Alloy negative electrodes for Li-ion batteries.

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH2)4NH3)2PbI4/CH3NH3PbI3 perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm2 solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells. Up-scaling represents a key challenge for photovoltaics based on metal halide perovskites. Using a composite of 2D and 3D perovskites in combination with a printable carbon black/graphite counter electrode; Granciniet al., report 11.2% efficient modules stable over 10,000 hours.

/pdf/one-year-stable-perovskite-solar-cells-by-2d-3d-interface-3uapzy45tv.pdf

One-Year stable perovskite solar cells by 2D/3D interface engineering

Research to develop alternative electrode materials with high energy densities in Li-ion batteries has been actively pursued to satisfy the power demands for electronic devices and hybrid electric vehicles. This critical review focuses on anode materials composed of Group IV and V elements with their composites including Ag and Mg metals as well as transition metal oxides which have been intensively investigated. This critical review is devoted mainly to their electrochemical performances and reaction mechanisms (313 references).

Li-alloy based anode materials for Li secondary batteries.

Polyoxometalates (POMs) are discrete anionic metaloxygen clusters which can be regarded as soluble oxide fragments. They exhibit a great diversity of sizes, nuclearities, and shapes. They are built from the connection of {MOx} polyhedra, M being a d-block element in high oxidation state, usually VIV,V, MoVI, or WVI.1 While these species have been known for almost two centuries, they still attract much interest partly based on their large domains of applications. They play a great role in various areas ranging from catalysis,2 medicine,3 electrochemistry,4 photochromism,5 to magnetism.6 This palette of applications is intrinsically due to the combination of their added value properties (redox properties, large sizes, high negative charges, nucleophilicity...). Parallel to this domain, the organic-inorganic hybrids area has followed a similar expansion during the last 10 years. The concept of organic-inorganic hybrid materials * To whom correspondence should be addressed. E-mail: dolbecq@ chimie.uvsq.fr. Chem. Rev. 2010, 110, 6009–6048 6009

Hybrid Organic−Inorganic Polyoxometalate Compounds: From Structural Diversity to Applications

The hybrid two-dimensional (2D) halide perovskites have recently drawn significant interest because they can serve as excellent photoabsorbers in perovskite solar cells. Here we present the large scale synthesis, crystal structure, and optical characterization of the 2D (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 (n = 1, 2, 3, 4, ∞) perovskites, a family of layered compounds with tunable semiconductor characteristics. These materials consist of well-defined inorganic perovskite layers intercalated with bulky butylammonium cations that act as spacers between these fragments, adopting the crystal structure of the Ruddlesden–Popper type. We find that the perovskite thickness (n) can be synthetically controlled by adjusting the ratio between the spacer cation and the small organic cation, thus allowing the isolation of compounds in pure form and large scale. The orthorhombic crystal structures of (CH3(CH2)3NH3)2(CH3NH3)Pb2I7 (n = 2, Cc2m; a = 8.9470(4), b = 39.347(2) A, c = 8.8589(6)), (CH3(CH2)3NH3)2(CH3NH3)2Pb3I10 (...

http://pubs.acs.org/doi/pdf/10.1021/acs.chemmater.6b00847

Ruddlesden-Popper Hybrid Lead Iodide Perovskite 2D Homologous Semiconductors

First-principles studies of the geometric structures, electronic structures and second-order nonlinear optical properties of polar alkali metal–Mo(VI)–iodate compounds (AMoO3(IO3) (A = Li, Rb and Cs)) have been performed within density functional theory and the independent particle approximation. Our results indicate that, for these compounds, due to the similarity in their anionic groups, the electronic structures and the prominent features of the frequency dependent second-order nonlinear optical susceptibilities are similar, especially for the isostructural Rb and Cs compounds. Also, the calculated SHG coefficients of these compounds are large, which confirms the high response in experimental SHG measurements. By comparing the absolute magnitude of the SHG coefficients, the order LiMoO3(IO3) > RbMoO3(IO3) > CsMoO3(IO3) is clearly established in the low photon energy range. Further analyses based on the spectral and spatial decomposition of the SHG coefficients reveal that the main sources of the SHG properties of these compounds are from the distorted MoO6 and IO3 − groups, and can be mainly attributed to the electronic transition from the nonbonding O 2p states (i.e. the lone-pair electrons of O atoms) to the Mo 4d and some I 5p states. It is noticeable that in these compounds, due to the difference in ion size and coordinate environment, the contributions of alkali metals to the SHG processes are very different: for large cations, such as Rb and Cs, they can be neglected, while for the very small Li, they should be included.

https://iopscience.iop.org/article/10.1088/0953-8984/22/15/155801/pdf

First-principles study of electronic structures and nonlinear optical properties of AMoO3(IO3) (A = Li, Rb and Cs) crystals

