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1. Stabilizing 2D Pt‐Based Halide Perovskites via Solvent Lone Pair Donation

   https://doi.org/10.1002/adom.202402435  

   Liu, Huilong; Biswas, Maitreyo; Smith, Walter J; Barnard, Edward; Beechem, Thomas; Mannodi‐Kanakkithodi, Arun; Bansal, Shubhra (October 2024, Advanced Optical Materials)

   Abstract Platinum‐based halide perovskites exhibit promising optoelectronic properties along with merits of low‐temperature processing and stability. Current research on Pt halide perovskites is limited to 0D A₂BX₆structure as the ABX₃3D structure is thermodynamically unstable. Herein, the study reports the stabilization of the ABX₃structure into a 2D layered phase, CsPtI₃(DMSO), that is stable up to 181.5 °C. The 2D phase shows an excitonic peak at the absorption edge of 600 nm, indicating quantum confinement. It also exhibits a large Stokes shift due to intersystem crossing (ISC), with a quenched singlet excitonic fluorescence at 610 nm and strong triplet emission at 852 nm. Pt(II) co‐ordinates with dimethyl sulfoxide (DMSO) via σ‐donation of S lone‐pair electrons and π‐ back donation from Pt to S, stabilizing CsPtI₃(DMSO) layered structure. The strong electronic interaction between DMSO and Pt(II) and orbital mixing lead to spin‐orbit‐coupling, facilitating ISC and singlet‐to‐triplet exciton energy transfer. The interaction of Pt and DMSO is further confirmed by addition of thioacetamide (TAA), a strong S‐donor, which retards the formation of 2D layered structure, and directly results in Cs₂PtI₆and Pt. 

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2. In situ formation of pseudohalide anions induced by humid air and light passivates formamidinium‐based halide perovskites

   https://doi.org/10.1002/inf2.12643  

   Ye, Jiselle Y; Kerner, Ross A; Jiang, Qi; Yang, Fengjiu; Yang, Jonghee; Ahmadi, Mahshid; Harvey, Steven P; Steirer, Kenneth X; Kuciauskas, Darius; Berry, Joseph J; et al (February 2025, InfoMat)

   Abstract Metal halide perovskites based on formamidinium (FA), or FA‐rich compositions have shown great promise for high‐performance photovoltaics. A deeper understanding of the impact of ambient conditions (e.g., moisture, oxygen, and illumination) on the possible reactions of FA‐based perovskite films and their processing sensitivities has become critical for further advances toward commercialization. Herein, we investigate reactions that take place on the surface of the FA_0.7Cs_0.3, mixed Br/I wide bandgap perovskite thin films in the presence of humid air and ambient illumination. The treatment forms a surface layer containing O, OH, and N‐based anions. We propose the latter originates from formamidine trapped at the perovskite/oxide interface reacting further to cyanide and/or formamidinate—an understudied class of pseudohalides that bind to Pb. Optimized treatment conditions improve photoluminescence quantum yield owing to both reduced surface recombination velocity and increased bulk carrier lifetime. The corresponding perovskite solar cells also exhibit improved performance. Identifying these reactions opens possibilities for better utilizing cyanide and amidinate ligands, species that may be expected during vapor processing of FA‐based perovskites. Our work also provides new insights into the self‐healing or self‐passivating of MA‐free perovskite compositions where FA and iodide damage could be partially offset by advantageous reaction byproducts. image 

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3. Full band Monte Carlo simulation of AlInAsSb digital alloys

   https://doi.org/10.1002/inf2.12112  

   Zheng, Jiyuan; Ahmed, Sheikh Z.; Yuan, Yuan; Jones, Andrew; Tan, Yaohua; Rockwell, Ann K.; March, Stephen D.; Bank, Seth R.; Ghosh, Avik W.; Campbell, Joe C. (November 2020, InfoMat)

   Abstract Avalanche photodiodes fabricated from AlInAsSb grown as a digital alloy exhibit low excess noise. In this article, we investigate the band structure‐related mechanisms that influence impact ionization. Band‐structures calculated using an empirical tight‐binding method and Monte Carlo simulations reveal that the mini‐gaps in the conduction band do not inhibit electron impact ionization. Good agreement between the full band Monte Carlo simulations and measured noise characteristics is demonstrated. image 

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4. High‐throughput combinatorial approach expedites the synthesis of a lead‐free relaxor ferroelectric system

   https://doi.org/10.1002/inf2.12561  

   Zhang, Di; Harmon, Katherine J; Zachman, Michael J; Lu, Ping; Kim, Doyun; Zhang, Zhan; Cucciniello, Nicholas; Markland, Reid; Ssennyimba, Ken William; Zhou, Hua; et al (June 2024, InfoMat)

   Abstract Developing novel lead‐free ferroelectric materials is crucial for next‐generation microelectronic technologies that are energy efficient and environment friendly. However, materials discovery and property optimization are typically time‐consuming due to the limited throughput of traditional synthesis methods. In this work, we use a high‐throughput combinatorial synthesis approach to fabricate lead‐free ferroelectric superlattices and solid solutions of (Ba_0.7Ca_0.3)TiO₃(BCT) and Ba(Zr_0.2Ti_0.8)O₃(BZT) phases with continuous variation of composition and layer thickness. High‐resolution x‐ray diffraction (XRD) and analytical scanning transmission electron microscopy (STEM) demonstrate high film quality and well‐controlled compositional gradients. Ferroelectric and dielectric property measurements identify the “optimal property point” achieved at the composition of 48BZT–52BCT. Displacement vector maps reveal that ferroelectric domain sizes are tunable by varying {BCT–BZT}_Nsuperlattice geometry. This high‐throughput synthesis approach can be applied to many other material systems to expedite new materials discovery and properties optimization, allowing for the exploration of a large area of phase space within a single growth. image 

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5. To what extent do physiological tolerances determine elevational range limits of mammals?

   https://doi.org/10.1113/JP284586  

   Storz, Jay F; Scott, Graham R (October 2023, The Journal of Physiology)

   Abstract A key question in biology concerns the extent to which distributional range limits of species are determined by intrinsic limits of physiological tolerance. Here, we use common‐garden data for wild rodents to assess whether species with higher elevational range limits typically have higher thermogenic capacities in comparison to closely related lowland species. Among South American leaf‐eared mice (genusPhyllotis), mean thermogenic performance is higher in species with higher elevational range limits, but there is little among‐species variation in the magnitude of plasticity in this trait. In the North American rodent genusPeromyscus, highland deer mice (Peromyscus maniculatus) have greater thermogenic maximal oxygen uptake () than lowland white‐footed mice (Peromyscus leucopus) at a level of hypoxia that matches the upper elevational range limit of the former species. In highland deer mice, the enhanced thermogenic in hypoxia is attributable to a combination of evolved and plastic changes in physiological pathways that govern the transport and utilization of O₂and metabolic substrates. Experiments withPeromyscusmice also demonstrate that exposure to hypoxia during different stages of development elicits plastic changes in cardiorespiratory traits that improve thermogenic via distinct physiological mechanisms. Evolved differences in thermogenic capacity provide clues about why some species are able to persist in higher‐elevation habitats that lie slightly beyond the tolerable limits of other species. Such differences in environmental tolerance also suggest why some species might be more vulnerable to climate change than others.image 

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