Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Although known since the late 19th century, organic–inorganic perovskites have recently received extraordinary research community attention because of their unique physical properties, which make them promising candidates for application in photovoltaic (PV) and related optoelectronic devices. This review will explore beyond the current focus on three-dimensional (3-D) lead(II) halide perovskites, to highlight the great chemical flexibility and outstanding potential of the broader class of 3-D and lower dimensional organic-based perovskite family for electronic, optical, and energy-based applications as well as fundamental research. The concept of a multifunctional organic–inorganic hybrid, in which the organic and inorganic structural components provide intentional, unique, and hopefully synergistic features to the compound, represents an important contemporary target.

Organic–Inorganic Perovskites: Structural Versatility for Functional Materials Design

The prospects for light-emitting diodes and lasers based on perovskite materials are reviewed. The field of solution-processed semiconductors has made great strides; however, it has yet to enable electrically driven lasers. To achieve this goal, improved materials are required that combine efficient (>50% quantum yield) radiative recombination under high injection, large and balanced charge-carrier mobilities in excess of 10 cm2 V−1 s−1, free-carrier densities greater than 1017 cm−3 and gain coefficients exceeding 104 cm−1. Solid-state perovskites are — in addition to galvanizing the field of solar electricity — showing great promise in photonic sources, and may be the answer to realizing solution-cast laser diodes. Here, we discuss the properties of perovskites that benefit light emission, review recent progress in perovskite electroluminescent diodes and optically pumped lasers, and examine the remaining challenges in achieving continuous-wave and electrically driven lasing.

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Perovskite photonic sources

Drugs with low water solubility are predisposed to low and variable oral bioavailability and, therefore, to variability in clinical response. Despite significant efforts to "design in" acceptable developability properties (including aqueous solubility) during lead optimization, approximately 40% of currently marketed compounds and most current drug development candidates remain poorly water-soluble. The fact that so many drug candidates of this type are advanced into development and clinical assessment is testament to an increasingly sophisticated understanding of the approaches that can be taken to promote apparent solubility in the gastrointestinal tract and to support drug exposure after oral administration. Here we provide a detailed commentary on the major challenges to the progression of a poorly water-soluble lead or development candidate and review the approaches and strategies that can be taken to facilitate compound progression. In particular, we address the fundamental principles that underpin the use of strategies, including pH adjustment and salt-form selection, polymorphs, cocrystals, cosolvents, surfactants, cyclodextrins, particle size reduction, amorphous solid dispersions, and lipid-based formulations. In each case, the theoretical basis for utility is described along with a detailed review of recent advances in the field. The article provides an integrated and contemporary discussion of current approaches to solubility and dissolution enhancement but has been deliberately structured as a series of stand-alone sections to allow also directed access to a specific technology (e.g., solid dispersions, lipid-based formulations, or salt forms) where required.

Strategies to Address Low Drug Solubility in Discovery and Development

Organic-inorganic hybrid perovskites have cemented their position as an exceptional class of optoelectronic materials thanks to record photovoltaic efficiencies of 22.1%, as well as promising demonstrations of light-emitting diodes, lasers, and light-emitting transistors. Perovskite materials with photoluminescence quantum yields close to 100% and perovskite light-emitting diodes with external quantum efficiencies of 8% and current efficiencies of 43 cd A(-1) have been achieved. Although perovskite light-emitting devices are yet to become industrially relevant, in merely two years these devices have achieved the brightness and efficiencies that organic light-emitting diodes accomplished in two decades. Further advances will rely decisively on the multitude of compositional, structural variants that enable the formation of lower-dimensionality layered and three-dimensional perovskites, nanostructures, charge-transport materials, and device processing with architectural innovations. Here, the rapid advancements in perovskite light-emitting devices and lasers are reviewed. The key challenges in materials development, device fabrication, operational stability are addressed, and an outlook is presented that will address market viability of perovskite light-emitting devices.

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Perovskite Materials for Light-Emitting Diodes and Lasers.

