Design and implementation of a light-based IoT (LIoT) node using printed electronics

Abstract. The recent exponential growth of new radio frequency (RF) based applications such as internet of things (IoT) technology is creating a huge bandwidth demand in the already congested RF spectrum. Meanwhile, visible light communication (VLC) is emerging as a technology which can be used as an alternative wireless communications solution which makes no use of the radio spectrum. In addition, continuously powering up the massively deployed IoT nodes is becoming a challenge when it comes to maintenance costs. Development of energy autonomous IoT nodes would certainly assist to solve the energy challenge. Previous work shows that renewable energy sources can be utilized to address the energy requirement of IoT nodes. Under this context, we have developed a light-based energy autonomous IoT (LIoT) prototype. This thesis presents a feasibility study and proof of concept of LIoT, including design, implementation and validation of LIoT nodes and a transmitter unit. Furthermore, the ability of multiuser communication using VLC as well as indoor light-based energy harvesting were demonstrated and tested in this thesis. To make the concept of LIoT more attractive from an implementation standpoint, and to create a future-looking solution, printed electronics (PE) technology was used as a part of the implementation. Two key components of the prototype were based on PE technology, photovoltaic cells used to harvest energy, and displays used to exhibit information transmitted to the LIoT node. In the future, when PE technology becomes more mature, very low-cost, small form-factor and environmentally friendly LIoT nodes could be implemented on thin substrates. A wide array of possible applications can be created combining the concept of light-based IoT with printed electronics. The proposed LIoT concept shows great promise as an enabling technology for 6G

Amphibious Drone

This report details the progress made in continuing the UPLOAD Amphibious Drone Capstone project. Alex Desilets has tasked the team with improving last years design and has offered support with financial and technical matters through the design process. The UPLOAD MK. II team has been tasked with improving the design made by the original UPLOAD team from last year. The team from last year designed a UAV capable of delivering a payload over both land and sea over a range of 5 miles. The drone was to take off and land vertically but y horizontally for better efficiency. UPLOAD was able to successfully design a working control system, unfortunately it was unable to y successfully. UPLOAD MK.II will be focusing on improving last year\u27s design using the control systems designed last year will produce a working prototype by May 2017. 120 concepts were combined and reduced into preliminary prototypes of a winglet, testing rig, and landing system. These designs were modeled through CAD and realized through rapid prototyping. Wind tunnel testing was preformed on the winglet to test for increased efficiency, and stress tests have been preformed on the testing rig and the landing gear to ensure safety

Environmental Friendly Electroless Copper Metallization on FDM Build ABS Parts

Environment- friendly electroless metallization of copper (Cu) on acrylonitrile-butadiene-styrene (ABS) parts was studied in which the parts are fabricated by fused deposition modelling (FDM) route of rapid prototyping (RP) process. This metallization process eliminates etching as well as the use of high cost palladium (Pd) for activation. For surface preparation aluminium (A)-enamel paste was used. Four different acidic baths were used for electroless Cu deposition and these are 15 wt% copper sulfate (CuSO4) with 5 wt% of individual hydrofluoric acid (HF), sulfuric acid (H2SO4), phosphoric acid (H3PO4), nitric acid (HNO3) and acetic acid (CH3COOH) with different deposition time at room temperature. After successfully deposition of Cu on ABS surfaces in different baths, the electroless Cu deposition on ABS surfaces were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Adhesion assessment of samples in different baths was studied. All baths were capable of formation of Cu crystals on ABS surface. However, better results in terms of electrical conductivity and uniformity in deposition surface is obtained in HF, H2SO4 and H3PO4 baths

A Review on Sustainable Inks for Printed Electronics: Materials for Conductive, Dielectric and Piezoelectric Sustainable Inks

