Electrochemical reduction of the greenhouse gas CO₂ in solid oxide electrolysis cells (SOECs) has attracted much attention due to their high energy conversion efficiency and great potential for carbon cycling. Compared with the asymmetrical configuration, symmetrical SOECs with the same material as anode and cathode, can greatly simplify the fabrication process and reduce the complication associated with varied interfaces. Perovskite oxides La_xSr_2-xFe_1.5Ni_0.1Mo_0.4O_6-δ (L_xSFNM, x=0.1, 0.2, 0.3 and 0.4) are prepared and evaluated as symmetrical electrodes in solid oxide electrolysis cells for electrochemical reduction of pure CO₂. The polarization resistances are 0.07 Ω∙cm² in air and 0.62 Ω∙cm² in 50% CO-50% CO₂ for L_0.3SFNM electrode at 800 ℃. An electrolysis current density of 1.17 A∙cm^-2 under 800 ℃ at 1.5 V is achieved for the symmetrical SOECs in pure CO₂. Furthermore, the symmetrical cell demonstrates excellent stability during the preliminary 50 h CO₂ electrolysis measurements.

Metal-halide perovskite quantum dots (QDs) have emerged as a potential photocatalyst owing to their remarkable optoelectronic properties. However, the poor stability and insufficient charge transportation efficiency of this type of materials hindered their applications in the photocatalysis field. Herein, we decorated CsPbBr₃ QDs on two-dimensional (2D) ultrathin g-C₃N₄ (UCN) nanosheets to develop a 0D/2D CsPbBr₃/UCN composite photocatalyst. The introduction of UCN can not only improve the stability of CsPbBr₃ QDs by passivating the surface ligands of CsPbBr₃ QDs, but also facilitate the charge transfer due to the suited band gap alignment. Consequently, the obtained CsPbBr₃/UCN heterostructure exhibited superior photocatalytic performance to both pristine CsPbBr₃ QDs and UCN. This work has provided an efficient strategy for the design of CsPbX₃-based heterostructure with high stability and photocatalytic activity.

The inherent poor stability of CsPbBr₃ perovskite quantum dots (QDs) is the main impediment restricting their applications. In this work, a CsPbBr₃@TiO₂ core-shell structure nanocomposite with high water stability and efficient photocatalytic activity was fabricated through the hydrolysis of tetrabutyl titanate, followed by calcination. The as-prepared CsPbBr₃ QDs have a size of ca. 8 nm, encapsulated by incompletely crystallized TiO₂ protective layer with a thickness of ca. 20 nm. The photocatalytic performance of the CsPbBr₃@TiO₂ nanocomposite was investigated by degradation of Rhodamine B (RhB) in water under visible light irradiation. The result shows that the CsPbBr₃@TiO₂ nanocomposite exhibits much more enhanced photocatalytic activity than pure TiO₂ and CsPbBr₃ perovskite quantum dots. The photocurrent test results showed that the formation of the CsPbBr₃@TiO₂ heterostructure can promote the separation of photogenerated carriers, which led to the improvement of photocatalytic performance of the composite material. More importantly, TiO₂ can act as a protective layer to separate CsPbBr₃ from water, which brings about the high water stability of the CsPbBr₃@TiO₂ nanocomposite. After photocatalytic degradation of pollutants, the recovered CsPbBr₃@TiO₂ nanocomposite retained its original morphology, luminescent and photocatalytic properties.

High entropy La(Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)O₃ perovskite ceramics powder were prepared using coprecipitation method combined with calcination process, and synthesis temperature of the high entropy perovskite ceramics was significantly reduced. The phases and morphology of the ceramics powder were characterized by different methods. The results show that when the calcination temperature is 800 ℃, perovskite structure with a small amount of second phase was formed in the ceramics powder. When the calcination temperature is 1000 ℃, pure perovskite structure is formed in the La(Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)O₃ high entropy ceramics powder. Three electrode system was used to test the electrical properties of the working electrode made from the La(Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)O₃ high entropy ceramics powder, including cyclic voltammetry (CV) test and constant current charge-discharge (GCD) test. At the current density of 1 A/g, specific capacity of the working electrode reaches 154.8 F/g, while the current density increased to 10 A/g, the electrode material can still maintain 47%(73 F/g) of the initial specific capacity. All results indicate that high entropy La(Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)O₃ perovskite ceramics have good rate properties.

In recent years, perovskite materials become a research hotspot in the field of solar cells due to their excellent photovoltaic properties, but control of their interface defects still remains one of the key problems to be solved. In this study, an organic small molecule additive (L-3-(4-pyridyl)-alanine (PLA)) was introduced in the preparation of perovskite photoabsorption layer by two-step solution method. The characterizations showed that the introduction of PLA could comprehensively improve photoelectric performance of the device, with optimal energy conversion efficiency of 21.53%, in contrast to that of the reference device (20.10%). Further studies showed that PLA could reduce the trap state density of the device from 5.59×10¹⁶cm^-3 to 3.40×10¹⁶cm^-3, promote the interface charge extraction, and decrease the carrier recombination. The above improvements can be attributed to the PLA induced PbI₂ enrichment at grain boundaries and PLA anchoring at defects, which play an important roles in passivate defects. This study can provide guideline for further regulating the defects of perovskite solar cells.

