Saturated markets and a competitive business climate create pressure on organisation to find new ways to remain competitive and differentiated towards competitors. One new strategy is to adapt a more service oriented business, and more specifically a concept call solutions. Solutions is about moving from only selling e.g. products or single services, to offer a whole solution to cover more needs, an offer usually created together with the customers. This demand on the market together with limited research on the concept of solution, makes it an interesting area to study. The purpose with the study was to describe the whole solution process between the supplying firm and the customer. In order to do so, a longitudinal, dynamic model based on extant literature was developed, which consisted of three stages and 11 important factors throughout these three stages. The primary data collection came from interviews with managers from five companies, all experienced within the area of solution strategy. Out of the eleven theoretical factors, four factors were explicitly highlighted as most important.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第17161号 / 工博第3651号 / 新制||工||1554(附属図書館) / 29900 / 京都大学大学院工学研究科電子工学専攻 / (主査）教授 藤田 静雄, 教授 髙岡 義寛, 教授 川上 養一 / 学位規則第4条第1項該当

Nanomaterials have been served as essential building blocks in the era of nanotechnology. Nanomaterials often exhibit different properties compared to their bulk phase, due to heavily enlarged portion of surface characteristics to the bulk. Beyond the simple size- effect, nanomaterials can be classified into 0D, 1D, and 2D materials depends on the number of restricted dimensionalities. They exhibit different unique properties and transport mechanism due to the quantum confinement effect. MXenes are one of the latest additions of 2D material family that can be obtained by selective chemical etching and exfoliation of layered ternary precursors (Mn+1AXn phases). Due to the unique etch process, surface functional groups (such as oxygen, hydroxyl, fluorine, etc) are formed at the surface of MXenes. This benefits MXenes for stable aqueous dispersions due to their hydrophilic surface. The coexistence of hydrophilicity and high electrical conductivity promised MXenes in superior performance in electrochemical energy storage and electromagnetic interference shielding applications. These characteristics are equally important for electronic applications. From the synthesis of MXene suspension to thin film deposition by spray-coating and photolithography patterning of MXene films are discussed for electronic device applications of MXenes. Vacuum-assisted filtration method was used for Mo-based MXene freestanding papers for investigation of thermoelectric energy harvesting performances. Both n-type ZnO and p-type SnO thin film transistors with MXene electrical contacts (gate, source, and drain electrodes) have been demonstrated by lift-off patterning method. Their complementary metal-oxide-semiconductor (CMOS) inverter exhibits a high gain value of 80 V/V at a supply voltage of 5 V. The lift-off patterning is simple but effective method for top-contact electrode patterning. However, it has a disadvantage of remaining sidewall-like MXene residue, resulting in leakage issues in the bottom-contact transistor structure. Hence, dry-etch patterning method is developed which allows direct patterning of MXene nanosheet thin films through conventional photolithography process. The conductive MXene electrode array was integrated into a quantum dot electric double layer transistors by all solution processes, which possess impressive performance including electron mobility of 3.3 cm2/V·s, current modulation of 104, threshold voltage as low as 0.36 V at low driving gate voltage range of only 1.25 V.

Metal-halide perovskites have attracted intense research endeavors because of their excellent optical and electronic properties. Different kinds of electronic and optoelectronic devices have been fabricated using perovskites. A feasible approach to utilize these properties in real device applications with improved performance and new functionalities is by fabricating heterostructures with extraneous materials. We have developed mixed-dimensional heterostructure systems using three-dimensional (3D) metal-halide perovskites and different types of different two-dimensional (2D) materials, including semimetal graphene, semiconducting phosphorus-doped graphitic-C3N4 sheets (PCN-S), and plasmonic Nb2CTx MXenes. First, selective growth of single-crystalline MAPbBr3 platelets on monolayer graphene by chemical vapor deposition (CVD) is achieved to prepare the MAPbBr3/graphene heterostructures. P-type doping from MAPbBr3 is observed in the monolayer graphene with a decreased work function of 272 meV under illumination. The photoresponse of the fabricated phototransistor heterostructure verifies the enhanced p-type character in graphene. Such kind of charge transfer can be used to improve device performance. Then, bulk-heterojunctions made of MAPbI3-xClx and PCN-S are prepared in solution. The matched band diagram and the midgap states in PCN-S present a convenient and efficient approach to reduce the dark current and increase the photocurrent of the as-fabricated photodetectors. As a result, the on/off ratio increases from 103 to 105, and the detectivity is up to 1013 Jones with an order of magnitude enhancement compared to the perovskite-only device. Last, plasmonic Nb2CTx MXenes and MAPbI3 heterostructures are prepared for photodiodes to broaden the detection band to near-infrared (NIR) lights. The use of the perovskite layer expanded the operation of the diode to the visible range while suppressing the dark current of the NIR-absorbing Nb2CTx layer. The fabricated photodiode reveals a detectivity of 0.25 A/W with a linear dynamic range of 96 dB in the visible region. In the NIR region, the device demonstrates an increased on/off ratio from less than 2 to near 103 and much faster response times of less than 30 ms. The improved performance is attributed to the passivation of the MAPbI3/Nb2CTx interface.