In the last decades, the demand for electronics and, therefore, electronic waste, has increased. To reduce this electronic waste and the impact of this sector on the environment, it is necessary to develop biodegradable systems using naturally produced materials with low impact on the environment or systems that can degrade in a certain period. One way to manufacture these types of systems is by using printed electronics because the inks and the substrates used are sustainable. Printed electronics involve different methods of deposition, such as screen printing or inkjet printing. Depending on the method of deposition selected, the developed inks should have different properties, such as viscosity or solid content. To produce sustainable inks, it is necessary to ensure that most of the materials used in the formulation are biobased, biodegradable, or not considered critical raw materials. In this review, different inks for inkjet printing or screen printing that are considered sustainable, and the materials that can be used to formulate them, are collected. Printed electronics need inks with different functionalities, which can be mainly classified into three groups: conductive, dielectric, or piezoelectric inks. Materials need to be selected depending on the ink’s final purpose. For example, functional materials such as carbon or biobased silver should be used to secure the conductivity of an ink, a material with dielectric properties could be used to develop a dielectric ink, or materials that present piezoelectric properties could be mixed with different binders to develop a piezoelectric ink. A good combination of all the components selected must be achieved to ensure the proper features of each ink.This publication is supported by the SUINK project funded by the European Union’s Horizon Europe research and innovation programme under Grant Agreement No. 101070112. Funded by the Basque Government ELKARTEK2021 (KK-2021/00040) and ELKARTEK2023 KK-2023/0005

Microstructure, morphology and device physics of gravure printed and solution processed organic field-effect transistors

This thesis explores the relationship between microstructure, morphology and device physics in gravure printed and solution processed organic field-effect transistors (OFETs). Chapter 1 introduces the key concepts encountered in this work: the properties of organic semiconductors and OFETs; the use of printing techniques in organic electronics; and the relationship between microstructure and OFET performance in poly(3-hexylthiophene) (P3HT). Chapter 2 details the materials and experimental techniques used in this thesis. In Chapter 3, gravure printing is demonstrated for high throughput fabrication of OFETs. Printed devices are achieved with typical saturated mobility of 0.03cm2/Vs and on/off ratio in the range 103:9-4:6, which exceeds that achieved with spin coated devices with the same material system and geometry. Chapter 4 presents a systematic comparison of the microstructure and OFET characteristics of gravure printed and spin coated P3HT thin films. First light scattering is used to understand the conformation of P3HT chains in various solvents, then grazing incidence wide angle X-ray scattering (GIWAXS), absorption characteristics and atom force microscopy (AFM) are used to characterise the microstructure of the P3HT lms. In turn, this is compared to OFET performance. In Chapter 5 two solvent based techniques are investigated as alternatives to thermal annealing as methods to enhance microstructure. A blend of a high and low boiling point solvent is first examined as the casting solvent for P3HT and is found to moderately improve P3HT field-effect mobility. Secondly, solvent vapour treatment (SVT) - exposing a P3HT film to a solvent vapour after spin coating - is studied by in-situ GIWAXS. The time resolved measurement of interchain and interlamella distances allowed the dynamics of SVT to be investigated. SVT was found to decrease P3HT crystallinity, although AFM showed it lead to smoother films. In Chapter 6 two emerging materials are investigated for use in OFETs. Preliminary work on fabricating OFETs with single crystal copper phthalocyanine is presented. Finally, work towards a metal-free OFET is described in which the source and drain electrodes are formed of high conductivity PEDOT deposited by vapour phase polymerisation

Active magnetic bearing for ultra precision flexible electronics production system

Roll-to-roll printing on continuous plastic films could enable the production of flexible electronics at high speed and low cost, but the granularity of feature sizes is limited by the system accuracy. Technologies such as gravure printing and nanoimprint lithography demand a level of rotary motion precision that cannot be achieved with rolling element bearings. Manufacturing tolerances of the rotating parts, thermal drift and process forces in combination with structural compliance add up to additional error motions. In this master by research an active magnetic bearing (AMB) solution is designed for a new, super-sized roll-to-roll flexible electronics production machine, which was so far based on hydrostatic bearings. The magnetic bearing could actively compensate the accumulated synchronous error and maintain high accuracy under all conditions. However, the asynchronous error of a conventional AMB with the required size and power is a problem. In order to reduce the relatively high positioning uncertainty of active magnetic bearings an innovative radial position measurement based on linear, incremental encoders with optical conversion principle is proposed. A commercial encoder scanning head faces a round scale with concentric, coplanar lines on its face. By counting these lines the radial position can be measured. Because such a scale is not readily available, it is made by micro-machining. In experiments, different machining methods are compared. Then a magnetic bearing is built to demonstrate the efficacy of the proposed sensor. As a result, the best measurement noise is 3.5nm at 10kHz and a position uncertainty of approximately 0.25µm has been achieved for the magnetic bearing. These promising results are especially interesting for applications with high precision requirements at low speed of rotation

