The Determination of the Mechanical, Optoelectronic, