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Formamidinium lead iodide (FAPbI3) is the benchmark material for the most efficient near‐infrared perovskite light‐emitting diodes (LEDs) and a promising gain medium for perovskite‐based coherent light sources. Thus, it is crucial to understand and control its defect chemistry to harness the full potential of its exceptional radiative recombination properties. Here, this topic is addressed by tailoring the I− to Br− ratio in the perovskite composition. It is found that introducing small Br− quantities improves the yield of radiative recombination with a beneficial impact on both spontaneous and amplified spontaneous emission (ASE) and improves the semiconductor photostability leading to reduced luminescence efficiency roll‐off and enhanced radiance in LEDs. By employing photoemission electron microscopy (PEEM), this improvement in optoelectronic performance can be directly correlated to a reduced hole‐trapping activity achieved by replacing iodide with bromide, thus, providing a convenient yet powerful synthetic approach to control the defect chemistry of the material and fostering its implementation in advanced photonic platforms. [ABSTRACT FROM AUTHOR]

The role of tin fluoride in defining the complex surface chemistry of tin halide perovskites (THP) is investigated. It is shown that oxygen is found on the surface of tin perovskite thin films even if prepared under a virtually inert environment; however, the presence of SnF2 strongly affects the chemical nature of the found species. Oxygen primarily binds to tin in the form of SnO2 only when SnF2 is added to the precursor solution, while it preferentially binds to carbon and hydrogen in pristine materials. Thanks to the spatial mapping of both the local chemical environment and photoluminescence, it is shown that pristine films have a higher accumulation of iodine at the grain boundaries while the addition of SnF2 allows for preserving the perovskite phase and reducing chemical and optical heterogeneities. Finally, SnF2 does not help in avoiding nor slowing down the degradation of the perovskite film when exposed to ambient air and oxidation occurs on the whole THP‐grain surface. These results provide insightful guidance toward understanding oxidation in THPs and elucidate its detrimental effect on the material's properties. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of the Parotis chlorochroalis was sequenced, revaeling a length of 15239 bp with 37 genes and an A + T-rich region. All c13 PCGs begin with typical ATN codons, except COI gene, which starts with CGA. Eleven genes terminate with TAA, two with T–. All 22 tRNA genes exhibit typical cloverleaf structure except for trnS1 P. chlorochroalis has two relatively conserved intergenic regions and two relatively conserved overlapping regions. Phylogenetic analysis support P. chlorochroalis belongs to subfamily Spilomelinae, the topologies of Crambidae are highly congruent with previous studies. This newly sequences mitochondrial genome provides valuable resources for taxonomic inference and evolutionary studies of genus Parotis. [ABSTRACT FROM AUTHOR]

Metal halide perovskites are promising semiconductors with promising applications in optoelectronic and photonic technologies. When coherent emission applications are targeted, materials with lower lasing thresholds and increased stabilities must be developed to increase the performance under continuous wave optical pumping condition and finally allow the realization of the long sought‐after electrically pumped lasers. Perovskite multiple‐quantum‐wells (MQWs) can potentially ease the population inversion by confining photoexcitation within the heterostructure's wells, but their fabrication process and structural design still require a delicate optimization to make them valuable photonic platforms. Here, perovskite MQWs are fabricated based on organic semiconductors and CsPbBr3, using a facile and easily scalable sequential single‐source vacuum evaporation method. Perovskite with the organic interlayer shows radically enhanced phase stability, passivated defects, and improved radiative recombination properties. In this way, upon proper design of the heterostructure wells and barriers thicknesses, optically pumped amplified spontaneous emission can be achieved. This work reports an effective fabrication approach for perovskite MQWs, while providing a deeper understanding of their photophysical properties to foster their application as coherent light emitters. [ABSTRACT FROM AUTHOR]

The soft and polar nature of quasi‐2D (PEA)2PbBr4 perovskite, and robust photo‐generated excitons lead exciton‐polaritons and exciton‐polarons as the important phenomena near the band edge for application in the lighting aspect. In this work, a convenient methodology is proposed based on the polariton resonant modes in temperature‐dependent (77 K to RT) spectroscopy, and investigate the effect of these quasi‐particles on refractive index dispersion. The large binding energy (≈335 meV) of quasi‐2D excitons is obtained by the reflectance measurements at 77 K. Stable exciton‐polaritons and exciton‐polarons are confirmed by energy dispersions and the observation of self‐trapped exciton‐polaron state, respectively. Furthermore, the large negative thermal‐optic coefficient due to damping effect of exciton‐phonon scattering is observed. The phenomenon is opposite to those observed in conventional semiconductors (e.g., Si, Ge, GaN, AlN, GaAs, AlAs, and ZnO etc.). The observed stable negative thermal‐optic coefficients from 160 K to RT indicate that the quasi‐2D perovskite can be used as a phase compensator for conventional semiconductor materials. [ABSTRACT FROM AUTHOR]