nano-composite films was determined for the different Al2O3:TiO2 volume ratios. Band gap energy values of the films were controlled by changing Al2O3:TiO2 ratios. The properties of TiO2–Al2O3 nano-composite films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), spectrophotometer (Perkin–Elmer), and Fourier transform infrared spectroscopy (FTIR). SEM results showed flower-like TiO2–Al2O3 nano-composite films.

Journal of Alloys and Compounds, 2011

ABSTRACT In this study, pure nanobrookite TiO2 thin films were successfully deposited on glass su... more ABSTRACT In this study, pure nanobrookite TiO2 thin films were successfully deposited on glass substrates with the spin-coating method using titanium butoxide and acetic acid. The particle size of TiO2 films was controlled by the water:AcAc volume ratio. This study shows that it is possible to obtain single oriented pure brookite films. The structural and optical properties of the nanobrookite TiO2 thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), spectrophotometer (NKD), and Fourier transform infrared spectrometer (FTIR).