Photostrictive materials exhibit great potential in the light-driven microactuators/sensors, light-controlled microrobots, and other optomechanical applications. In this study, we present the photostrictive performance of Ni-modified Na_0.5Bi_0.5TiO₃-BaTiO₃ (NBT-BT) ceramics prepared by using spark plasma sintering. Under visible light illumination (405, 520 and 655 nm, respectively), the Na_0.5Bi_0.5TiO₃-Ba(Ti_0.5Ni_0.5)O₃ (NBT-BNT) ceramics exhibits large photostriction of the order of 10 ^-3 and photostriction coefficient around 10 ^-11 m ³/W. The XRD peaks of the sample under external illumination show low angle shift, indicating the light-induced lattice distortion, which contributes to the large photostrictive response of NBT-BNT ceramics.

All inorganic perovskite nanocrystals with narrow-emission, high quantum efficiency and high carrier mobility have been widely applied in the fields of light emitting diodes and solar cells. However, present surface ligands of the perovskite nanocrystals are in a dynamic bonding state, which easily fall off during separation and purification processes, resulting in the deterioration of quantum efficiency and stability. Besides, the ionic characteristic of halide perovskites makes it extremely sensitive to polar solvents. These disadvantages severely restrict the practical application of perovskite nanocrystals in optoelectronic devices. In this review, based on the surface state of perovskite nanocrystals, the effects of passivation strategies with Lewis acid, Lewis base and surface coating on optical properties, and stability of CsPbX₃ perovskite nanocrystals are analyzed in detail combined with the domestic and abroad research work. Further optimization and improvement of the stability of CsPbX₃ are prospected.

Owing to high X/γ-ray absorption coefficient, high carrier mobility lifetime product, and low temperature solution growth, halide perovskites emerged as promising room temperature radiation detector materials, which outperform traditional high-purity Ge and CdZnTe materials in term of low-cost, chip compatibility and large-area imaging. Starting from the fundamental properties of halide perovskites and the principle of radiation detectors, the development of halide perovskite radiation detectors since 2015 was briefly introduced. Then, recent progresses of direct radiation detectors (intensity, imaging, energy spectroscopy) and indirect scintillator detectors were systematically reviewed, and the crucial factors for high-performance detectors were discussed, which could provide valuable guidance for further boosting performance of halide-perovskite-based radiation detectors in future.

Electron transport layer is a key part for perovskite solar cell (PSC), which can block holes and transmit electrons to reduce recombination. In this study, SnO₂ was synthesized with low-temperature solution-processed method and used as electronic transport layer for perovskite solar cells. The influence of annealing temperature on the properties of SnO₂ films and PSCs were systematically studied. The results showed that with the annealing temperatures at 60, 90, 120, 240 ℃, the surfaces of SnO₂ films own more pores; while annealed at 150, 180, 210 ℃, the corresponding surfaces show fewer pores. It was found that the transmittance of FTO glass covered with SnO₂ films is better than that of the bare FTO glass. With SnO₂ annealed at 180 ℃, the electron mobility of the thin film is the highest. The corresponding PSC possesses the best transmission resistance, composite resistance, and superior photovoltaic performance. The photoelectric conversion efficiency, the open-circuit voltage, the short-circuit current and the filling factor were 17.28%, 1.09 V, 20.91 mA/cm² and 75.91%, respectively.

Lanthanum-substituted La_xSr_2-3x/2Fe_1.5Ni_0.1Mo_0.4O_6-δ (La_xSFNM, x=0, 0.1, 0.2, 0.3, 0.4) oxides were synthesized by the solid-state reaction method, and investigated as potential anodes for Solid Oxide Fuel Cells(SOFC). X-ray diffraction patterns of as-synthesized powders confirm the formation of the cubic perovskite structure. Reduction in H₂ promotes the segregation of nano-scale metallic Fe-Ni alloy particles on the grain surfaces. Scanning electron microscopy observations indicate that increasing La ³⁺ dopants results in a decrease in the density of the exsolved nanoparticulates. Based upon impedance measurements on symmetrical fuel cells, the anode polarization resistance decreases with the La ³⁺ dopant increasing, and attains a minimal value of 0.16 W?cm ² for La_0.3SFNM at 750 ℃, followed by a slight increase to 0.17 W?cm ² for La_0.4SFNM. The highest catalytic activity of La_0.3SFNM toward electro- oxidation of hydrogen fuels could be ascribed to the synergy between the exsolved Fe-Ni alloy nanoparticulates and the supporting La_xSFNM oxides. Thin La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM) electrolyte fuel cells with La_0.3SFNM anodes and SmBa_0.5Sr_0.5Co₂O₆ cathodes exhibit the highest power densities, e.g., 1.26, 0.90 and 0.52 W?cm ^-2 at 750, 650 and 550 ℃, respectively. These results demonstrate La_0.3SFNM oxide as a promising high performance SOFC anode.