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Nanotehnologija i nanomaterijali predstavljaju prekretnicu u modernoj znanosti. Njihovom primjenom postiže se neizmjeran tehnološki napredak. Zbog izvrsnih svojstava posebnu ulogu imaju nanomaterijali poput nanosrebra i grafena. Međutim, postupci njihove proizvodnje mogu biti vrlo komplicirani te izuzetno skupi. Cilj ovog rada je dobiti grafen i nanosrebro postupkom fotoredukcije. U tu svrhu korištena je intenzivna pulsirajuća svjetlost (Intense pulsed light, IPL) pomoću koje je provedena redukcija srebrova klorida i grafen oksida. Kao rezultat su dobivene nanočestice srebra te reducirani grafen oksid dispergiran u različitim sustavima kao što su voda, etanol, N,N-dimetilacetamid (DMAc), citratni pufer pH vrijednosti 10 te etanol uz dodatak polivinil butirala (PVB) kao stabilizatora. Zbog svoje jednostavnosti, brzine, ekološke prihvatljivosti i niske potrošnje energije fotoredukcija intenzivnom pulsirajućom svjetlosti je sve češće primjenjivana metoda dobivanja nanomaterijala. Učinkovitost redukcije praćena je UV/Vis spektrofotometrom, a rezultati su prikazani grafički. Reduciranost grafen oksida se očituje pomakom maksimuma apsorpcije sa vrijednosti od oko 230 nm do oko 260 nm. Analizom rezultata može se zaključiti da se fotonska redukcija grafen oksida može uspješno provesti u različitim disperznim sredstvima. Također, uspješno je provedena fotoredukcija srebrovog klorida, a prisutnost nanosrebra potvrđena je pojavom maksimuma apsorbancije pri valnoj duljini od 420 nm. Nanotechnology and nanomaterials represent a turning point in modern science. Their application leads to immense technological progress. Due to their excellent properties, nanomaterials such as nanosilver and graphene play a special role. However, their production processes can be very complicated and extremely expensive. The goal of this thesis is to obtain graphene and nanosilver by photoreduction. For this purpose, intense pulsed light (IPL) was used to reduce silver chloride and graphene oxide. As a result, silver nanoparticles and reduced graphene oxide were obtained dispersed in different solvents such as water, ethanol, N,N-dimethylacetamide (DMAc), citrate buffer with a pH value of 10, and ethanol with the addition of polyvinyl butyral (PVB) as a stabilizer. Due to its simplicity, promptitude, environmental suitability and low energy consumption, photoreduction with intense pulsed light is increasingly used as a production method of nanomaterials. The reduction efficiency was monitored with a UV/Vis spectrophotometer, and the results were presented graphically. The reduction of graphene oxide is manifested by the shift of the absorption maximum from a value of approximately 230 nm to 260 nm. Analyzing the results, it can be concluded that the photoreduction of graphene oxide can be successfully carried out in different dispersants. Also, the photoreduction of silver chloride was successfully performed, and the presence of nanosilver was confirmed by the appearance of an absorbance maximum at a wavelength of 420 nm.

The industrial realization of graphene has so far been limited by challenges related to the quality, reproducibility, and high process temperatures required to manufacture graphene on suitable substrates. We demonstrate that epitaxial graphene can be grown on transition metal treated 6H-SiC(0001) surfaces, with an onset of graphitization starting around $450-500^\circ\text{C}$. From the chemical reaction between SiC and thin films of Fe or Ru, $\text{sp}^{3}$ carbon is liberated from the SiC crystal and converted to $\text{sp}^{2}$ carbon at the surface. The quality of the graphene is demonstrated using angle-resolved photoemission spectroscopy and low-energy electron diffraction. Furthermore, the orientation and placement of the graphene layers relative to the SiC substrate is verified using angle-resolved absorption spectroscopy and energy-dependent photoelectron spectroscopy, respectively. With subsequent thermal treatments to higher temperatures, a steerable diffusion of the metal layers into the bulk SiC is achieved. The result is graphene supported on magnetic silicide or optionally, directly on semiconductor, at temperatures ideal for further large-scale processing into graphene based device structures., 10 pages, 4 figures, 51 references

