Long-Term Corrosion of Eutectic Gallium, Indium, and Tin (EGaInSn) Interfacing with Diamond.

Thermal transport is of grave importance in many high-value applications. Heat dissipation can be improved by utilizing liquid metals as thermal interface materials. Yet, liquid metals exhibit corrosivity towards many metals used for heat sinks, such as aluminum, and other electrical devices (i.e., copper). The compatibility of the liquid metal with the heat sink or device material as well as its long-term stability are important performance variables for thermal management systems. Herein, the compatibility of the liquid metal Galinstan, a eutectic alloy of gallium, indium, and tin, with diamond coatings and the stability of the liquid metal in this environment are scrutinized. The liquid metal did not penetrate the diamond coating nor corrode it. However, the liquid metal solidified with the progression of time, starting from the second year. After 4 years of aging, the liquid metal on all samples solidified, which cannot be explained by the dissolution of aluminum from the titanium alloy. In contrast, the solidification arose from oxidation by oxygen, followed by hydrolysis to GaOOH due to the humidity in the air. The hydrolysis led to dealloying, where In and Sn remained an alloy while Ga separated as GaOOH. This hydrolysis has implications for many devices based on gallium alloys and should be considered during the design phase of liquid metal-enabled products.

RbPbI3 Seed Embedding in PbI2 Substrate Tailors the Facet Orientation and Crystallization Kinetics of Perovskites.

High power conversion efficiencies (PCEs) in perovskite solar cells (PSCs) have always been awe-inspiring, but perovskite films scalability is an exacting precondition for PSCs commercial deployment, generally unachievable through the antisolvent technique. On the contrary, in the two-step sequential method, the perovskite's uncontrolled crystallization and unnecessary PbI2 residue impede the device's performance. These two issues motivated to empower the PbI2 substrate with orthorhombic RbPbI3 crystal seeds, which act as grown nuclei and develop orientated perovskites lattice stacks, improving the perovskite films morphologically and reducing the PbI2 content in eventual perovskite films. Thence, achieving a PCE of 24.17% with suppressed voltage losses and an impressive life span of 1140 h in the open air.

Defect recombination suppression and carrier extraction improvement for efficient CsPbBr3/SnO2heterojunction photodetectors.

Perovskite materials with excellent optical and electronic properties have huge potential in the research field of photodetectors. Constructing heterojunctions and promoting carrier transportation are significant for the development of perovskite-based optoelectronics devices with high performances. Herein, we demonstrated a CsPbBr3/SnO2heterojunction photodetector and improved the device performances through post-annealing treatment of SnO2film. The results indicated that the electrical properties of SnO2films will make an important impact on carrier extraction, especially for type-II heterojunction. As the electrons transfer layer in CsPbBr3/SnO2type-II heterojunction, defects related to oxygen vacancy should be the key factor to affect carrier concentration, induce carriers' limitation and recombination rate. Under proper annealing temperature for SnO2layer, the recombination rate can decrease to 1.37 × 1021cm3s and the spectral responsivity will be highly increased. This work can enhance the understanding on the photoresponse of perovskite photodetectors, and will be helpful for the further optimization and design of optoelectronic devices based on the perovskite heterojunction.

A simple and feasible fluorescent approach for rapid detection of hexavalent chromium based on gold nanoclusters.

Hexavalent chromium (Cr6+) owns hypertoxicity, non-biodegradability, and carcinogenicity, thus the detection of Cr6+ is of paramount significance for environmental monitoring and human health maintenance. Herein, a simple, rapid, and feasible fluorescent method based on gold nanoclusters (AuNCs) was established for determination of Cr6+. The AuNCs was coated by a simple and fast one-pot method using d-histidine (d-His) and polylysine (P-Lys) as stabilizers and reductants, which could be quenched by the addition of Cr6+ owing to the aggregation of AuNCs and fluorescence resonance energy transfer (FRET) between AuNCs and Cr6+. Under the optimal conditions, the fluorescent sensor exhibited good linearity within 10-10000 µg/L with limit of detection of 7.2 µg/L. The developed sensor possessed favorable sensitivity and selectivity. Additionally, the proposed method also had favorable recovery with good precision and accuracy within the actual sample, including celery cabbage, rice, capsule shell, and river water.

Porous BiVO4/Boron-Doped Diamond Heterojunction Photoanode with Enhanced Photoelectrochemical Activity.

