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1. Solvothermal Synthesis of [Cr ₇ S ₈ (en) ₈ Cl ₂ ]Cl ₃  ⋅ 2H ₂ O with Magnetically Frustrated [Cr ₇ S ₈ ] ⁵⁺ Double‐Cubes**

   https://doi.org/10.1002/chem.202103761  

   Gamage, Eranga_H; Clark, Judith_K; Yazback, Maher; Cheng, Hai‐Ping; Shatruk, Michael; Kovnir, Kirill (December 2021, Chemistry – A European Journal)

   Abstract A novel transition metal chalcohalide [Cr₇S₈(en)₈Cl₂]Cl₃ ⋅ 2H₂O, with [Cr₇S₈]⁵⁺dicubane cationic clusters, has been synthesized by a low temperature solvothermal method, using dimethyl sulfoxide (DMSO) and ethylenediamine (en) solvents. Ethylenediamine ligand exhibits bi‐ and monodentate coordination modes; in the latter case ethylenediamine coordinates to Cr atoms of adjacent clusters, giving rise to a 2D polymeric structure. Although magnetic susceptibility shows no magnetic ordering down to 1.8 K, a highly negative Weiss constant,θ=−224(2) K, obtained from Curie‐Weiss fit of inverse susceptibility, suggests strong antiferromagnetic (AFM) interactions betweenS=3/2 Cr(III) centers. Due to the complexity of the system with (2S+1)⁷=16384 microstates from seven Cr³⁺centers, a simplified model with only two exchange constants was used for simulations. Density‐functional theory (DFT) calculations yielded the two exchange constants to beJ₁=−21.4 cm⁻¹andJ₂=−30.2 cm⁻¹, confirming competing AFM coupling between the shared Cr³⁺center and the peripheral Cr³⁺ions of the dicubane cluster. The best simulation of the experimental data was obtained withJ₁=−20.0 cm⁻¹andJ₂=−21.0 cm⁻¹, in agreement with the slightly stronger AFM exchange within the triangles of the peripheral Cr³⁺ions as compared to the AFM exchange between the central and peripheral Cr³⁺ions. This compound is proposed as a synthon towards magnetically frustrated systems assembled by linking dicubane transition metal‐chalcogenide clusters into polymeric networks. 

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2. Rapid Growth of Monolayer MoSe ₂ Films for Large‐Area Electronics

   https://doi.org/10.1002/aelm.202001219  

   Zhang, Danzhen; Wen, Chengyu; Mcclimon, John_Brandon; Masih_Das, Paul; Zhang, Qicheng; Leone, Grace_A; Mandyam, Srinivas_V; Drndić, Marija; Johnson, Jr., Alan_T_Charlie; Zhao, Meng‐Qiang (May 2021, Advanced Electronic Materials)

   Abstract The large‐scale growth of semiconducting thin films on insulating substrates enables batch fabrication of atomically thin electronic and optoelectronic devices and circuits without film transfer. Here an efficient method to achieve rapid growth of large‐area monolayer MoSe₂films based on spin coating of Mo precursor and assisted by NaCl is reported. Uniform monolayer MoSe₂films up to a few inches in size are obtained within a short growth time of 5 min. The as‐grown monolayer MoSe₂films are of high quality with large grain size (up to 120 µm). Arrays of field‐effect transistors are fabricated from the MoSe₂films through a photolithographic process; the devices exhibit high carrier mobility of ≈27.6 cm²V^–1s^–1and on/off ratios of ≈10⁵. The findings provide insight into the batch production of uniform thin transition metal dichalcogenide films and promote their large‐scale applications. 

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3. A highly stable and conductive cerium‐doped Li ₇ P ₃ S ₁₁ glass‐ceramic electrolyte for solid‐state lithium–sulfur batteries

   https://doi.org/10.1111/jace.19712  

   Mirtaleb, Amirhossein; Wang, Ruigang (June 2024, Journal of the American Ceramic Society)

