3D Nanomaterials: Fabrication, Properties and Smart Applications
By Reza Abolhassani
Nanoscale materials with multifunctional properties have received increasing interest in scientific and industrial communities because of their versatile applications in advanced technologies. A new class of nanomaterials, so called smart materials, has been recently emerged as very potential candidates for various applications because of their capability to self-respond to any external stimuli (e.g. stress, temperature, light, electric or magnetic field, deformation, electrochemical, pH, etc.) by altering their one or more properties in form of a reliable read out signal. Their extensive applications in healthcare, aerospace, automotive, electronic, smart polymers, smart textile, sensors, medicine, and etc. makes it essential to study and research on this young novel technology. Nanomaterial fabrication in the desired compact form is the most important prerequisite for any scientific and technological development, and nowadays, the key challenge is to design the nanomaterial in 3D complex smart forms which are equipped with right functions and simultaneously are easy to utilise. 
The aim of this PhD project is to synthesise 1D ZnO nanostructures based complex shaped nanostructures and selectively surface engineering of arm morphologies using state-of-the-art micro- and nanofabrication methods for enhancing their optical, electronic, chemical, and mechanical properties which will be carefully characterised, analysed, and understood. The structure-property relationships of these materials will be understood, and they will be explored for applications in various smart technologies in direction of optics, catalysis, energy, sensing, and smart textiles, and they will be utilised for various possible applications.
Supervisor: Yogendra Kumar Mishra

By Cecilie Clausen Fynbo
Graphene-organic semiconductor heterostructures have been proposed as highly efficient organic phototransistors. These heterostructures exploit the high charge mobility in graphene and the optical-spectral-sensitivity of organic semiconductors to obtain high quantum efficiency and high bandwidth. Fabrication of such structures is typically a two-step procedure where the graphene layer is synthesised and transferred to a substrate followed by deposition of the organic semiconductor material. The growth of the organic semiconductor film and the quality of the graphene layer are the limiting factors of such a device as the microscopic morphology, crystal quality, and the interfacial properties of the organic semiconductor film greatly affect the performance of the organic phototransistor. Fortunately, epitaxially grown organic crystals on graphene show highly oriented molecular structures as well as defect-less surfaces. Most reported graphene-organic semiconductor phototransistors use organic semiconductors with absorption in the visible spectrum, only a few have developed devices with absorption in the near infrared regime. One of the materials used in such a device is the fullerene C₆₀. However, C₆₀ molecules have shown to be photochemically instable and responsible for degradation mechanisms in organic solar cells. Therefore, it is suggested to use different diketopyrrolopyrrole-based oligomers and polymer to fabricate graphene-organic semiconductor phototransistors able to detect near infrared light. This project investigates the possibilities of graphene-organic semiconductor heterostructures as these structures are expected to have promising photodetector applications. The aim is to create an organic phototransistor with a high response time and high photoresponsivity, however, these two performance parameters are often a trade-off. To obtain such a device it is critical to minimise the defects in graphene and maximise the absorption and exciton diffusion in the organic semiconductor film which can be done by optimising the molecular alignment. Additionally, the electrode design and organic semiconductor film thickness should also be optimised as they affect the transit time of the photocarriers and the performance criteria of the device, respectively.
Supervisor: Jakob Kjelstrup-Hansen

Applications of Hyperspectral Thermal Imaging
By Mads Nibe Larsen
Infrared thermography is an imaging technique that records long-wave infrared light (8 – 14 µm) and it is often used for remote temperature determination of objects by measuring the amount of thermal radiation they give off. However, different materials have different emission spectra, and the camera must be calibrated to the specific material being imaged. A hyperspectral thermal imaging system can record spectra of every element in the scene, making it possible to segregate multiple materials simultaneously and determine their temperature. This project utilizes a first-order scanning Fabry-Pérot Interferometer (FPI) combined with a thermal camera to capture hyperspectral thermal images. The objective of the project can be split in two: Firstly, an existing prototype of the imaging system must be improved enough that it can become the world’s first commercially available FPI based hyperspectral thermal camera. This includes integration of RGB data in order to incorporate parts of the visible spectrum for improved data analysis. Furthermore, since hyperspectral imaging in the thermal regime is a relatively new and untested technique, finding new applications and associated data analysis tools is a priority. Examples could be detecting and identifying different organic gasses or detect wear and defects in buildings. Secondly, a new thermal radiation sensor will be developed. The highest performing commercially available solutions are very expensive and require cryogenic cooling such as Mercury Cadmium Telluride (MCT) detectors. Microbolometers are a less expensive alternative which do not require additional cooling, but they are, however, much less sensitive. The aim is to fabricate an uncooled graphene field-effect transistor, which utilizes the excellent bolometric properties of graphene and combines it with a partially reflecting Bragg mirror. The graphene is suspended inside a reflecting cavity formed by the mirror and a gold coated substrate, which allow incoming radiation to pass through the graphene multiple times, hereby increasing the probability of absorption. The aim is to fabricate a single pixel detector which will indicate the feasibility of future development of an entire graphene-based focal plane array. This is an industrial PhD-project carried out as a collaboration between Newtec Engineering A/S and SDU.
Supervisor: Jakob Kjelstrup-Hansen