Liquid cooled micro-scale gradient system for magnetic resonance

Schaltbare magnetische Feldgradientspulen sind ein geeignetes Werkzeug für die Modulation der Kernspinpräzession in der gepulsten Kernspinresonanzspektroskopie und Bildgebung. Die Magnetresonanztomographie von mikroskopischen Proben benötigt starke, schnell schaltbare Magnetfeldgradienten, um diffusionsbedingte Artefakte zu unterdrücken, Suszeptibilitätseffekte abzuschwächen und um die Messzeit zu verkürzen. Verschiedene Techniken können eingesetzt werden, um eine hohe Gradientenintensität zu erreichen, wie zum Beispiel die Erhöhung der Stromstärke oder die Steigerung der Windungsdichte der Feldspule. Ein weiterer, geeigneter technischer Ansatz besteht darin, die Gradientenspulen näher an der Probe zu platzieren. Als Konsequenz wird aber die durch die Joule-Erwärmung verursachte Wärmeentwicklung zu einem zentralen Problem. In dieser Arbeit wird ein neuartiges Design, ein Mikroherstellungsprozess und eine Kernspin-Evaluierung eines Feldgradientenchips präsentiert. Die Gradientenspulen wurden besonders hoch miniaturisiert und durch den Einsatz von verbesserten und neuartigen Strukturierungsverfahren entwickelt. Zuerst wird ein Fertigungsverfahren zur Herstellung einer kompakten Hochfrequenzspule vorgestellt. Durch den Einsatz einer maskenlosen Rückseitenlithographie konnte die Prozesskomplexität reduziert werden. Dieses Verfahren wurde durch Tintenstrahldruck mit Nanopartikeln realisiert, wobei die gedruckten Strukturen selbst als lithographische Maske für die Herstellung einer galvanischen Form dienen. Somit werden die Seitenwände der galvanischen Form durch die gedruckte Seed-Schicht optimal selbst ausgerichtet. Dies ermöglichte eine anisotrope Galvanisierung, um eine höhere elektrische Leitfähigkeit der gedruckten Leiterbahnen zu erzielen. Aus den Erkenntnissen der ausgearbeiteten Herstellungsprozesse wurde ein optimiertes Spulendesign für ein-axiale sowie drei-axiale linearen Gradientenchips entwickelt. Die einachsige lineare $z$-Gradientenspule wurde mit der Stream-Function-Methode berechnet, wobei die Optimierung darauf abgestimmt wurde, eine minimale Verlustleistung zu erzielen. Die Gradientenspulen wurden auf zwei Doppellagen implementiert, die mittels Cu-Galvanik in Kombination mit fotodefinierbaren Trockenfilm-Laminaten aufgebracht wurden. Bei dem hier vorgestellten Herstellungsverfahren diente die erste Metallisierungschicht gleichzeitig dazu, Widerstands-Temperaturdetektoren zu integrieren. Um niederohmige Spulen zu realisieren wurde der Galvanisierungsprozess soweit angepasst, um eine hohe Schichtdicke zu erzielen. Die Chipstruktur beinhaltet ein aktives Kühlsystem, um dem Aufheizen der Spulen entgegenzuwirken. Thermographische Aufnahmen in Kombination mit den eingebetteten Temperatursensoren ermöglichen es, die Erhitzung der Spule zu analysieren, um die Strombelastbarkeit zu ermitteln. Die Gradientenspule wurde mit einer Hochfrequenz-Mikrospule in einer Flip-Chip-Konfiguration zusammengebaut, und mit diesem Aufbau wurde ein eindimensionales Kernspinexperiment durchgeführt. Es wurde eine Gradienteneffizienz von 3.15 $T\,m^{−1}\,A^{−1}$ bei einer Profillänge von 1.2 $mm$ erreicht

Novel Materials, Processing and Device Technologies for Space Exploration with Potential Dual-Use Applications