C.N.R. Rao, M.M. Seikh, C. Narayana: Spin-State Transition in LaCoO3 and Related Materials .- H.A. Goodwin: Spin Crossover in Cobalt(II) Systems .- Y. Garcia, P.Gutlich: Thermal Spin Crossover in Mn(II), Mn(III) Cr(II) and Co(III) Coordination Compounds .- D.N. Hendrickson, C.G. Pierpont: Valence Tautomeric Transition Metal Complexes .- P. Guionneau, M. Marchivie, G.Bravic, J.-F. Letard, D. Chasseau: Structural Aspects of Spin Crossover. Example of the [Fe(II)Ln(NCS)2] Complexes .- J. Kusz, P. Gutlich, H. Spiering: Structural Investigations of Tetrazole Complexes of Iron(II) .- A. Hauser: Light-Induced Spin Crossover and the High-Spin Low-Spin Relaxation .- F. Varret, K. Boukheddaden, E. Codjovi, C. Enachescu, J. Linares: On the Competition Between Relaxation and Photoexcitations in Spin Crossover Solids under Continuous Irradiation .- P. Gutlich: Nuclear Decay Induced Excited Spin State Trapping (NIESST) .- M.-L. Boillot, J. Zarembowitch, A. Sour: Ligand-Driven Light-Induced Spin Change (LD-LISC): A Promising Photomagnetic Effect

Spin Crossover in Transition Metal Compounds I

The performance of hybrid organic perovskite (HOP) for solar energy conversion is driving a renewed interest in their light emitting properties. The recent observation of broad visible emission in layered HOP highlights their potential as white-light emitters. Improvement of the efficiency of the material requires a better understanding of its photophysical properties. We present in-depth experimental investigations of white-light (WL) emission in thin films of the (C6H11NH3)2PbBr4. The broadband, strongly Stokes shifted emission presents a maximum at 90 K when excited at 3.815 eV, and below this temperature coexists with an excitonic edge emission. X-rays and calorimetry measurements exclude the existence of a phase transition as an origin of the thermal behavior of the WL luminescence. The free excitonic emission quenches at low temperature, despite a binding energy estimated to 280 meV. Time-resolved photoluminescence spectroscopy reveals the multicomponent nature of the broad emission. We analyzed the...

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Optical Investigation of Broadband White-Light Emission in Self-Assembled Organic–Inorganic Perovskite (C6H11NH3)2PbBr4

We have analyzed an Ising-like model, in the mean-field approach, involving two “antiferromagnetically” coupled sublattices. This model simulates the so-called “two-step” spin-crossover transition, for which a precise definition is given. If both sublattices are equivalent, it implies a spontaneous breaking of symmetry which may occur within a temperature range limited by two “Neel temperatures”. It, also predicts a simultaneous reversal of the magnetization of the sublattices (if they are unequivalent) at a “characteristic” value of temperature. These features are analyzed simultaneously with some details. The present model fits and explains well the available experimental data concerning [ Fe(2-pic)3] Cl2- EtOH and FeII[ 5NO2 – sal – N(1, 4, 7, 10)] .

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Ising-like model for the two-step spin-crossover

We investigate the behaviour of photo-excitable, bistable systems, under permanent light irradiation, in presence of relaxation towards the non-excited state. Cooperativity causes bistability of the steady state, leading to light-induced thermal and optical hysteresis (LITH and LIOH). The light-induced instability is expected to induce demixtion, i.e. the coexistence of domains of the two stable steady states. Such effects are evidenced by magnetic and reflectivity measurements on the spin-crossover solid solution: [Fex , with x= 0.3, 0.5, 0.85. Experimental data are in quantitative agreement with a simple macroscopic model which includes a non-linear relaxation term in the master equation.

Light-induced bistability in spin transition solids leading to thermal and optical hysteresis

A stochastic cooperative dynamics of the Ising-like Hamiltonian describing the equilibrium properties of the spin-crossover solids is derived from the Glauber approach, where an appropriate choice of the microscopic dynamics is made with respect to experimental features. The model is used here in the mean-field approach, and supports the previous phenomenological dynamic equations. The expected sigmoidal shape of the relaxation curves from high-spin to low-spin states after photoexcitation is obtained, and the kinetic character of the thermal hysteresis loops (inherent to the experimental data) is properly accounted for.

Kamel Boukheddaden

Papers

Spin Crossover in Transition Metal Compounds I

Optical Investigation of Broadband White-Light Emission in Self-Assembled Organic–Inorganic Perovskite (C6H11NH3)2PbBr4

Ising-like model for the two-step spin-crossover

Light-induced bistability in spin transition solids leading to thermal and optical hysteresis

Dynamical model for spin-crossover solids. I. Relaxation effects in the mean-field approach