Epitaxial Growth of CsPbBr₃ Pyramids/CdS Nanobelt Heterostructures for High-Performance Photodetectors

Perovskites have great potential for optoelectronic applications due to their high photoluminescence quantum yield, large absorption coefficient, great defect tolerance, and adjustable band gap. Perovskite heterostructures may further enhance the performance of optoelectronic devices. So far, however, most of perovskite heterostructures are fabricated by mechanical stacking or spin coating, which could introduce a large number of defects or impurities at the heterointerface owing to the random stacking process. Herein, we report the epitaxial growth of CsPbBr3 pyramids/CdS nanobelt heterostructures via a 2-step vapor deposition route. The CsPbBr3 triangular pyramids are well aligned on the surface of CdS nanobelts with the epitaxial relationships of (0–22)CsPbBr3||(1–20)CdS and (−211)CsPbBr3||(002)CdS. Time-resolved photoluminescence results reveal that effective charge transfer occurred at the heterointerface, which can be attributed to the type-II band arrangement. Theoretical simulations reveal that the unique CsPbBr3 pyramids/CdS nanobelt structure facilitates diminishing the reflection losses and enhancing the light absorption. The photodetector based on these CsPbBr3 pyramids/CdS nanobelt heterostructures exhibited an ultrahigh photoswitching ratio of 2.14 × 105, a high responsivity up to 4.07 × 104 A/W, a high detectivity reaching 1.36 × 1013 Jones, fast photoresponses (τrise = 472 μs and τdecay = 894 μs), low dark current, and suppressed hysteresis

Thiomolybdate [Mo₃S₁₃]^2– Nanoclusters Anchored on Reduced Graphene Oxide-Carbon Nanotube Aerogels for Efficient Electrocatalytic Hydrogen Evolution

Thiomolybdate [Mo₃S₁₃]^2– nanoclusters anchored on reduced graphene oxide-carbon nanotube (rGO-CNTs) aerogels were used as a new catalyst for efficient electrocatalytic hydrogen evolution. The elemental distribution of sulfur (S) corresponded well to the Mo distribution, and both Mo and S elements distributed evenly in the Mo₃S₁₃@rGO-CNTs aerogels. Results indicated that [Mo₃S₁₃]^2– nanoclusters inherently exposed a high number of active edge sites, which greatly improved the electrocatalytic hydrogen evolution. The new peak at 168.8 eV corresponded to the characteristic S–O binding in the S 2p region of Mo₃S₁₃@rGO-CNTs, indicating that the [Mo₃S₁₃]^2– clusters were bond onto the rGO-CNTs aerogels through S–O binding. The strong support of rGO-CNTs aerogels suppressed the aggregation of [Mo₃S₁₃]^2– nanoclusters, exposing more active surface and electrons diffusions on the surface of Mo₃S₁₃@rGO-CNTs aerogels. Mo₃S₁₃@rGO-CNTs aerogels laden with 20 mg of [Mo₃S₁₃]^2– exhibited close hydrogen evolution reaction (HER) performance as compared with that of [Mo₃S₁₃-120]@rGO-CNTs aerogels laden with 120 mg of [Mo₃S₁₃]^2– nanoclusters. This indicated the extremely high HER performance of [Mo₃S₁₃]^2– even at low mass. As a result, Mo₃S₁₃@rGO-CNTs aerogels enabled remarkable electrochemical performances showing a low overpotential (0.179 V at 10 mA cm^–2) with a small Tafel slope, reduced transfer resistance, and excellent stability

The holotype of <i>Microraptor gui</i>, IVPP V 13352 under UV light.

<p>Different filters were employed for parts A and B, hence the difference in colour and appearance. A also is labeled to indicate the preserved feathers (grey arrows) and the ‘halo’ around the specimen where they appear to be absent (black arrows) as well as phosphatised tissues (white arrows). Scale bars are 5 cm in both A and B.</p

Close up of the lower part of the holotype under UV light.

<p>Variation in the phosphatised tissues can be seen (white arrows) as well as the bright reflectance of various glues and preservatives that have been applied to the specimen at various times (black arrows). Scale bar of 2 cm.</p

Comparison of the quadrates in <i>Hualianceratops wucaiwanensis</i> and <i>Yinlong downsi</i>.