We highlight results of a broad spectrum of efforts on lower-temperature processing of nanomaterials, novel approaches to energy conversion, and environmentally rugged devices. Solution-processed quantum dots of copper indium chalcogenide semiconductors and multiwalled carbon nanotubes from lower-temperature spray pyrolysis are enabled by novel (precursor) chemistry. Metal-doped zinc oxide (ZnO) nanostructured components of photovoltaic cells have been grown in solution at low temperature on a conductive indium tin oxide substrate. Arrays of ZnO nanorods can be templated and decorated with various semiconductor and metallic nanoparticles. Utilizing ZnO in a more broadly defined energy conversion sense as photocatalysts, unwanted organic waste materials can potentially be repurposed. Current efforts on charge carrier dynamics in nanoscale electrode architectures used in photoelectrochemical cells for generating solar electricity and fuels are described. The objective is to develop oxide nanowire-based electrode architectures that exhibit improved charge separation, charge collection and allow for efficient light absorption. Investigation of the charge carrier transport and recombination properties of the electrodes will aid in the understanding of how nanowire architectures improve performance of electrodes for dye-sensitized solar cells. Nanomaterials can be incorporated in a number of advanced higher-performance (i.e. mass specific power) photovoltaic arrays. Advanced technologies for the deposition of 4H-silicon carbide are described. The use of novel precursors, advanced processing, and process studies, including modeling are discussed from the perspective of enhancing the performance of this promising material for enabling technologies such as solar electric propulsion. Potential impact(s) of these technologies for a variety of aerospace applications are highlighted throughout. Finally, examples are given of technologies with potential spin-offs for dual-use or terrestrial applications

Terahertz antenna design for future wireless communication

A Terahertz (THz) antenna with a size of a few micrometres cannot be accomplished by just reducing the extent of a traditional metallic antenna down to a couple of micrometres. This approach has several downsides. For example, the low mobility of electrons in nanoscale metallic structures would result in high channel attenuation. Thus, using traditional micrometre metallic antennas for THz wireless communication becomes unfeasible. The THz band refers to the electromagnetic spectrum between the microwave and infrared frequency bands, which is colloquially referred to as the band gap due to the lack of materials and technological advancements. As opposed to their visible-spectrum features, metals such as gold and silver, which typically exhibit surface plasmon polaritons (SPPs), have completely different THz physical properties. 2D materials, which typically refer to single-layer materials, have been the focal point of researchers since the advent of graphene. 2D materials, for example, graphene, perovskite, and MoS2 (TMDs), provide a ground-breaking stage to control the propagation, modulation, and detection of THz waves. Moreover, 2D materials can enable the propagation of SPP waves in the THz band. These materials offer a promise of a future technological revolution. Combined with other profound advantages in lightweight, mechanical flexibility, and environmental friendliness, 2D materials can be used to fabricate low-cost wearable devices. This study also reported CH3NH3PbI3 perovskite as a promising material for THz antennas for wearable applications. CH3NH3PbI3 has a high charge carrier mobility and diffusion length, indicating that this material is a potential candidate for antenna design. The attractive feature about perovskite, graphene and other 2D materials is the ultra-high specific surface areas that enable their energy band structures to be sensitive to external basing. In the literature, scientists have tested a wide range of nano-antenna designs using modelling and simulation approaches. Nano-antenna fabrication and measurement using 2D materials is still the missing piece in the THz band. The design, fabrication, and measurement of THz antennas based on 2D materials for wearable wireless communication is the primary goal of this PhD study, including designing, fabrication, and measurement. In this study, we have designed, fabricated, and measured five different designs using different materials in the THz band, which will pave the way for enabling future THz short-range wireless communication

Effect of Cutting Parameters on Micro Drilling Characteristics of Incoloy 825

The study focuses on the micro drilling of Incoloy 825 alloy under flood cutting condition. Micro drilling on nickel based superalloy is very challenging process due to the material properties, operating conditions, low thermal conductivity and high quality requirements. Due to low thermal conductivity of material heat is concentrated near tool tip and unable to dissipate for which tool wear occurs. The current study described the machinability of Incoloy 825 in micro drilling operation and also the effect of spindle rpm and feed rate on thrust force, torque, radial component force, tangential component forces, oversize diameter and white layer thickness. The current study investigates the influence of micro drilling parameters on surface profile and circumferential damage of micro holes (in terms of damaged layer thickness). ANSYS simulation was carried out to theoretically determine and evaluated necessary data like equivalent stress and deformation. Statistical analysis was also carried out to develop predictive models for various output characteristics