A review on molten salt synthesis of metal oxide nanomaterials: Status, opportunity, and challenge

2D filler-reinforced polymer nanocomposite dielectrics for high-k dielectric and energy storage applications

A wide range of inorganic nanomaterials with many fascinating properties and application potentials in widespread fields may be synthesized by wet chemical synthetic routes. To achieve scientific a...

Recent Developments on Molten Salt Synthesis of Inorganic Nanomaterials: A Review

New non-volatile memories are being investigated to keep up with the organic-electronics road map. Ferroelectric polarization is an attractive physical property as the mechanism for non-volatile switching, because the two polarizations can be used as two binary levels. However, in ferroelectric capacitors the read-out of the polarization charge is destructive. The functionality of the targeted memory should be based on resistive switching. In inorganic ferroelectrics conductivity and ferroelectricity cannot be tuned independently. The challenge is to develop a storage medium in which the favourable properties of ferroelectrics such as bistability and non-volatility can be combined with the beneficial properties provided by semiconductors such as conductivity and rectification. Here we present an integrated solution by blending semiconducting and ferroelectric polymers into phase-separated networks. The polarization field of the ferroelectric modulates the injection barrier at the semiconductor-metal contact. The combination of ferroelectric bistability with (semi)conductivity and rectification allows for solution-processed non-volatile memory arrays with a simple cross-bar architecture that can be read out non-destructively. The concept of an electrically tunable injection barrier as presented here is general and can be applied to other electronic devices such as light-emitting diodes with an integrated on/off switch.

http://absimage.aps.org/image/MAR09/MWS_MAR09-2008-020293.pdf

Organic non-volatile memories from ferroelectric phase separated blends

BaZnSi 3 O 8 ceramic was prepared via the conventional solid-state method and sintered at 1100 °C. XRD and synchrotron Rietveld refinement analyses revealed the BaZnSi 3 O 8 ceramic presented monoclinic structure with a space group of P 2 1 /a (No.14), which was reported for the first time. The BaZnSi 3 O 8 ceramic presented a weak ferroelectricity, which was confirmed by the P-E loop and the 90° nanoscale ferroelectric domain. Although e r - T displayed two e r abnormal peaks at 400 °C and 460 °C, the Curie temperature ( T - c ) was located at 460 °C according to the dielectric loss and Curie-Weiss law. Moreover, the BaZnSi 3 O 8 ceramic exhibited optimised microwave dielectric properties with e r = 6.55, Q × f = 52400 GHz, and τ f = -24.5 ppm/°C. Hence, the BaZnSi 3 O 8 ceramic in the ternary BaO-ZnO-SiO 2 system possessed both weak ferroelectricity and microwave dielectric properties. These results are expected to break the technical barrier of ferroelectric phase shifter applications in microwave and even millimeter-wave frequency bands.

Crystal Structure and Ferroelectric Evidence of BaZnSi3O8, a Low‐Permittivity Microwave Dielectric Ceramic

Ferroelectrics are a class of functional materials that have spontaneous polarization and whose direction can be modulated by external electric fields. The improvement of the electrical properties of ferroelectrics is closely related to the control of their crystal structure and morphology. The molten salt method is a chemical synthesis method in which a molten salt functions as a high-temperature liquid solvent. The special molten salt reaction environment is conducive to the dissolution of raw materials, the transport of reactants, and the directional assembly of basic units to prepare scale- and shape-controllable target materials. In particular, ferroelectrics synthesized by the molten salt method have a variety of technical advantages, such as controllable morphology (0D, 1D and 2D), high dielectric constant, high piezoelectric performance, and strong sintering activity. Therefore, ferroelectrics synthesized by this process have been used in important applications in the energy field in different forms, such as single crystals, textured ceramics, piezoelectric composites, oriented composites, multilayer composites and ferroelectric ceramics. This review article highlights the critical issues and the recent progress of molten salt preparation of ferroelectrics and their application from the viewpoint of synthesis strategies, reaction mechanisms, and energy device assembly. It is anticipated that this review can serve as an overview and evaluation of the state-of-the-art molten salt synthesis of ferroelectrics and their design for applications in energy conversion and energy storage devices.

Xuepeng Liu

Papers

A construction strategy of ferroelectrics by the molten salt method and its application in the energy field