Understanding the growth mechanism of BaZrS3 chalcogenide perovskite thin films from sulfurized oxide precursors

Barium zirconium sulfide BaZrS3 is an earth abundant and environmentally friendly chalcogenide perovskite with promising properties for various energy conversion applications. Recently, sulfurization of oxide precursors has been suggested as a viable solution for effective synthesis, especially from the perspective of circumventing the difficulty of handling alkali earth metals. In this work, we explore in detail the synthesis of BaZrS3 from Ba Zr O oxide precursor films sulfurized at temperatures ranging from 700 amp; 9702;C to 1000 amp; 9702;C. We propose a formation mechanism of BaZrS3 based on a two step reaction involving an intermediate amorphization step of the BaZrO3 crystalline phase. We show how the diffusion of sulfur S species in the film is the rate limiting step of this reaction. The processing temperature plays a key role in determining the total fraction of conversion from oxide to sulfide phase at a constant flow rate of the sulfur containing H2S gas used as a reactant. Finally, we observe the formation of stoichiometric BaZrS3 1 1 3 , even under Zr rich precursor conditions, with the formation of ZrO2 as a secondary phase. This marks BaZrS3 quite unique among the other types of chalcogenides, such as chalcopyrites and kesterites, which can instead accommodate quite a large range of non stoichiometric compositions. This work opens up a pathway for further optimization of the BaZrS3 synthesis process, straightening the route towards future applications of this materia

Green Light Photoelectrocatalysis with Sulfur Doped Carbon Nitride Using Triazole Purpald for Enhanced Benzylamine Oxidation and Oxygen Evolution Reactions

Materials dictate carbon neutral industrial chemical processes. Visible light photoelectrocatalysts from abundant resources will play a key role in exploiting solar irradiation. Anionic doping via pre organization of precursors and further co polymerization creates tuneable semiconductors. Triazole derivative purpald, an unexplored precursor with sulfur S container, combined in different initial ratios with melamine during one solid state polycondensation with two thermal steps yields hybrid S doped carbon nitrides C3N4 . The series of S doped C3N4 based materials show enhanced optical, electronic, structural, textural, and morphological properties and exhibit higher performance in organic benzylamine photooxidation, oxygen evolution, and similar energy storage capacitor brief investigation . 50M 50P exhibits the highest photooxidation conversion 84 3 of benzylamine to imine at 535 nm green light for 48 h, due to a discrete shoulder amp; 8776;700 nm, high sulfur content, preservation of crystal size, new intraband energy states, structural defects by layer distortion, and 10 16 nm pores with arbitrary depth. This work innovates by studying the concomitant relationships between 1 the precursor decomposition while C3N4 is formed, 2 the insertion of S impurities, 3 the S doped C3N4 property activity relationships, and 4 combinatorial surface, bulk, structural, optical, and electronic characterization analysis. This work contributes to the development of disordered long visible light photocatalysts for solar energy conversion and storag

Anti-tumour necrosis factor discontinuation in inflammatory bowel disease patients in remission: study protocol of a prospective, multicentre, randomized clinical trial

Background: Patients with inflammatory bowel disease who achieve remission with anti-tumour necrosis factor (anti-TNF) drugs may have treatment withdrawn due to safety concerns and cost considerations, but there is a lack of prospective, controlled data investigating this strategy. The primary study aim is to compare the rates of clinical remission at 1?year in patients who discontinue anti-TNF treatment versus those who continue treatment. Methods: This is an ongoing, prospective, double-blind, multicentre, randomized, placebo-controlled study in patients with Crohn?s disease or ulcerative colitis who have achieved clinical remission for ?6?months with an anti-TNF treatment and an immunosuppressant. Patients are being randomized 1:1 to discontinue anti-TNF therapy or continue therapy. Randomization stratifies patients by the type of inflammatory bowel disease and drug (infliximab versus adalimumab) at study inclusion. The primary endpoint of the study is sustained clinical remission at 1?year. Other endpoints include endoscopic and radiological activity, patient-reported outcomes (quality of life, work productivity), safety and predictive factors for relapse. The required sample size is 194 patients. In addition to the main analysis (discontinuation versus continuation), subanalyses will include stratification by type of inflammatory bowel disease, phenotype and previous treatment. Biological samples will be obtained to identify factors predictive of relapse after treatment withdrawal. Results: Enrolment began in 2016, and the study is expected to end in 2020. Conclusions: This study will contribute prospective, controlled data on outcomes and predictors of relapse in patients with inflammatory bowel disease after withdrawal of anti-TNF agents following achievement of clinical remission. Clinical trial reference number: EudraCT 2015-001410-1

Deep Defect States in Wide Band Gap ABX 3 Halide Perovskites

We find 4 different deep defect states in polycrystalline layers of mixed cation lead tribromide from high sensitivity modulated surface photovoltage SPV spectroscopy. Measurements were performed with different contact configurations, on complete solar cells and on samples before and after aging or stressing at 85 C under illumination. Three of the four states, with energies of 0.63, 0.73 and 1.35 eV below the conduction band edge, are assigned to intrinsic defects whereas defect states in the middle of the band gap are thought to be associated with uncontrolled impuritie