Ultrathin Metal Hydroxide/Oxide Nanowires: Crystal Growth, Self-Assembly, and Fabrication for Optoelectronic Applications

Abstract

The fundamental understanding of transition metal oxides nanowires’ crystal growth to control their anisotropy is critical for their applications in miniature devices. However, such studies are still in the premature stage. From an industrial point of view, the most exciting and challenging area of devices today is having the balance between the performance and the cost. Accordingly, it is essential to pay attention to the controlled cost-effective and greener synthesis of ultrathin TMOS NWs for industrial optoelectronic applications. This chapter provides a comprehensive summary of fundamental principles on the preperation methods to make dimensionality controlled anisotropic nanowires, their crystal growth studies, and optical and electrical properties. The chapter particularly addresses the governing theories of crystal growth processes and kinetics that controls the anisotropy and dimensions of nanowires. Focusing on the oriented attachment (OA) mechanism, the chapter describes the OA mechanism, nanocrystal’s self-assembly, interparticle interactions, and OA-directed crystal growth to improve the state-of-the art kinetic models. Finally, we provide the future perspective of ultrathin TMOS NWs by addressing their current challenges in optoelectronic applications. It is our understanding that the dimension, and single crystallinity of nanowires are the main contributors for building all functional properties, which arise from quasi-1-D confinement of nanowire growth.

Oriented Attachment Crystal Growth Dynamics of Anisotropic One-dimensional Metal/Metal Oxide Nanostructures: Mechanism, Evidence, and Challenges

“…The 1D electronic pathways to accumulate effective charge transportation and larger surface area of anisotropic nanostructures provide a profound impact in nanoelectronics and nanodevices [5]. Therefore, 1D transition metal/metal oxides crystalline nanomaterials are critical building blocks for the next-generation highperformance integrated circuits and Internet of things (IoT) applications [6][7][8][9].…”

Nanoscopic Insight into Sol–Gel Chemical Kinetics of Oriented Attachment Crystal Growth in Anisotropic Copper Hydroxide Nanowires

“…The quantum confinement of the electrons by the potential wells of metal oxides that is, copper oxide nanowires, controls the materials' characteristics such as high surface-to-volume ratio, increased colloidal stability, and high crystallinity for various opportunities in miniaturized high-performance devices including batteries, microelectronics, solar cells, optical devices, energy devices, and medical imaging. 5,6 The nucleus structure, reaction conditions, 7 and crystal facet-specific adsorbate effects can control the shape, lateral dimension, and aspect ratio. These factors promote controlled single-crystal nanowire growth with an anisotropic lattice orientation.…”

“…The understanding of quantum-size effects in single-crystal metal oxide nanowires is crucial for their successful translation and integration into next-generation electronics, optoelectronics, and photonics. − Their anisotropic nature enables unique functional properties, including new functionalities arising from confined quasi-1D nanowire growth. The quantum confinement of the electrons by the potential wells of metal oxides that is, copper oxide nanowires, controls the materials’ characteristics such as high surface-to-volume ratio, increased colloidal stability, and high crystallinity for various opportunities in miniaturized high-performance devices including batteries, microelectronics, solar cells, optical devices, energy devices, and medical imaging. , The nucleus structure, reaction conditions, and crystal facet-specific adsorbate effects can control the shape, lateral dimension, and aspect ratio. These factors promote controlled single-crystal nanowire growth with an anisotropic lattice orientation. , However, to date, direct observation and a fundamental understanding of the kinetics and mechanism of nanocrystal formation, the spatial interactions between nanocrystals, and their structural evolution to 1-D anisotropic nanowires in colloidal solutions remain unclear …”