U ovom završnom radu obrađena je tema razvoja i primjene nanostrukturiranih materijala. U uvodu je opisano porijeklo nanotehnologije. Opisan je povijesni razvoj nanotehnologije od početaka, točnije od 1959. godine do danas. Navedene su i objašnjene podjele i svojstva nekih nanostrukturiranih materijala. Nadalje su navedeni i objašnjeni primjeri primjene nanostrukturiranih materijala te njihova svojstva na polju elektrotehnike i medicine. Na kraju su elaborirani problemi koji stoje u daljnjem razvoju i primjeni nanostrukturiranih materijala. This final paper deals with the development and application of nanostructured materials. The origin of nanotechnology is described in the introduction. The historical development of nanotechnology from the beginning, more precisely from 1959 to the present, is described. The classification and properties of some nanostructured materials are outlined and explained. Furthermore, examples of the application of nanostructured materials and their properties in the field of electrical engineering and other fields are given and explained.

Fast ongoing research of graphene-based nanomaterials reveals that their exceptional properties could be utized for biomedical applications, especially in tissue engineering and drug delivery. Here, we summarized the results obtained on hydroxyapatite based biocomposite coatings produced by electrophoretic deposition on titanium substrate and reinforced by nanosized graphene, as potential candidates for hard tissue implants. Brzi razvoj istraživanja nanomaterijala koji sadrže grafen otkrio je da se njihova izuzetna svojstva mogu koristiti za biomedicinske primene, posebno u inženjerstvu tkiva i kao nosači lekova. U ovom radu su prikazani rezultati istraživanja biokompozitnih prevlaka na bazi hidroksiapatita koje su dobijene elektroforetskim taloženjem na titanskom supstratu i ojačane nanočestičnim grafenom, kao potencijalnih kandidata za implante koštanog tkiva.

2010 yılı nobel fizik ödülünün grafen hakkındaki ‘’Çığır açan deneyleri’’ dolayısıyla Hollandalı Andre Geim ve Rus kökenli İngiliz vatandaşı Konstantin Novoselov’a verilmesi dikkatleri ‘’mucize materyal’’ olarak da bilinen bu malzeme üzerine çekmiştir. Grafen tek atom inceliğinde olduğundan dolayı iki boyutlu kabul edilen, kovalent bağ ile bağlı karbon atomlarının altılı balpeteği örgüsünde kusursuzca dizilmesiyle oluşturduğu üstün özelliklere sahip bir nanomateryal olarak tanınmaktadır. Grafen yapısında karbon-karbon arası bağ uzunluğu 0,142 nm’dir. Grafen içindeki elektronlar oda sıcaklığında kütlesiz rölativistik parçaçıklar gibi davranır, bu sayede grafen kuantum boşluğu etkisi gibi kendine has özellikler sergiler. Grafenin temel üstün özellikleri geniş yüzey alanı (2630 m 2 g – 1) yüksek elektron mobilitesi (200000 cm2/(V s) yüksek ısıl iletkenliği (5000 Wm-1K-1) ve yüksek young modülü (~1100 Gpa) olarak sıralanabilir. Bu malzeme sahip olduğu üstün özellikler nedeniyle bir çok uygulama alanı bulmaktadır bunların başlıcaları transparan elektrotlar, alan etkili transistörler, sensörler, temiz enerji cihazları, nanokompozitler ve organik fotovoltaik cihazlar olarak sayılabilir. Bu çalışmada üstün özellikleri ile ön plana çıkan grafen nanomateryalinin üretim yöntemleri ele alınacaktır. Graphene attracted great attention, after Andre Geim and Konstantin Novoselov were awarded the Nobel prize (2010) in Physics because of their “groundbreaking experiments” on the “miracle material” graphene. Graphene is a two dimensional nanomaterial, which has superior properties, and a layer of covalently bound carbon atoms arranged in a perfect honeycomb (hexagonal) lattice. The carbon-carbon bond length of graphene is approximately 0.142 nm.The electrons on the structure of graphene acts as massless particles and therefore, it causes unique properties like quantum hall effect. Some main properties of graphene are large surface area (2630 m2 g-1), high electron mobility (200,000 cm2/(V s), high thermal conductivity (5000 Wm-1K-1) and high young modulus (~1,100 Gpa). Because of its superior properties, graphene found applications in many areas such as transparent conductors, clean energy devices, sensors, nanocomposites and organic photovoltaic devices. In this study the production methods of graphene will be discussed.

