Surface Engineering of 2D Metal-Porphyrin Metal-Organic Frameworks Z-Scheme Heterostructure for Boosting and Stable Photocatalytic Hydrogen Evolution.

How to improve the stability and activity of metal-organic frameworks is an attractive but challenging task in energy conversion and pollutant degradation of metal-organic frameworks materials. In this paper, we developed a facile method by fabricating TiO nanoparticles (NPs) layer on 2D copper tetracarboxylphenyl-metalloporphyrin metal-organic frameworks (MOFs) with Zn2+ as the linkers (ZnTCuMT-X, "Zn" represented Zn2+ as the linkers, the first "T" represented tetracarboxylphenyl-metalloporphyrin (TCPP), "Cu" represented the Cu2+ coordinated into the porphyrin macrocycle, "M" represented MOFs, the second "T" represented TiO NPs layer, and "X" represented the added volume of n-tetrabutyl titanate (X = 100, 200, 300 or 400)). It was found that the optimized ZnTCuMT-200 showed greatly and stably enhanced H2 generation, which was about 28.

Strategy for Highly Efficient Detection and Removal of Raman Inactive Leuco-Malachite Green on Environmentally Friendly Graphitic Carbon Nitride-Based Nanostructures.

The sustainable identification and efficient degradation of some recessive and seriously toxic pollutants are important issues in practical applications. Herein, a portable platform (EAl/ACN/Ag) constructed by growing AgNPs in situ in the cavities of the alkalized carbon nitride (ACN) coated on the etched Al sheet (EAl) is achieved. Interestingly, on the constructed EAl/ACN/Ag substrate irradiated by light for 3 min, a Raman inactive leuco-malachite green (LMG: a highly toxic and environmentally persistent pollutant that is difficult to be found due to being colorless) can be sensitively and selectively detected by surface-enhanced Raman scattering spectroscopy (SERS).

Selective surface enhanced Raman detection and effective photocatalytic degradation of sulfonamides antibiotic based on a flexible three-dimensional chitosan/carbon nitride/silver substrate.

The prevalence of sulfonamide residues in aquatic environments poses serious environmental risks, and the sensitive detection and effective degradation of sulfonamides have attracted widespread attention. Here, the environmentally friendly chitosan (CS)/carbon nitride (CN) with three-dimensional porous structure is fabricated by freeze-drying method, and subsequently a new bifunctional flexible substrate (CS/CN/Ag) is prepared by anchoring of small sized AgNPs (6 ∼ 12 nm) on CS/CN. Importantly, the CS/CN/Ag substrate shows high adsorption capacity (∼ 83.

Lattice disorder influences the photocarrier dynamics in lead halide perovskites.

Revealing the structural impact of lead halide perovskites on photocarrier dynamics is essential for the associated solar cells but deficient in experimental visualization. In this study, with femtosecond spectroscopy, we for the first time explored the contribution of the disorder of the distorted PbX octahedrons and A-site cations on the carrier behaviours. It was found that photoinduced carriers recombine almost twice slower and diffuse 20% faster in the disordered, β-phased samples than in the ordered, γ-phased ones.

The durability of resin-dentine bonds are enhanced by epigallocatechin-3-gallate-encapsulated nanohydroxyapatite/mesoporous silica.

Biomimetic nanohydroxyapatite (nHAp) has long been used as a biocompatible material for bone repair, bone regeneration, and bone reconstruction due to its low toxicity to local or systemic tissues. Various cross-linkers have been employed to maintain the structure of collagen; these include epigallocatechin-3-gallate (EGCG), which can fortify the mechanical properties of collagen and withstand the degradation of collagenase. We hypothesized that EGCG combined with nHAp may promote resin-dentin bonding durability.

A portable architectonics of Al/carbon nitride/metal-organic frameworks anchored Ag nanoparticles for SERS detection and photocatalytic degradation of fungicide.

