title: Synthesis and characterisation of anisotropic metal chalcogenide nanomaterials
Creators: name: Ratkic, Rolanda
Publisher: name: TU Wien
Year: 2018
Subjects: subject: metal chalcogenide
subject: nanomaterials

description: Daraus resultierten dunkelgrüne Kupfersulfid Nanoplättchen, welche durch TEM Bilder eindeutig erkennbar sind und bei sinkender Reaktionstemperatur kleiner werden. Diese wurden mit XRD gemessen und weisen auf eine eindeutige hexagonale Struktur hin. UV-VIS Messungen zeigen eine Plasmon Absorption, sowie eine Bandlückenabsorption, diese Eigenschaften könnten zum Beispiel bei Sensoren angewandt werden. Außerdem wurden schwarze Kupferselenid Nanodrähte sowie dreieckige Nanoplättchen durch Temperatur Erhöhung hergestellt und mittels TEM Bilder erstellt. Die Nanoplättchen weisen auch auf Bandlückenund Plasmon Absorption hin und die Kristallstrukturanalyse (XRD) ergibt kubisch-flächenzentrierte Kirstallstruktur. Darüber hinaus wurden dunkelbraune dünne Eisensulfid und schwarze Eisenselenid Nanoblätter, unterschiedlicher Größe je nachdem Fe(II)-Salz oder Fe(III)-Salz als Edukt verwendet, sowie schwarze Nickelselenid Nanorollen hergestellt und mittels TEM Bilder angefertigt. Die Eisenselenid Nanoblätter ergeben durch die XRD-Messung eine eindeutige orthorhombische Kristallstruktur.
description: The desire of controllable size and shapes with different nanomaterials is motivated because of their properties and resulting applications. Due to the large amount of surface atoms, nanomaterials differ from their bigger counterparts. Properties like the melting point, electric conductivity, optical characteristics or general chemical activity of a molecule change. This thesis uses an efficient ‘hot injection approach synthesis in oleylamine producing anisotropic two-dimensional nanomaterials. The solvent oleylamine additionally acts as stabilizer and reducing agent. Various metal-chalcogenide nanomaterials are produced with different sizes and shapes. The chalcogenides, sulphur and selenium, were reduced to sulphide and selenide in oleylamine. The metal salts used (CuCl2*2H2O, FeCl2*4H2O, FeCl3*6H2O and NiCl2*6H2O) were dissolved in NMP beforehand and afterwards added to the stirring hot oleylamine-chalcogen mix via ‘hot injection. This results in dark-green copper sulphide nanoplates, which are getting smaller with decreasing temperature and are clearly seen in TEM images. These nanoplates were measured with XRD and show a clear hexagonal pattern. Optical measurements such as UV-VIS show a plasmon and a band gap absorption, which could be used in sensor applications. Apart from that black copper selenide nanowires, and with increasing temperature, triangular copper selenide nanoplates have been produced. TEM images were taken and optical measurements show band gap and plasmon absorption as well. XRD measurements show a face centred cubic pattern. Furthermore, dark-brown iron sulphide and black iron selenide nanosheets as well as nickel selenide nanoscrolls have been produced. Depending on which iron-salt educt (Fe[II]-salt or Fe[III]-salt) has been used, sizes of the nanosheets vary. TEM pictures were taken of all nanomaterials and the XRD measurement of the iron selenide nanosheets show an orthorhombic pattern.