Yüksek Lisans Tezi, Geleceğin "mucize materyali" olarak adlandırılan grafen, balmumu yapısında dizilmiş sp2-bağlı karbon atomlarının oluşturmuş olduğu iki boyutlu tek tabakalı bir karbon temelli nanomateryal olup çok ince ve çok dayanıklı bir malzemedir. Grafen, geniş yüzey alanı, göstermiş olduğu mükemmel elektron transfer performansı, yüksek mekanik mukavemet ve oldukça yüksek termal iletkenlik gibi özelliklerinden dolayı fizik, kimya, biyoloji, biyoteknoloji, mühendislik, tıp ve özellikle nanoteknoloji alanlarında transistörlerden pillere, elektronik cihazlardan tekstil ürünlerine, ilaç geliştirme sistemlerinden sensörler alanına önemli bir yer tutmaya başlamıştır. Bu tez çalışmasında nanobilim ve nanoteknolojinin parlayan yıldızı olan grafen materyaline yakın özellik sergileyen grafen esaslı nanomateryalin (indirgenmiş grafen oksit) pratik ve ekonomik bir yöntem kullanılarak esnek ve şeffaf yüzeylere düzenli desenlenmesi gerçekleştirildi. Bu amaçla başlangıç maddesi olarak grafit kullanılarak kimyasal yükseltgenme metodu ile grafen oksit (GO) elde edildi. GO'nun yapısal karakterizasyonu Ultraviyole-Görünür bölge (UV˗Vis) spektroskopisi, Fourier dönüşümlü kızılötesi (FTIR) spektroskopisi ve Raman spektroskopi teknikleri ile, morfolojik karakterizasyonu taramalı elektron mikroskopu (SEM), geçirimli elektron mikroskopu (TEM) ve atomik kuvvet mikroskopu (AFM) teknikleri ile gerçekleştirildi. Hazırlanan grafen oksit dispersiyonu katı mürekkep yazdırma cihazı ile desenlenmiş membran yüzeyine vakum filtrasyonu ile filtre edildi. GO tabaka kalınlığının kontrolünü sağlayan bu sistem sonrasında, elde edilen desen hidrofilik transfer metodu ile istenilen polietilen tereftalat (PET) yüzeyine transfer edildi. Elde edilen GO desenler iletkenlik kazandırmak amacıyla indirgenerek indirgenmiş grafen oksit (iGO) elde edildi. Elde edilen grafen esaslı iletken desenlerin elektrokimyasal davranışları dönüşümlü voltametri (CV) ve elektrokimyasal impedans spektroskopisi (EIS) teknikleri ile incelendi. Elektrokimyasal karakterizasyon sonucunda en uygun GO miktarı ile elde edilen iletken deseninin 16 µg/mL grafen oksit içeren orta boy elektrot deseni olduğu gözlendi., Graphene defined as "miracle material of the future" is a very thin and strong carbon-based nanomaterial that is a one-atom-thick planar sheet of sp2-bonded carbon atoms which are arranged in a two-dimensional honeycomb lattice. Thanks to its features such as a large surface area, excellent electron transfer performance high mechanical strength and pretty high thermal conductivity features, graphene has taken an important place from the transistors to batteries, from electronic devices to textile products, from drug development to sensors in the fields of physics, chemistry, biology, biotechnology, engineering, medicine and especially in nanotechnology. In this thesis, graphene-based material (reduced graphene oxide) which shows similar characteristics to graphene nanomaterial that is the shining star of nanoscience and nanotechnology, was patternedonto flexible and transparent surfaces using a practical and economical method. For this purpose, graphene oxide (GO) was obtained by chemical oxidation method using graphite as starting material. The structural characterization of GO was performed by Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier Transform infrared (FTIR) spectroscopy and Raman spectroscopy techniques, and the morphological characterization by scanning electron microscope (SEM), transmission electron microscope (TEM) and atomic force microscope (AFM) techniques. The prepared graphene oxide dispersion was filtered by vacuum filtration to the patterned membrane surface with a solid printing device. After this system which provides control of the GO layer thickness, the obtained pattern was transferred onto the desired polyethylene terephthalate (PET) surface by hydrophilic transfer method. The GO patterns were reduced to provide conductivity and reduced graphene oxide (rGO) was obtained. The electrochemical behavior of the graphene based conductive patterns was investigated by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. As a result of electrochemical characterization, it was observed that the most conductive pattern obtained with the optimum amount of GO was a medium-sized electrode pattern containing 16 µg/mL graphene oxide.

