The employment of printing techniques as cost-effective methods to fabricate low cost, flexible, disposable and sustainable solar cells is intimately dependent on the substrate properties and the adequate electronic devices to be powered by them. Among such devices, there is currently a growing interest in the development of user-oriented and multipurpose systems for intelligent packaging or on-site medical diagnostics, which would greatly benefit from printable solar cells as their energy source for autonomous operation.
Part of the book: Nanostructured Solar Cells
The massification of Internet of Things (IoT) and Smart Surfaces has increased the demand for nanomaterials excelling at specific properties required for their target application, but also offering multifunctionality, conformal integration in multiple surfaces and sustainability, in line with the European Green Deal goals. Metal oxides have been key materials for this end, finding applications from flexible electronics to photocatalysis and energy harvesting, with multicomponent materials as zinc tin oxide (ZTO) emerging as some of the most promising possibilities. This chapter is dedicated to the hydrothermal synthesis of ZTO nanostructures, expanding the already wide potential of ZnO. A literature review on the latest progress on the synthesis of a multitude of ZTO nanostructures is provided (e.g., nanowires, nanoparticles, nanosheets), emphasizing the relevance of advanced nanoscale techniques for proper characterization of such materials. The multifunctionality of ZTO will also be covered, with special attention being given to their potential for photocatalysis, electronic devices and energy harvesters.
Part of the book: Novel Nanomaterials
The ever-growing global market for smart wearable technologies and Internet of Things (IoT) has increased the demand for sustainable and multifunctional nanomaterials synthesized by low-cost and energy-efficient processing technologies. Zinc oxide (ZnO) is a key material for this purpose due to the variety of facile methods that exist to produced ZnO nanostructures with tailored sizes, morphologies, and optical and electrical properties. In particular, ZnO nanostructures with a porous structure are advantageous over other morphologies for many applications because of their high specific surface area. In this chapter, a literature review on the latest progress regarding the synthesis and applications of ZnO with a porous morphology will be provided, with special focus on the synthesis by microwave hydrothermal method of these nanomaterials and their potential for application in energy harvesting devices. Nanogenerators of a composite made by polydimethylsiloxane (PDMS) and porous ZnO nanostructures were explored and optimized, with an output voltage of (4.5 ± 0.3) V being achieved for the best conditions. The daily life applicability of these devices was demonstrated by lighting up a commercial LED, by manually stimulating the nanogenerator directly connected to the LED.
Part of the book: Nanopores
Zinc oxide (ZnO) is a widely explored semiconductor metal oxide. This material has interesting properties for several research areas, including energy storage and harvesting, sensing and electronic applications. Its versatility has led to the development of various approaches for synthesizing nanostructures with different morphologies according to the application. In this chapter, a literature review on vapor phase and solution phase synthesis approaches for synthesizing one-dimensional (1D) ZnO nanostructures on different substrates will be provided to establish a comparison between different processes’ parameters. Since hydrothermal synthesis is the most widely used approach for growing ZnO on different substrates due to its simplicity and cost-effectiveness, the principles of this technique will be detailed. As an experimental demonstration of such technique, novel results obtained at CENIMAT on microwave-assisted hydrothermal synthesis of ZnO nanorods, exploring the influence of seed layer thickness, ultraviolet/ozone (UVO) treatment to this layer, and synthesis time and temperature on the nanostructures’ morphology, will be presented. The nanostructures’ length, diameter and density were measured to establish a correlation between synthesis conditions and nanostructures’ features. A seed layer thickness of 100 nm, a 5 min UVO treatment, and a synthesis time and temperature of 60 min and 100°C led to the formation of ZnO nanorods with increased length and aspect ratio.
Part of the book: Zinc Oxide Nanoparticles - Fundamentals and Applications [Working title]