Constructing heterojunction is an attractive strategy for promoting photoelectrochemical (PEC) performance in water splitting and organic pollutant degradation. Herein, a novel porous BiVO4/Boron-doped Diamond (BiVO4/BDD) heterojunction photoanode containing masses of ultra-micro electrodes was successfully fabricated with an n-type BiVO4 film coated on a p-type BDD substrate by magnetron sputtering (MS). The surface structures of BiVO4 could be adjusted by changing the duration of deposition (Td). The morphologies, phase structures, electronic structures, and chemical compositions of the photoanodes were systematically characterized and analyzed. The best PEC activity with the highest current density of 1.8 mA/cm2 at 1.23 VRHE was achieved when Td was 30 min, and the sample showed the highest degradation efficiency towards tetracycline hydrochloride degradation (TCH) as well. The enhanced PEC performance was ascribed to the excellent charge transport efficiency as well as a lower carrier recombination rate, which benefited from the formation of BiVO4/BDD ultra-micro p-n heterojunction photoelectrodes and the porous structures of BiVO4. These novel photoanodes were expected to be employed in the practical PEC applications of energy regeneration and environmental management in the future.

Colorimetric and fluorescent probes for the rapid detection of profenofos in farmland system.

Colorimetric and fluorescent sensors were developed for the detection of profenofos. The colorimetric assay relied on the aggregation of cysteine modified gold nanoparticles (Au-cys) composite caused by the hydrogen bond and Au-S bond between profenofos and Au-cys. The further addition of S, N-doped carbon quantum dots (CDs) (fluorescence quantum yield up to 98%) into the Au-cys system depended on the change of fluorescence intensity of Au-cys-CDs owing to the inner filter effect between Au-cys and CDs. Under the optimal conditions, the sensor exhibits good linearity within 0.2-1.2 mg L-1 and 20-320 µg L-1, and limit of detection of 21.7 µg L-1 and 5.5 µg L-1 in colorimetry and fluorescence mode, respectively. The developed sensor did not only possess favorable selectivity and sensitivity, but also feasibility of usage in the actual detection of profenofos in farmland system samples.

Cyanamide Passivation Enables Robust Elemental Imaging of Metal Halide Perovskites at Atomic Resolution.

Lead halide perovskites (LHPs) have attracted a tremendous amount of attention because of their applications in solar cells, lighting, and optoelectronics. However, the atomistic principles underlying their decomposition processes remain in large part obscure, likely due to the lack of precise information about their local structures and composition along regions with dimensions on the angstrom scale, such as crystal interfaces. Aberration-corrected scanning transmission electron microscopy combined with X-ray energy dispersive spectroscopy (EDS) is an ideal tool, in principle, for probing such information. However, atomic-resolution EDS has not been achieved for LHPs because of their instability under electron-beam irradiation. We report the fabrication of CsPbBr3 nanoplates with high beam stability through an interface-assisted regrowth strategy using cyanamide. The ultrahigh stability of the nanoplates primarily stems from two contributions: defect-healing self-assembly/regrowth processes and surface modulation by strong electron-withdrawing cyanamide molecules. The ultrahigh stability of as-prepared CsPbBr3 nanoplates enabled atomic-resolution EDS elemental mapping, which revealed atomically and elementally resolved details of the LHP nanostructures at an unprecedented level. While improving the stability of LHPs is critical for device applications, this work illustrates how improving the beam stability of LHPs is essential for addressing fundamental questions on structure-property relations in LHPs.

Antisolvent solvothermal synthesis of MAPbBr3 nanocrystals for efficient solar photodecomposition of methyl orange.

Exploring high performance photocatalysts is of great importance to relieve the environment pollution issues. In this paper, we introduce a facile antisolvent solvothermal method to synthesize methylammonium lead tribromide perovskite (MAPbBr3) nanocrystals and successfully employ them as efficient photocatalysts. Compared to the room temperature synthesized MAPbBr3 (RT-MAPbBr3), the antisolvent solvothermal synthesized MAPbBr3 (AS-MAPbBr3) has multiple outstanding properties, such as improved crystallinity with lower grain boundary density, enhanced light absorption in visible range, suitable band gap of 2.31 eV and extended photoluminescence (PL) lifetime as long as 2627.82 ns. By taking advantages of the above merits, the AS-MAPbBr3 exhibits efficient photocatalytic performance by decomposition of methyl orange under solar light. A high apparent rate constant of 101.2 × 10-3 is achieved along with excellent cyclability, which significantly outperforms the RT-MAPbBr3 (56.0 × 10-3) and P25 (16.5 × 10-3). The underlying mechanism for MO photocatalytic degradation is deeply explored and proposed. Our present study suggests that the antisolvent solvothermal method can be a promising method to synthesize perovskite nanocrystals, and might also provide some insights in developing a series of high performance perovskite based photocatalysts.