Nowadays, dynamic development in nanotechnological sciences is observed. Nanoparticles are frequently used in medicine and pharmacy as delivery systems for different kinds of active substances. One of the latest developed substances, with an unusually wide scope of utility, is graphene. The ways of its use in different fields of industry, not only pharmaceutical and medical, have been a subject of study for many research groups since the moment of its development in 2004. Graphene in pure form is highly hydrophobic. However, the presence of defects on its surface allows chemical modifications to be made, e.g. introduction of oxygen groups by covalent bonding. Also, non-covalent modifications are extensively used, including van der Waals forces, hydrogen bonding, coordination bonds, electrostatic and π-π stacking interactions. Due to the large surface area, graphene can be used in combination therapy, consisting in simultaneous administration of two or more pharmacologically active agents. Another interesting approach is gene therapy. Application of the PEI-graphene oxide system increased the efficacy of transfection. Possibilities of graphene and graphene oxide are not limited to their use as active substance delivery systems. These compounds by themselves were also found to be bacteriostatic and antibacterial agents.

PET je danas jedan od najraširenijih oblika plastike, te se osim za proizvodnju plastičnih boca koristi i za razne industrijske potrebe (uključujući i elektrotehniku). Nanotehnologija je znanost budućnosti, a jedan od ciljeva nanotehnologije je stvaranje novih, poboljšanih materijala, pa se eksperimentira i s PET-om radi dobivanja poboljšanih svojstava. Cilj ovog završnog rada je bio usporediti svojstva čistog PET-a i nanokompozita PET-a korištenjem infracrvene spektroskopije (FTIR). Pokazano je kako se dobiva PET-ov nanokompozit iz običnog PET-a, te kako se proizvode nanopunila, nanodijamanti i grafen, koji se koriste za ispunjavanje polimerne matrice PET-a. Analizirane su promjene u strukturi PET-a i njegovih nanokompozita koje se događaju kad se materijal podvrgne protonskom zračenju. Pokazano je da nanopunila poboljšavaju otpornost polimera na zračenje i da pomažu u održavanju polimerne strukture materijala bez da su značajno poremetili polimernu strukturu svojim prisustvom. Dok se čisti PET skoro u potpunosti amorfizirao pod utjecajem zračenje, nanokompoziti PET-a se počeo kristalizirati čime se smanjila osjetljivost na protonsko zračenje, zbog čega bi se ovi materijali mogli koristiti u okolišu gdje je prisutna visoka količina radijacije. PET is one of most widely used forms of plastic today, and, beside bottle production, is also used for various industrial purposes (including electrical engineering). Nanotechnology is science of the future, and one of the goals of nanotechnology is creation of new, improved materials, and PET is also used in experiments to obtain improved properties. The goal of this bachelor thesis is to compare properties of pure PET and PET nanocomposite using infrared spectroscopy (FTIR). It is shown how to manufacture PET nanocomposite from pristine PET, and how nanofillers are produced, nanodiamond and graphene, which are used to fill PET polymer matrix. Changes in structure of PET and PET nanocomposites, which were subjected to proton irradiation, were analyzed. It's been shown that nanofillers improve irradiation resistance and help maintain polymer structure of the material without significantly disrupting the polymer matrix. While pristine PET almost fully amorphised under proton irradiation, PET nanocomposite material started to crystalise reducing sensitivity of PET to proton irradiation, which implies these materials might be used in high radiation environment.