Four heteronuclear CuII−HgII halides containing 2,2-bipyridine (bipy) ligands have been synthesized and structurally characterised by single-crystal X-ray diffraction studies. The dinuclear complex [Cu(bipy)2HgCl2Br2] (1) contains a five-coordinate copper(II) ion and a four-coordinate HgII ion, in which the two different types of metal ions are bridged by a pair of chloride anions. [Cu2(bipy)4HgBr4][Hg2Br6] (2) contains a trinuclear [Cu2(bipy)4HgBr4]2+ cation in which the two copper(II) ions are bridged by an [HgBr4]2− tetrahedron via two Cu−Br bonds, and an edge-sharing tetrahedral [Hg2Br6]2− anion. The structure of [Cu2(bipy)4Hg2Br6][Hg4Br10] (3) features a 1-D chain along the diagonal of the a and c axes constructed from tetranuclear [Cu2(bipy)4Hg2Br6]2+ cations interconnected by [Hg4Br10]2− tetramers via elongated Hg−Br contacts (3.185 A). Within the tetranuclear cationic unit, two [Cu(bipy)2]2+ units are bridged by an edge-sharing dimeric tetrahedral [Hg2Br6]2− anion. In the trinuclear complex [Cu(bipy)2Hg2Cl6] (4), each [Hg2Cl6]2− dimer bridges with a [Cu(bipy)2]2+ ion to form a trinuclear [Cu(bipy)2Hg2Cl6] unit, and each pair of such units is bridged by a pair of elongated Hg−Cl bonds [3.043(5) A] to form a dimeric unit. The magnetic properties of 1, 2, and 4 have also been investigated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Syntheses, Crystal Structures and Magnetic Properties of Four CuII-HgII Mixed-Metal Halide Oligomers

The first examples of lanthanide(III) organoarsonates, Ln(L1)(H2O)3 (Ln = La (1), H3L1 = 4-hydroxy-3-nitrophenylarsonic acid), Ln(L1)(H2O)2 (Ln = Nd (2), Gd (3)), and mixed-ligand lanthanide(III) organoarsonates, Ln2(HL1)2(C2O4)(H2O)2 (Ln = Nd (4), Sm (5), Eu (6)), were hydrothermally synthesized and structurally characterized. Compounds 1–3 feature a corrugated lanthanide arsonate layer, in which 1D lanthanide arsonate inorganic chains are further interconnected via bridging L13− ligands. Compounds 4–6 exhibit a complicated 3D network. The interconnection of the lanthanide(III) ions by the bridging arsonate ligand leads to the formation of a novel 3D framework with long narrow 1D tunnels along the a-axis, with the oxalate anions are located at the above tunnels and bridging with lanthanide(III) ions. Compounds 2 and 4 exhibit the characteristic emission bands of the Nd(III) ion, whereas compound 6 displays the characteristic emission bands of the Eu(III) ion. The magnetic properties of compounds 3–6 were also investigated.

/pdf/syntheses-crystal-structures-and-luminescent-properties-of-265d3bv3t1.pdf

Syntheses, crystal structures and luminescent properties of new lanthanide(III) organoarsonates

Two new halogenated selenites, namely, Pb2Cd(SeO3)2X2 (X = Cl and Br), were synthesized via mild hydrothermal reactions. The isomorphic compounds crystallized in a noncentrosymmetric (NCS) and chiral space group. Their three-dimensional (3D) structures were formed by alternating undulated [Pb2(SeO3)X]∞+ cationic layers and flattened [Cd(SeO3)X]∞− anionic layers. Thermal analyses revealed that the compounds can remain stable up to 500 °C. The SHG efficiencies of Pb2Cd(SeO3)2X2 (X = Cl and Br) are much higher than those of commercial KDP (KH2PO4), and they are phase-matchable. UV-vis-NIR diffuse reflectance spectra revealed that the two compounds exhibited wide optical band gaps. The laser damage thresholds of Pb2Cd(SeO3)2X2 (X = Cl and Br) were measured to be about 38.5 and 35.7 times higher than that of AGS (AgGaS2). Their calculated birefringences were large enough to accomplish phase matching in SHG progression. The SHG density analyses disclosed that the lone pair electrons of the SeO3 and PbOnXm units made major contributions to their nonlinear efficiencies.

Pb2Cd(SeO3)2X2 (X = Cl and Br): two halogenated selenites with phase matchable second harmonic generation

A novel europium(III) coordination polymer with a new double betaine derivative. {[Eu(L1)(NO3)(H2O)3](NO3)2 3.5H2O}n (L= l,3-bis(pyridinio-4-carboxylato)-propane) has been synthesized and its structure determined. Its luminescence properties have also been studied. The title metal carboxylate coordination polymer contains centrosymmetric dimeric units in which each pair of metal ions is linked by a pair of syn-anti carboxylato-O.O' groups, and each pair of such dimeric units is bridged by the backbones of L1 ligands to form infinite double chains in the b direction. These metal carboxylate chains are further cross-linked by hydrogen bonds among both coordinated and discrete nitrate anions, aqua ligands and lattice water molecules to form a three-dimensional network. Luminescent data show that the L1 ligand is a good energy donor and the complex has a relatively long luminescent lifetime.

Jiang-Gao Mao

Papers

First-principles study of electronic structures and nonlinear optical properties of AMoO3(IO3) (A = Li, Rb and Cs) crystals

Syntheses, Crystal Structures and Magnetic Properties of Four CuII-HgII Mixed-Metal Halide Oligomers

Syntheses, crystal structures and luminescent properties of new lanthanide(III) organoarsonates

Pb2Cd(SeO3)2X2 (X = Cl and Br): two halogenated selenites with phase matchable second harmonic generation

Synthesis, crystal structure and luminescence studies of a lanthanide coordination polymer with a new double betaine ligand