Over the last two decades, oxide nanostructures have been continuously evaluated and used in many technological applications. The advancement of the controlled synthesis approach to design desired morphology is a fundamental key to the discipline of material science and nanotechnology. These nanostructures can be prepared via different physical and chemical methods; however, a green and ecofriendly synthesis approach is a promising way to produce these nanostructures with desired properties with less risk of hazardous chemicals. In this regard, ZnO and TiO2 nanostructures are prominent candidates for various applications. Moreover, they are more efficient, non-toxic, and cost-effective. This review mainly focuses on the recent state-of-the-art advancements in the green synthesis approach for ZnO and TiO2 nanostructures and their applications. The first section summarizes the green synthesis approach to synthesize ZnO and TiO2 nanostructures via different routes such as solvothermal, hydrothermal, co-precipitation, and sol-gel using biological systems that are based on the principles of green chemistry. The second section demonstrates the application of ZnO and TiO2 nanostructures. The review also discusses the problems and future perspectives of green synthesis methods and the related issues posed and overlooked by the scientific community on the green approach to nanostructure oxides.

https://www.mdpi.com/1420-3049/26/8/2236/pdf

Green Synthesis and Applications of ZnO and TiO2 Nanostructures.

A new strategy of binary-size particles model for fabricating fine grain, high density and low resistivity ITO target

Designing high energy storage performance BSZT-KNN ceramics

Decoration of indium tin oxide nanoparticles with different crystal structures and morphologies on polypropylene separator for Li-S battery

Controllable phase transition ITO nano powders and temperature-structure sensitivity

Fabrication of monodisperse ITO submicro-spheres using l-Histidine-assisted one-step solvothermal method

Hexagonal-phase indium tin oxide nanoparticle (h-ITO NP) is a high-temperature and high-pressure phase, and its preparation is more difficult than the cubic one. In this work, low-resistivity and single hexagonal-phase ITO NPs were synthesized through a binary solvothermal method of deionized water (DI water) and glycerol (GL) at relatively mild conditions combined with post-heat treatment. The effects of experimental parameters such as the volume ratios of DI water and GL, reaction time and temperature on the phase, morphology as well as electrical resistivity of h-ITO NPs were explored systematically. The results showed that the reaction time can be as short as 30 min when the single hexagonal-phase ITO NPs were synthesized at 200 °C. And the h-ITO NPs can also be synthesized when the temperature was as low as 110 °C by an 8-h reaction. The lowest resistivity of 1.258 Ω cm can be reached when the volume ratio of DI water to GL was 1:1, the reaction temperature and time were 200 °C and 8 h, respectively. Moreover, the mechanism of the influence of experimental conditions on the resistivity of ITO NPs was also analyzed.

Synthesis of hexagonal-phase indium tin oxide nanoparticles by deionized water and glycerol binary solvothermal method and their resistivity

A new strategy for decreasing resistivity while increasing visible light transmission of indium tin oxide nanoparticles (ITO NPs) was reported in this paper. Cubic phase ITO NPs with high dispersion were synthesized by coprecipitation method with cetyltrimethylammonium bromide (CTAB) assisted. The effects of dispersion on the optical and electrical properties of ITO NPs were investigated systematically. Surface potential of ITO NPs synthesized with 1.5 g/L of CTAB was increased from − 4.5 to 13.0 mV, resulting in an increase in visible light transmittance of ITO NPs from 70 to 92% and a decrease in resistivity from 6.5 × 10−1 to 3.5 × 10−1 Ω cm. The fitting equation between the visible light transmittance (T) of ITO NP and its absolute value of Zeta potential (μ) was $$T = 60.862 + 2.287 \mu$$
 , while the fitting equation of its resistivity (ρ) and absolute value of Zeta potential (μ) was $$\rho = 0.7968 - 0.0350 \mu$$
 . This result showed that the dispersion of ITO NPs had a great contribution to improving their optical and electrical properties. And the mechanism of the influence of dispersion on optical and electrical properties of ITO NPs was also discussed.

Effect of dispersion on visible light transmittance and resistivity of indium tin oxide nanoparticles prepared by cetyltrimethylammonium bromide-assisted coprecipitation method

Yunqian Ma

Papers

A new strategy of binary-size particles model for fabricating fine grain, high density and low resistivity ITO target

Fabrication of monodisperse ITO submicro-spheres using l-Histidine-assisted one-step solvothermal method

Controllable phase transition ITO nano powders and temperature-structure sensitivity

Synthesis of hexagonal-phase indium tin oxide nanoparticles by deionized water and glycerol binary solvothermal method and their resistivity

Effect of dispersion on visible light transmittance and resistivity of indium tin oxide nanoparticles prepared by cetyltrimethylammonium bromide-assisted coprecipitation method