This is an open access article distributed under the Creative Commons Attribution License., We investigate knee-shaped junctions of semiconductor zigzag carbon nanotubes. Two dissimilar octagons appear at such junctions; one of them can reconstruct into a pair of pentagons. The junction with two octagons presents two degenerate localized states at Fermi energy (E F). The reconstructed junction has only one state near E F, indicating that these localized states are related to the octagonal defects. The inclusion of Coulomb interaction splits the localized states in the junction with two octagons, yielding an antiferromagnetic system. © 2013 W. Jaskólski et al., This work was supported by the Polish National Science Center (Grant DEC-2011/03/B/ST3/00091), the Spanish Ministry of Economy and Competitiveness (Grant nos. FIS2012-33521 and FIS2010-19609-C02-02), the Basque Departamento de Educación and the University of the Basque Country UPV/EHU (Grant no. IT-366-07), the Basque Departamento de Industria and the Diputación Foral de Gipuzkoa under the ETORTEK research program (NANO-IKER Grant no. IE11-304).

Üstün elektrik, mekanik, termal ve optik özellikleri ile grafen, araştırmaların odağında bir materyaldir. İndirgenmiş grafen oksit (RGO) ise grafen elde etmenin en etkili yollarından birisidir. Bu çalışmada modifiye Hummers yöntemi ile sentezlenen grafen oksitlerin (GO) indirgenmesi ile RGO elde edilmiştir. SEM görüntülerinden saydam RGO yapıları tespit edilmiştir. EDX/SEM analizinde, karbon (C) oranı yaklaşık %89 olarak bulunmuştur. FT-IR sonuçları ile GO yapısında var olan hidroksil, karbonil, epoksi ve alkoksi bağlarının RGO yapısından uzaklaştığı anlaşılmaktadır. Raman spektroskopisinde yeni sp2 yapıların oluştuğu ve düzenli yapı miktarının arttığını görülmüştür. XRD analizinde oksidasyon işlemi sırasında oluşan fonksiyonel grupların kimyasal işlem esnasında bozunmaları sonucu RGO’nun katmanları arası d-mesafesi 0,83 nm’den 0,36 nm’ye düştüğü görülmektedir., More recently, graphene, having outstanding electrical, mechanical, thermal and optical properties, have become an important research topic. Reduced graphene oxide (RGO) is one of the most effective way to obtain the graphene. In this study, RGO was obtained by reduction of graphene oxide (GO) synthesized by a modified Hummers method. The transparent structures of RGO have been identified through SEM images. The ratio of carbon (C) was found to be approximately 89% by SEM/EDX analysis. It was proven by FT-IR analysis that hydroxyl, carbonyl, epoxy and alkoxy bonds in GO structure were removed from RGO structure. On the other hand, RAMAN spectroscopic studies showed that the new sp2 structures occurred, and the amount of regular structures increased. XRD analysis indicated that d-spacing between the layers of RGO decreased from 0,83 nm to 0,36 nm due to the degradation of functional groups during the chemical process, which were formed in the oxidation process.