No description available.

In this research, the contents are divided into two sections. In the first section, we investigated carrier transport behavior of organic optoelectronic devices by using space charge limited current(SCLC) method. Firstly, we fabricated a hole-only device (ITO/Spiro-MeOTAD/Al) for Sprio-MeOTAD and the current density¡V voltage(J-V) characteristics of the device was measured. The J-V characteristics of the device do not match with SCLCs very well at high voltage since the number of hole injection was not enough to achieve SCLCs condition. To enhance the injection of hole carrier into the organic layer, a MoO3 buffer layer was inserted between ITO electrode and organic layer. The current density in device with MoO3 buffer layer achieved 5 times enhancement, indicating that the concentration of hole in MoO3 device is increment. Hence, we succeeded in making the J-V characteristics of the hole-only device to match with SCLCs well at high voltage, and the hole mobility of Sprio-MeOTAD estimated by SCLCs was 1.44¡Ñ10-4cm2/Vs. Li salt was also doped into Sprio-MeOTAD as an n-type dopant. We found that Li salt could form hole-traps in Sprio-MeOTAD, which reduced hole carriers in Spiro-MeOTAD. The current density of the device was decreased, and the device could not achieve SCLCs condition at high voltage. In the second section, we use two novel iridium(Ir) complexes to fabricate blue-green emitting devices by solution process. First, we obtained optimum concentration of phosphorescent emitters by controlling of the dopants concentration. Then, we adjusted the thickness of the electron injection layer, hole injection layer, and emission layer to design more suitable device structure. Finally, we succeeded in fabricating blue-green light emitting devices. The maxima luminescence was 37.7cd/m2 and maxima current efficiency was 1.68 cd/A in the Ir complex based devices.

The aim of this document is to familiarize first grade elementary school readers with the critical points in solving word problems in mathematics and to analyze various problem- solving strategies in concrete tasks. Primarily, the document is focused on determining pupils' difficulties and acquiring information about the problem-solving process through a written record of the solution and subsequent in-depth interviews. The theoretical part is divided into six sections dealing with terminology (e.g. word problem) and the areas influencing success in the solution of word problems and partial processes. The practical part contains an analysis of each pupil's solutions and a description of phenomena found in them, together with the grading teacher's help. KEYWORDS Word problem, pupil's solutions, analysis of interviews, questions, solution process

Metal oxide nanocrystals have attracted significant interests due to their unique chemical, physical, and electrical properties which depend on their size and structure. In this study, a continuous flow microreactor system was employed to synthesize metal oxide nanocrystals in aqueous solution. Assembly of nanocrystals is considered one of the most promising approaches to design nano-, microstructures, and complex mesoscopic architectures. A variety of strategies to induce nanocrystal assembly have been reported, including directed assembly methods that apply external forces to fabricate assembled structures. In this study ZnO nanocrystals were synthesized in an aqueous solution using a continuous flow microreactor. The growth mechanism and stability of ZnO nanocrystals were studied by varying the pH and flow conditions of the aqueous solution. It was found that convective fluid flow from Dean vortices in a winding microcapillary tube could be used for the assembly of ZnO nanocrystals. The ZnO nanocrystal assemblies formed three-dimensional mesoporous structures of different shapes including a tactoid, a retangle and a sphere. The assembly results from a competing interaction between electrostatic forces caused by surface charge of nanocrystals and collision of nanocrystals associated with Dean vortices. The as synthesized colloidal ZnO nanocrystals or assembly were directly deposited onto a substrate to fabricate ZnO nanostructured surfaces. The rectangular assembly led to flower-like ZnO nanostructured films, while the spherical assembly resulted in amorphous ZnO thin film and vertical ZnO nanowire (NW) arrays. In contrast to the formation of flower structure or amorphous thin film, only colloidal ZnO nanocrystals were used as the building blocks for forming vertical ZnO NW arrays. This study demonstrates the versatility of the microreactor-assisted nanomaterial synthesis and deposition process for the production of nanostrucuturesres with various morphologies by tuning the physical parameters while using the same chemical precursors for the synthesis. ZnO flower structure was coated on a microwick structure to improve the capillary flow. The coated microwick structure showed an enhanced capillary rise, which was attributed to the hydrophilic property and geometrical modification of ZnO nanostructure. Two-phase boiling heat transfer was performed using ZnO nanostructured surfaces. ZnO nanocoating altered the important characteristics including surface roughness and wettability. Hydrophilic nature of the ZnO nanocoating generally enhanced the boiling heat transfer performance, resulting in higher heat transfer coefficient (HTC), higher critical heat flux (CHF), and lower surface superheat comparing to the bare surface. Octahedral SnO and porous NiO films, fabricated by a continuous flow microreactor system, were suggested as potential boiling surfaces for the high porosity and irregularity of their structures. / Graduation date: 2013