   Abstract In this report, a facile wet chemical method using acetonitrile combined with thermal annealing was used to prepare Li₂S‐P₂S₅(LPS) based glass‐ceramic electrolytes with (1 wt%, 3 wt%, and 5 wt% Ce₂S₃) and without Ce₂S₃doping. The crystal structure, ionic conductivity, and chemical stability of Li₇P₃S₁₁glass‐ceramic electrolytes were examined at varying temperatures (250–350°C). The results indicated that the highest ionic conductivity of 3.15 × 10⁻⁴S cm⁻¹for pure Li₇P₃S₁₁was observed at a temperature of 325°C. By incorporating 1 wt% Ce₂S₃and subjecting it to a heat treatment at 250°C, the glass ceramic electrolyte attained a remarkable ionic conductivity of 7.7 × 10⁻⁴(S cm⁻¹) at 25°C. Furthermore, it exhibited a stable and extensive electrochemical potential range, reaching up to 5 volts when compared to the Li/Li⁺reference electrode. By tuning the glass transition and crystallization temperature, cerium doping seems to make Li₇P₃S₁₁more chemically stable, compared to its original 70Li₂S‐30P₂S₅counterpart. According to Raman and X‐ray photoelectron spectroscopy analyses, cerium doping inhibits the decomposition of highly conductive P₂S₇^4‐(pyro‐thiophosphate) to PS₄³⁻and P₂S₆⁴⁻. Doped LPS has a greater crystallinity and more uniform microstructure than pure LPS, according to XRD, Raman spectroscopy, and scanning electron microscopy analysis. Consequently, Li₇P_2.9Ce_0.1S₁₁electrolyte shows great potential as a solid‐state electrolyte for constructing high‐performance sulfide‐based all‐solid‐state batteries. 

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4. Optical Properties and Photocarrier Dynamics of Bi ₂ O ₂ Se Monolayer and Nanoplates

   https://doi.org/10.1002/adom.201901567  

   Liu, Shuangyan; Tan, Congwei; He, Dawei; Wang, Yongsheng; Peng, Hailin; Zhao, Hui (January 2020, Advanced Optical Materials)

   Abstract A comprehensive experimental study on optical properties and photocarrier dynamics in Bi₂O₂Se monolayers and nanoplates is presented. Large and uniform Bi₂O₂Se nanoplates with various thicknesses down to the monolayer limit are fabricated. In nanoplates, a direct optical transition near 720 nm is identified by optical transmission, photoluminescence, and transient absorption spectroscopic measurements and is attributed to the transition between the valence and conduction bands in the Γ valley. Time‐resolved differential reflection measurements reveal ultrafast carrier thermalization and energy relaxation processes and a photocarrier recombination lifetime of about 200 ps in nanoplates. Furthermore, by spatially resolving the differential reflection signal, a photocarrier diffusion coefficient of about 4.8 cm²s⁻¹is obtained, corresponding to a mobility of about 180 cm²V⁻¹s⁻¹. A similar direct transition is also observed in monolayer Bi₂O₂Se, suggesting that the states in the Γ valley do not change significantly with the thickness. The temporal dynamics of the excitons in the monolayer is quite different from the nanoplates, with a strong saturation effect and fast exciton–exciton annihilation at high densities. Spatially and temporally resolved measurements yield an exciton diffusion coefficient of about 20 cm²s⁻¹. 

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5. Fe‐Ion Bolted VOPO ₄ ∙2H ₂ O as an Aqueous Fe‐Ion Battery Electrode

   https://doi.org/10.1002/adma.202105234  

   Xu, Yunkai; Wu, Xianyong; Sandstrom, Sean_K; Hong, Jessica_J; Jiang, Heng; Chen, Xin; Ji, Xiulei (October 2021, Advanced Materials)

   Abstract Iron ion batteries using Fe²⁺as a charge carrier have yet to be widely explored, and they lack high‐performing Fe²⁺hosting cathode materials to couple with the iron metal anode. Here, it is demonstrated that VOPO₄∙2H₂O can reversibly host Fe²⁺with a high specific capacity of 100 mAh g⁻¹and stable cycling performance, where 68% of the initial capacity is retained over 800 cycles. In sharp contrast, VOPO₄∙2H₂O's capacity of hosting Zn²⁺fades precipitously over tens of cycles. VOPO₄∙2H₂O stores Fe²⁺with a unique mechanism, where upon contacting the electrolyte by the VOPO₄∙2H₂O electrode, Fe²⁺ions from the electrolyte get oxidized to Fe³⁺ions that are inserted and trapped in the VOPO₄∙2H₂O structure in an electroless redox reaction. The trapped Fe³⁺ions, thus, bolt the layered structure of VOPO₄∙2H₂O, which prevents it from dissolution into the electrolyte during (de)insertion of Fe²⁺. The findings offer a new strategy to use a redox‐active ion charge carrier to stabilize the layered electrode materials. 

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