As an effective method to improve the optical properties and stability of perovskite matrix, doped halide perovskites have attracted extensive attention in the field of optoelectronic applications. Herein, a series of all inorganic lead-free Te4+-doped Cs2ZrCl6 vacancy-ordered perovskites were successfully synthesized with different Te-doping concentrations by a solvothermal method, and deliberate Te4+-doping results in green-yellow triplet self-trapped exciton (STE) emission with a high photoluminescence quantum yield (PLQY) of 49.0%. The efficient energy transfer was observed from singlet to triplet emission. Further, the effects of A-site Rb alloying on the optical properties and stability were investigated. We found that A-site Rb alloying and C-site cohalogenation did not change the luminescence properties of Te4+, but the addition of a small amount of Rb+ can improve the PL intensity and moisture stability. Our results provide physical insights into the nS2 Te4+-ion-doping-induced emissive mechanism and shed light on improving the environmental stability for further applications.

Efficient Energy Transfer in Te4+-Doped Cs2ZrCl6 Vacancy-Ordered Perovskites and Ultrahigh Moisture Stability via A-Site Rb-Alloying Strategy.

As global warming, energy shortages, and environment pollution have intensified, low-carbon and energy-saving lighting technology has attracted great attention worldwide. Light emitting diodes (LED...

Perovskite White Light Emitting Diodes: Progress, Challenges, and Opportunities.

Metal halide perovskites are promising semiconductors for next-generation light-emitting diodes (LEDs) due to their high luminance, excellent color purity, and handily tunable band gap. However, it remains a great challenge to develop perovskite LEDs (PeLEDs) with pure red emission at the wavelength of 630 nm. Herein, we report a spectrally stable and efficient pure red PeLED by employing sequential ligand post-treated CsPbI3 quantum dots (QDs). The synthesized CsPbI3 QDs with a size of ∼5 nm are treated in sequential steps using the ligands of 1-hydroxy-3-phenylpropan-2-aminium iodide (HPAI) and tributylsulfonium iodide (TBSI), respectively. The CsPbI3 QD films exhibit improved optoelectronic properties, which enables the fabrication of a pure red PeLED with a peak external quantum efficiency (EQE) of 6.4% and a stable EL emission centered at the wavelength of 630 nm. Our reported sequential ligand post-treatment strategy opens a new route to improve the stability and efficiency of PeLEDs based on QDs.

Spectrally Stable and Efficient Pure Red CsPbI3 Quantum Dot Light-Emitting Diodes Enabled by Sequential Ligand Post-Treatment Strategy.

Halide perovskites are considered to be next-generation semiconductor materials with bright prospects to advance the technology of photonics and optoelectronics. Because of the intrinsic ionic feature, the interactions between perovskites and water induce serious stability issues, which has been one of the fundamental problems hindering the practical application of perovskites. The degradation of halide perovskites upon water exposure has been intensively studied, resulting in chemical insights into key processes, including hydration, phase transformation, decomposition, and dissolution. In this Perspective, we try to illustrate what happens when halide perovskites meet with water. We summarize the research progress regarding the understanding of these processes and discuss the principle of strategy design toward improved stability against water. In addition to the instability-related interactions, we also discuss the aqueous solution of perovskite precursors for fabricating perovskite-based functional materials. Hopefully, this Perspective can inspire more fundamental studies on the interactions between perovskites and water, such as spectroscopy and simulation, crystal structure and material characterizations, and solution chemistry and crystallization.

What Happens When Halide Perovskites Meet with Water?

Perovskite quantum dots have been attractive building blocks for novel photonic devices development, where patterning is usually one of the most critical steps. We report on the combination of in s...

In Situ Patterning Perovskite Quantum Dots by Direct Laser Writing Fabrication

Highly Stable and Spectrally Tunable Gamma Phase RbxCs1–xPbI3 Gradient‐Alloyed Quantum Dots in PMMA Matrix through A Sites Engineering

One‐Step Polymeric Melt Encapsulation Method to Prepare CsPbBr3 Perovskite Quantum Dots/Polymethyl Methacrylate Composite with High Performance

Comparison of low-temperature catalytic activity and H2O/SO2 resistance of the Ce-Mn/TiO2 NH3-SCR catalysts prepared by the reverse co-precipitation, co-precipitation and impregnation method

The fluoride with high-concentration in industrial wastewater will cause great harm to the environment and calcium-modified biochar is an effective adsorbent for the removal of fluoride. Biochar composites were prepared from mature and dried dead leaves and eggshell to remove fluoride from the aqueous solution. The effects of raw material ratio, pH, contact time, adsorbent dosage, temperature, initial concentration of fluoride, and the coexisting ions on the removal efficiency of fluoride were explored. The biochar composites before and after fluoride removal were characterized by the SEM, FTIR, XRD, and XPS, which showed CaF2 precipitation was formed during the adsorption. The kinetics and isotherm study showed that chemical adsorption was the primary step for the fluoride adsorption of the biochar composites. The removal efficiency of fluoride can reach 98.53% when the amount of adsorbent was 1.6 g/L and the fluoride concentration was 500 mg/L. The BET-specific surface area of platanus acerifoli leaves biochar was 410.14 m2/g, which was suitable for the adsorption carrier. The adsorption capacity of the biochar composite materials was as high as 308 mg/g. The platanus acerifoli leaves-eggshell biochar composite with large pore size and high removal efficiency may be used as an efficient and low-cost adsorbent for treating high-concentration fluoride-containing wastewater.

Huidong Xie

Papers

Highly Stable and Spectrally Tunable Gamma Phase RbxCs1–xPbI3 Gradient‐Alloyed Quantum Dots in PMMA Matrix through A Sites Engineering

One‐Step Polymeric Melt Encapsulation Method to Prepare CsPbBr3 Perovskite Quantum Dots/Polymethyl Methacrylate Composite with High Performance

Comparison of low-temperature catalytic activity and H2O/SO2 resistance of the Ce-Mn/TiO2 NH3-SCR catalysts prepared by the reverse co-precipitation, co-precipitation and impregnation method

Removal of fluoride using platanus acerifoli leaves biochar - an efficient and low-cost application in wastewater treatment.