Two-dimensional (2D) materials have been well developed for polarization-sensitive photodetection, while new 2D members used in shortwave region (>2.5 eV) still remain scarce. The family of 2D hybrid perovskite ferroelectrics, in which the coupling of spontaneous polarization (P s ) and light benefits dissociation of photoinduced carriers, has shown great potential in this portfolio. Here, we report a new 2D hybrid perovskite ferroelectric, [CH 3 (CH 2 ) 3 NH 3 ] 2 (CH 3 NH 3 )Pb 2 Br 7 (1), which exhibits a superior P s of 3.6 μC/cm 2 and a relatively wide bandgap (∼2.55 eV). The unique 2D perovskite motif results in an intrinsic anisotropy of optical absorption (the ratio α c /α a ≈ 1.9 at 405 nm), involving its polarizationsensitive activity. As expected, the strongest photoresponses were observed along the c-axis (i.e., parallel to P s ), along with a large dichroism ratio (I ph c /I ph a ≈ 2.0) and highly sensitive detectivity up to ∼10 9 Jones. Further, crystal-device of 1 shows a fast responding rate (∼20 μs) and excellent antifatigued merits. As pioneering work, 1 is the first polarization-sensitive ferroelectric in the new branch of 2D hybrid perovskites. Such intriguing behaviors make 1 a potential candidate for the shortwave polarized-light detection, which also sheds light on new functionalities for future optoelectronic application of hybrid perovskites.

The non-π-conjugated sulfate system has long been overlooked as potential deep-UV nonlinear optical (NLO) materials. Here we report two asymmetric anhydrous sulfates, namely, NH 4 NaLi 2 (SO 4 ) 2 (Ι) and (NH 4 ) 2 Na 3 Li 9 (SO 4 ) 7 (Π), which consist of non-πconjugated [SO 4 ] 2− anions. Their single crystals can be readily grown by a facile evaporation method from water solution. Both sulfates are transparent down to the deep-UV region. Interestingly, there is a large NLO gap between I and Π, with phase-matching NLO responses of 1.1 and 0.5 times that of the benchmark KH 2 PO 4 , respectively. The first-principles studies reveal that the non-π-conjugated [SO 4 ] 2− anions are the dominate NLOactive groups, and the large NLO gap between I and Π can be ascribed to the nonbonding O 2p orbitals of different orientations in the crystallographically independent S1O 4 groups. This work provides an innovative non-πconjugated source that is distinct from the traditional πconjugated ones for deep-UV NLO materials.

: The Japan Trench land slope at a depth of 6,400 m is the deepest cold-seep environment with Calyptogena communities. Sediment samples from inside and beside the Calyptogena communities were collected, and the microbial diversity in the sediment samples was studied by molecular phylogenetic techniques. From DNA extracted directly from the sediment samples, 16S rDNAs were amplified by the polymerase chain reaction method. The sequences of the amplified 16S rDNAs selected by restriction fragment length polymorphism analysis were determined and compared with sequences in DNA databases. The results showed that 33 different bacterial 16S rDNA sequences from the two samples analyzed fell into similar phylogenetic categories, the alpha-, gamma-, delta-, and varepsilon-subdivisions of Proteobacteria, Cytophaga, and gram-positive bacteria; some of the 16S rDNA sequences were common to both samples. delta- and varepsilon-Proteobacteria-related sequences were abundant in both sediments. These sequences are mostly related to sulfate-reducing or sulfur-reducing bacteria and epibionts, respectively. Eight different archaeal 16S rDNA sequences were cloned from the sediments. The majority of the archaeal 16S rDNA sequences clustered in Crenarchaeota and showed high similarities to marine group I archaeal rDNA. A Methanococcoides burtonii-related sequence obtained from the sediment clustered in the Euryarchaeota indicating that M. burtonii-related strains in the area of Calyptogena communities may contribute to production of methane in this environment. From these results, we propose a possible model of sulfur circulation within the microbial community and that of Calyptogena clams in the cold-seep environment.