Browsing by Author "Tittonen, Ilkka Juhani"
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Item InSb Nanowire Direct Growth on Plastic for Monolithic Flexible Device Fabrication(AMERICAN CHEMICAL SOCIETY, 2022-01-25) Khayrudinov, Vladislav; Koskinen, Tomi; Grodecki, Kacper; Murawski, Krzysztof; Kopytko, Małgorzata; Yao, Lide; Jiang, Hua; Tittonen, Ilkka Juhani; Lipsanen, Harri; Haggren, Tuomas; Department of Electronics and Nanoengineering; Department of Applied Physics; Ilkka Tittonen Group; NanoMaterials; Harri Lipsanen Group; Military University of Technology WarsawWe report direct growth of InSb nanowires (NWs) and monolithic device fabrication on flexible plastic substrates. The nanowires were grown using metal–organic vapor-phase epitaxy (MOVPE) in self-catalyzed mode. The InSb NWs are shown to form in the zinc-blende crystal structure and to exhibit strong photoluminescence at room temperature. The NW array light-trapping properties are evidenced by reflectance that is significantly reduced compared to bulk material. Finally, the InSb NWs are used to demonstrate a metal–semiconductor–metal photoresistor directly on the flexible plastic substrate. The results are believed to advance the integration of III–V nanowires to flexible devices, and infrared photodetectors in particular.Item Solar-Powered Carbon Fixation for Food and Feed Production Using Microorganisms—A Comparative Techno-Economic Analysis(AMERICAN CHEMICAL SOCIETY, 2020-12-29) Nappa, Marja; Lienemann, Michael; Tossi, Camilla; Blomberg, Peter; Jäntti, Jussi; Tittonen, Ilkka Juhani; Penttilä, Merja; Department of Electronics and Nanoengineering; Ilkka Tittonen Group; VTT Technical Research Centre of FinlandThis study evaluates the techno-economic feasibility of five solar-powered concepts for the production of autotrophic microorganisms for food and feed production; the main focus is on three concepts based on hydrogen-oxidizing bacteria (HOB), which are further compared to two microalgae-related concepts. Two locations with markedly different solar conditions are considered (Finland and Morocco), in which Morocco was found to be the most economically competitive for the cultivation of microalgae in open ponds and closed systems (1.4 and 1.9 € kg–1, respectively). Biomass production by combined water electrolysis and HOB cultivation results in higher costs for all three considered concepts. Among these, the lowest production cost of 5.3 € kg–1 is associated with grid-assisted electricity use in Finland, while the highest production cost of >9.1 € kg–1 is determined for concepts using solely photovoltaics and/or photoelectrochemical technology for on-site electricity production and solar-energy conversion to H2 by water electrolysis. All assessed concepts are capital intensive. Furthermore, a sensitivity analysis suggests that the production costs of HOB biomass can be lowered down to 2.1 € kg–1 by optimization of the process parameters among which volumetric productivity, electricity strategy, and electricity costs have the highest cost-saving potentials. The study reveals that continuously available electricity and H2 supply are essential for the development of a viable HOB concept due to the capital intensity of the needed technologies. In addition, volumetric productivity is the key parameter that needs to be optimized to increase the economic competitiveness of HOB production.