In recent years, it is urgent to develop bi-functional materials for highly sensitive SERS detection and photocatalytic degradation of contaminants in water of fish pond. Herein, using 5-mercapto-1-methyltetrazole as the ligand, the tree-trunk like zeolitic imidazolate framework (ZIF-8) is induced and in-situ grown on the surface of aluminum/flower carbon nitride (Al/f-CN). Then, AgNPs are tightly anchored in ZIF-8 of Al/f-CN/ZIF-8 by strong Ag-N and Ag-S bonds, and a portable architecture of Al/f-CN/ZIF-8/Ag is successfully prepared.

Solution chemistry quasi-epitaxial growth of atomic CaTiO perovskite layers to stabilize and passivate TiO photoelectrodes for efficient water splitting.

Perovskite oxides with unique crystal structures and high defect tolerance are promising as atomic surface passivation layers for photoelectrodes for efficient and stable water splitting. However, controllably depositing and crystalizing perovskite-type metal oxides at the atomic level remains challenging, as they usually crystalize at higher temperatures than regular metal oxides. Here, we report a mild solution chemistry approach for the quasi-epitaxial growth of an atomic CaTiO perovskite layer on rutile TiO nanorod arrays.

Procyanidin B2 inhibits angiogenesis and cell growth in oral squamous cell carcinoma cells through the vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) pathway.

This study aimed to explore the therapy role of procyanidin B2 (PB2) in inhibiting angiogenesis and cell growth in oral squamous cell carcinoma. After oral mucosa epithelial cell (OMEC) and human oral squamous cell carcinoma (OSCC) cell line (SCC-25) were treated with PB2 or SCC-25 were treated with PB2 and rhVEGF, cell counting kit-8 (CCK-8) assay was used to determine the cell viability. The apoptosis, migration, invasion and angiogenesis of SCC-25 after indicated treatment were detected by Tunel, wound healing, transwell and tube formation assays.

Deep-Red Perovskite Light-Emitting Diodes Based on One-Step-Formed γ-CsPbI Cuboid Crystallites.

Inorganic CsPbI perovskite with high chemical stability is attractive for efficient deep-red perovskite light-emitting diodes (PeLEDs) with high color purity. Compared to PeLEDs based on ex-situ-synthesized CsPbI nanocrystals/quantum dots suffering from low conductivity and efficiency droop under high current densities, in situ deposited 3D CsPbI films from precursor solutions can maintain high conductivity but show high trap density. Here, it is demonstrated that introducing diammonium iodide can increase the size of colloids in the precursor solution, retard the phase-transition rate, and passivate trap states of the in-situ-formed cuboid crystallites.

MA Cation-Induced Diffusional Growth of Low-Bandgap FA-Cs Perovskites Driven by Natural Gradient Annealing.

Low-bandgap formamidinium-cesium (FA-Cs) perovskites of FA Cs PbI ( < 0.1) are promising candidates for efficient and robust perovskite solar cells, but their black-phase crystallization is very sensitive to annealing temperature. Unfortunately, the low heat conductivity of the glass substrate builds up a temperature gradient within from bottom to top and makes the initial annealing temperature of the perovskite film lower than the black-phase crystallization point (~150°C).

Organic Tetrabutylammonium Cation Intercalation to Heal Inorganic CsPbI Perovskite.

The in situ formation of reduced dimensional perovskite layer via post-synthesis ion exchange has been an effective way of passivating organic-inorganic hybrid perovskites. In contrast, cesium ions in Cs-based inorganic perovskite with strong ionic binding energy cannot exchange with those well-known organic cations to form reduced dimensional perovskite. Herein, we demonstrate that tetrabutylammonium (TBA ) cation can intercalate into CsPbI to effectively substitute the Cs cation and to form one-dimensional (1D) TBAPbI layer in the post-synthesis TBAI treatment.

Chemically Stable Black Phase CsPbI Inorganic Perovskites for High-Efficiency Photovoltaics.

Research on chemically stable inorganic perovskites has achieved rapid progress in terms of high efficiency exceeding 19% and high thermal stabilities, making it one of the most promising candidates for thermodynamically stable and high-efficiency perovskite solar cells. Among those inorganic perovskites, CsPbI with good chemical components stability possesses the suitable bandgap (≈1.7 eV) for single-junction and tandem solar cells.