<p>(A-F) right quadrate and quadratojugal of <i>Hualianceratops wucaiwanensis</i>. (A) photograph in lateral view, (B) photograph in caudal view, (C) photograph in rostral view, (D) drawing in lateral view, (E) drawing in caudal view, (F) drawing in rostral view. (G-I) left quadrate of <i>Yinlong</i> (IVPP V18637) flipped for comparison with the right side. (G) Photograph in lateral view, (H) photograph in caudal view, (I) photograph in rostral view. Abbreviations: gr, groove; q, quadrate; qj, quadratojugal; qj.a, articulation with the quadratojugal; qn, quadrate notch.</p

The mandible of <i>Hualianceratops wucaiwanensis</i> (IVPP V18641).

<p>(A) photograph in lateral view, (B) drawing in lateral view, (C) photograph in ventral view, (D) drawing in ventral view. Abbreviations: an, angular; d, dentary; emf, external mandibular fenestra; imf, inner mandibular fenestra; lsp, left splenial; pra, prearticular; pd, predentary; rsp, right splenial; sa, surangular.</p

Comparison of the mandible in basal ceratopsians in right lateral view.

<p>(A) <i>Hualianceratops wucaiwanensis</i> (IVPP V18641), (B) <i>Hongshanosaurus houi</i> (IVPP V12617), (C) <i>Yinlong downsi</i> (IVPP V14530), (D) <i>Archaeoceratops oshimai</i> (IVPP V11114), (E) <i>Chaoyangsaurus youngi</i> (IGCAGS V371), (F) <i>Liaoceratops yanzigouensis</i> (IVPP V12633). Abbreviations: an, angular; co, coronoid; d, dentary; pd, predentary; sa, surangular.</p

The articulated left partial jugal and quadratojugal of <i>Hualianceratops wucaiwanensis</i> (IVPP V18641).

<p>(A) photograph in lateral view, (B) photograph in medial view, (C) drawing in lateral view; (D) drawing in medial view. Abbreviations: cp, caudomedial process of the jugal; dp, caudodorsal process of the jugal; qj, quadratojugal; q, quadrate; j, jugal.</p

A New Taxon of Basal Ceratopsian from China and the Early Evolution of Ceratopsia

<div><p>Ceratopsia is one of the best studied herbivorous ornithischian clades, but the early evolution of Ceratopsia, including the placement of <i>Psittacosaurus</i>, is still controversial and unclear. Here, we report a second basal ceratopsian, <i>Hualianceratops wucaiwanensis</i> gen. et sp. nov., from the Upper Jurassic (Oxfordian) Shishugou Formation of the Junggar Basin, northwestern China. This new taxon is characterized by a prominent caudodorsal process on the subtemporal ramus of the jugal, a robust quadrate with an expansive quadratojugal facet, a prominent notch near the ventral region of the quadrate, a deep and short dentary, and strongly rugose texturing on the lateral surface of the dentary. <i>Hualianceratops</i> shares several derived characters with both <i>Psittacosaurus</i> and the basal ceratopsians <i>Yinlong</i>, <i>Chaoyangsaurus</i>, and <i>Xuanhuaceratops</i>. A new comprehensive phylogeny of ceratopsians weakly supports both <i>Yinlong</i> and <i>Hualianceratops</i> as chaoyangsaurids (along with <i>Chaoyangsaurus</i> and <i>Xuanhuaceratops</i>), as well as the monophyly of Chaoyangosauridae + <i>Psittacosaurus</i>. This analysis also weakly supports the novel hypothesis that Chaoyangsauridae + <i>Psittacosaurus</i> is the sister group to the rest of Neoceratopsia, suggesting a basal split between these clades before the Late Jurassic. This phylogeny and the earliest Late Jurassic age of <i>Yinlong</i> and <i>Hualianceratops</i> imply that at least five ceratopsian lineages (<i>Yinlong</i>, <i>Hualianceratops</i>, <i>Chaoyangsaurus</i> + <i>Xuanhuaceratops</i>, <i>Psittacosaurus</i>, Neoceratopsia) were present at the beginning of the Late Jurassic.</p></div

Close up of the chest of the holotype, close to the sternal plates under UV light.

<p>As with <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009223#pone-0009223-g003" target="_blank">figure 3</a>, this shows that the feathers do indeed penetrate the halo (grey arrows) when seen in UV and approach or reach the bones. These are not seen in natural light due to the overlying phosphatised tissues, but the striations of the feathers are clearly visible despite this covering. Scale bar of 1 cm.</p