Using electrochemical etching of a polycrystalline 3C-SiC target and subsequent ultrasonic treatment in water solution, we have fabricated suspensions of 3C-SiC nanocrystallites that luminesce. Transmission electron microscope observations show that the 3C-SiC nanocrystallites, which uniformly disperse in water, have sizes in the range of 1-6 nm. Photoluminescence and photoluminescence excitation spectral examinations show clear evidence for the quantum confinement of 3C-SiC nanocrystallites with the emission band maximum ranging from 440 to 560 nm. Tunable, composite polystyrene/SiC film can be made by adding polystyrene to a toluene suspension of the 3C-SiC nanocrystallites and then coating the resulting solution onto a Si wafer.

We have proved that Cs2SnI6−xBrx (x = 0–6) can be eutectic in the whole composition, and the eutectic phase has the similar cubic symmetry with both of the end phases (space group of Fm3¯m). The lattice constant decreases from around 11.67 Å (x = 0) to around 10.83 Å (x = 6). Hall-plot analysis shows that the strain varies sharply near the two end materials, while the strain is almost independent of Br content at the middle Br content. The bandgap, on the other hand, increases from 1.26 eV to 2.93 eV with increasing the Br content, which might be expected in fabricating the continuous junction solar cells.

Inorganic perovskite CsPbBr3 is a material used for fabricating highly efficient and stable perovskite solar cells. In this work, a two-step infiltration-spinning method is proposed to obtain CsPbBr3 films with pure phase. Phase transformations between CsPb2Br5, CsPbBr3 and Cs4PbBr6 are investigated by controlling the contact time between the CsBr solution and the PbBr2 substrate. CsPbBr3 films with large grain sizes are obtained after high temperature post-treatment. The CsPbBr3-based solar cells show a high efficiency (approximately 7%) with a short-circuit current density of 6.68 mA cm−2, an open-circuit voltage of 1.47 V and a fill factor of 70.9% under standard solar illumination.

In this report, we discuss the 22% efficiency improvement of solar cells based on the MAPbI3 perovskite film extracted with a mixed anti-solvent. The film quality of MAPbI3 extracted from the mixed anti-solvent of ether and isopropanol is improved greatly. The average grain size of the film may be enlarged twice. We argue that some solvents residing in the precursor may effectively promote the crystallization process of MAPbI3 to form large grains. We believe that this study may open a method to fabricate high-quality MAPbI3 perovskite films for highly efficient solar cells.

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We obtained one new molecular ferroelectric material tris(2-hydroxyethyl) ammonium bromide (TAB) that crystallizes in aqueous solution at room temperature with a space group of R3m which belongs to ten polar space groups. There is a paraelectric-toferroelectric phase transition at 424 K (from hexagonal R3̅ m to hexagonal R3m phase). Such a high transition temperature is close to that of diisopropylamine bromide (426 K) and higher than that of many other molecular ferroelectrics, such as triethylmethylammonium tetrabromoferrate(III) (360 K); some of the organic−inorganic perovskite ferroelectrics, such as (cyclohexylammonium) 2 PbBr 4 (363 K); and some inorganic ferroelectrics, including BaTiO 3 (393 K). The saturated polarization and the coercive field of TAB measured from the ferroelectric hysteresis loop are about 0.54 μC•cm −2 and 0.62 kV/cm, respectively. Given its superior performance, including high phase transition temperature, room-temperature ferroelectricity, small coercive electric field, and adjustable ladder-shaped dielectric constant, TAB will have many potential applications.

Organic–inorganic hybrid materials are easy to modify, which makes it possible to construct multifunctional ferroelectrics directionally and apply the built-in electric field and switching properties of ferroelectrics to multidisciplinary fields. Particularly, the coupling of photoluminescence and ferroelectricity in a single hybrid material facilitates its novel applications in lighting sensors, memory devices, and other multifunctional applications. Based on the photoluminescent molecule 4-(2-aminoethyl) morpholine (AEM), here, a room-temperature ferroelectric (C6H16N2O)CdBr4·H2O (AEM-CdBr 4 ) is designed and obtained, which crystallizes in a polar orthorhombic space group of Pca21. A reversible ferroelectric–paraelectric phase transition was confirmed at 353 K through experimental results, such as differential scanning calorimetry (DSC) curves, variable-temperature Raman spectroscopy, and photoluminescence (PL) spectroscopy. The crystal exhibits ferroelectricity at room temperature with a saturation polarization of approximately 8 μC/cm2. The photoluminescence of compound AEM-CdBr 4 is mainly derived from the monomeric fluorescence emission of the AEM molecule and is not directly related to the energy band structure of the crystal. This room-temperature molecular-type ferroelectric AEM-CdBr 4 with photoluminescence will provide new ideas for the design of new multifunctional ferroelectrics.

An immediate quenching using liquid N2 is applied for synthesizing the 5d transition-metal oxides (Sr1-xCax)2IrO4 (0 ≤ x ≤ 0.15) single phase. X-ray diffraction together with Rietveld refinement shows that the lattice parameters along a and c directions and the bond angle of Ir-O2-Ir decrease with the increase of Ca content. X-ray Absorption Fine Spectroscopy measurements prove that the valence of Ir and the average Ir-O bond-length substantially remain unchanged with Ca content increasing in the phase. The effective magnetic moment μeff and Néel temperature TN decrease simultaneously with increased Ca content. Electrical resistivity shows complex temperature dependence behavior, which follows the three-dimensional variable range hopping behavior at low temperature, Arrhenius-type behavior at middle-temperature, and a weak electronic localization in quasi-two-dimensional at high temperature.