5-Ammonium Valeric Acid Iodide to Stabilize MAPbI via a Mixed-Cation Perovskite with Reduced Dimension.

5-Ammonium valeric acid iodide (AVAI) has been widely known as a stabilizer to enhance the stability of MAPbI perovskite, but its role and function is still under exploration. The typical 2D perovskites of AVAPbI have been proposed as the capping layer for stabilization. Here, a novel AVA-MA mixed-cation perovskite of AVAMAPbI is found to show a more even and compact coverage than the typical 2D perovskite of AVAPbI.

Organic salt mediated growth of phase pure and stable all-inorganic CsPbX (X = I, Br) perovskites for efficient photovoltaics.

All-inorganic CsPbX (X = I, Br) perovskites without organic component are promising for long-term stability but face main challenges of facile fabrication and phase stability. Here we discover a general organic methylamine acetate salt mediated growth method to deposit high quality phase pure and stable CsPbX (X = I, Br) perovskite films via a novel precursor consisting of stoichiometric cesium acetate (CsAc), methylamine halide (MAX) and lead halide (PbX). Interestingly, these organic salts of CsAc and MAX could efficiently promote the crystallization process especially lower the crystallization temperature, but do not introduce the incorporation of organic MA cation into all-inorganic CsPbX perovskites.

Spontaneous low-temperature crystallization of α-FAPbI for highly efficient perovskite solar cells.

Formamidinium lead triiodide (HC(NH)PbI or FAPbI) is a promising light absorber for high-efficiency perovskite solar cells because of its superior light absorption range and thermal stability to CHNHPbI (MAPbI). Unfortunately, it is difficult to fabricate high-quality FAPbI thin films to surpass the MAPbI-based cells due to easily forming unwanted but more stable yellow δ-phase and thus requiring high annealing-temperature for wanted photovoltaic-active black α-phase. Herein, we reported a novel low-temperature fabrication of highly crystallized α-FAPbI film exhibiting uniaxial-oriented nature with large grain sizes up to 2 μm.

Steric Mixed-Cation 2D Perovskite as a Methylammonium Locker to Stabilize MAPbI.

The reduced dimension perovskite including 2D perovskites are one of the most promising strategies to stabilize lead halide perovskite. A mixed-cation 2D perovskite based on a steric phenyltrimethylammonium (PTA) cation is presented. The PTA-MA mixed-cation 2D perovskite of PTAMAPbI can be formed on the surface of MAPbI (PTAI-MAPbI ) by controllable PTAI intercalation by either spin coating or soaking.

The Role of Dimethylammonium Iodide in CsPbI Perovskite Fabrication: Additive or Dopant?

The controllable growth of CsPbI perovskite thin films with desired crystal phase and morphology is crucial for the development of high efficiency inorganic perovskite solar cells (PSCs). The role of dimethylammonium iodide (DMAI) used in CsPbI perovskite fabrication was carefully investigated. We demonstrated that the DMAI is an effective volatile additive to manipulate the crystallization process of CsPbI inorganic perovskite films with different crystal phases and morphologies.

Thermodynamically stabilized β-CsPbI-based perovskite solar cells with efficiencies >18.

Although β-CsPbI has a bandgap favorable for application in tandem solar cells, depositing and stabilizing β-CsPbI experimentally has remained a challenge. We obtained highly crystalline β-CsPbI films with an extended spectral response and enhanced phase stability. Synchrotron-based x-ray scattering revealed the presence of highly oriented β-CsPbI grains, and sensitive elemental analyses-including inductively coupled plasma mass spectrometry and time-of-flight secondary ion mass spectrometry-confirmed their all-inorganic composition.

Fast Charge Diffusion in MAPb(IBr ) Films for High-Efficiency Solar Cells Revealed by Ultrafast Time-Resolved Reflectivity.