Une cellule photovoltaïque organique est constituée d’une couche photoabsorbante comprise entre deux électrodes dont l’une au moins est transparente. Généralement, les cellules sont illuminées au travers de l’électrode inférieure transparente d’oxyde d’indium dopé à l’étain (ITO). Néanmoins, de nombreuses applications comme l’automobile nécessitant un éclairage par le dessus du module, nous nous sommes intéressés à l'élaboration de cellules photovoltaïques sur substrat flexible, avec l'électrode inférieure opaque et l'électrode transparente déposée sur le dessus de la cellule. Deux types d'architectures ont été développés. Dans le premier cas, la cellule solaire organique finale a été entièrement déposée par des techniques de dépôt en voie liquide avec les deux électrodes en PEDOT:PSS imprimées par jet d’encre. Dans le second cas, les cellules ont été élaborées sur électrode d'argent avec une électrode supérieure transparente tricouche oxyde/métal/oxyde (MoO3/Ag/MoO3) évaporée thermiquement. Les cellules solaires organiques réalisées selon la seconde architecture ont été connectées en série afin de créer un module photovoltaïque organique. Ce dernier a permis d’alimenter et de faire briller une LED. / An organic solar cell is made of a photoactive layer sandwiched between two electrodes among which one at least is transparent. Usually, solar cells are illuminated through the tin-doped indium oxide (ITO) bottom transparent electrode. Nevertheless, many applications like automobile requiring illumination from above the module, we designed photovoltaic cells on a flexible substrate, with an opaque bottom electrode and a top transparent one. Two types of architectures were developed. At first, the final organic solar cell was fully deposited by solution-process with both electrodes made of ink-jet printed PEDOT:PSS. Then the cells were elaborated on a silver bottom electrode with a transparent evaporated oxide/metal/oxide (MoO3/Ag/MoO3) top electrode. The organic solar cells made according to the second structure were connected in series to create an organic photovoltaic module. It allowed to power and shine a white LED.

Cette thèse est consacrée à la production de matériaux 2D en phase liquide, en utilisant des approches pouvant permettre la production en masse de graphène et de matériaux apparentés. Notre objectif est de surmonter certains problèmes critiques pour le traitement et l'utilisation pratique des encres à base de matériaux 2D et de fournir une compréhension approfondie de la relation structure-propriétés dans ces matériaux, constituant des étapes obligatoires pour leurs applications futures. Cette thèse porte principalement sur l'UILPE et l'exfoliation électrochimique du graphène et du disulfure de molybdène (MoS2), qui ont été choisis comme matériaux prototypes à 2 dimensions. Les approches synthétiques sont combinées à une caractérisation physico-chimique des matériaux produits, à l'aide de techniques telles que l'AFM, la microscopie électronique, la spectroscopie XPS et Raman, ainsi qu'à une caractérisation électrique. Des applications dans le domaine de la détection et de l'électronique ont été explorées et ont permis de démontrer que des approches d'exfoliation en phase liquide pouvaient être utilisées pour obtenir un contrôle précis des propriétés des matériaux 2D ouvrant la voie à leur intégration en tant que matériaux actifs dans de nouveaux dispositifs multifonctionnels. / This thesis is devoted to the production in liquid-phase of two-dimensional materials, by using approaches that may enable mass production of graphene and related materials. We aim to overcome some issues that are critical for the processing and practical use of 2D materials-inks and to provide a deep understanding of the structure-properties relationship in such materials being mandatory steps toward their future applications. This thesis mainly focuses on ultrasound-induced liquid-phase exfoliation and electrochemical exfoliation of graphene and molybdenum disulfide, which have been chosen as prototypical 2D materials. The synthetic approaches have been combined with a multiscale physico-chemical and electrical characterization of the produced materials, by employing techniques such as AFM, XPS and Raman spectroscopy. Applications in the field of sensing and electronics have been explored and allowed to demonstrate that liquid-phase exfoliation approaches can be conveniently employed to achieve a fine control on the properties of 2D materials paving the way to their integration as active materials in novel multifunctional devices.