Organometallic halide perovskite solar cells such as MAPbI have shown great promise as a low-cost, high-efficiency photovoltaic candidate. Recent studies demonstrated that by substituting an appropriate amount I ions of MAPbI with Br ions, the device performance parameters, such as moisture stability or power conversion efficiency, can be further optimized. In this study, using time-resolved optical reflectivity to track the carrier dynamics in MAPb(IBr ) films with different Br contents, we found that photocarriers in MAPb(IBr ) films with x = 0.

Bifunctional Stabilization of All-Inorganic α-CsPbI Perovskite for 17% Efficiency Photovoltaics.

The all-inorganic α-CsPbI perovskite with the most suitable band gap faces serious challenges of low phase stability and high moisture sensitivity. We discover that a simple phenyltrimethylammonium bromide (PTABr) post-treatment could achieve a bifunctional stabilization including both gradient Br doping (or alloying) and surface passivation. The PTABr treatment on CsPbI only induces less than 5 nm blue shift in UV-vis absorbance but significantly stabilize the perovskite phase with much better stability.

Optoelectronic Dichotomy of Mixed Halide CHNHPb(BrCl ) Single Crystals: Surface versus Bulk Photoluminescence.

In this work, the spatially dependent recombination kinetics of mixed-halide hybrid perovskite CHNHPb(BrCl ) (0 ≤ x ≤ 0.19) single crystals are investigated using time-resolved photoluminescence spectroscopy with one- and two-photon femtosecond laser excitation. The introduction of chloride by substituting a fraction of the bromide leads to a decreased lattice constant compared to pure bromide perovskite ( x = 0) and a higher concentration of surface defects.

Li dopant induces moisture sensitive phase degradation of an all-inorganic CsPbIBr perovskite.

All-inorganic halide perovskites without volatile components have great potential for long term thermal stability. However, the phase stability of all-inorganic perovskites is sensitive to moisture and has been seldom studied. In this work, the phase stability of α-CsPbI2Br was studied in different relative humidity conditions.

Bication lead iodide 2D perovskite component to stabilize inorganic α-CsPbI perovskite phase for high-efficiency solar cells.

Among various all-inorganic halide perovskites exhibiting better stability than organic-inorganic halide perovskites, α-CsPbI with the most suitable band gap for tandem solar cell application faces an issue of phase instability under ambient conditions. We discovered that a small amount of two-dimensional (2D) EDAPbI perovskite containing the ethylenediamine (EDA) cation stabilizes the α-CsPbI to avoid the undesirable formation of the nonperovskite δ phase. Moreover, not only the 2D perovskite of EDAPbI facilitate the formation of α-CsPbI perovskite films exhibiting high phase stability at room temperature for months and at 100°C for >150 hours but also the α-CsPbI perovskite solar cells (PSCs) display highly reproducible efficiency of 11.

Synergetic Effect of Chloride Doping and CH NH PbCl on CH NH PbI Cl Perovskite-Based Solar Cells.

The chloride-doped CH NH PbI Cl perovskite has attracted great attention owing to clear performance enhancement by using a Cl additive and by the controversial arguments on Cl function and the mechanism behind it. Herein, a series of CH NH PbI Cl perovskites with various Cl content was prepared through a gas/solid reaction between CH NH gas and HPbI Cl (x=0-1). The small amount of Cl doping in CH NH PbI Cl (x=0.

Ion-Exchange-Induced 2D-3D Conversion of HMA FA PbI Cl Perovskite into a High-Quality MA FA PbI Perovskite.

High-quality phase-pure MA FA PbI planar films (MA=methylammonium, FA=formamidinium) with extended absorption and enhanced thermal stability are difficult to deposit by regular simple solution chemistry approaches owing to crystallization competition between the easy-to-crystallize but unwanted δ-FAPbI /MAPbI and FA MA PbI requiring rigid crystallization conditions. Here A 2D-3D conversion to transform compact 2D mixed composition HMA FA PbI Cl perovskite precursor films into 3D MA FA PbI (x=0.1-0.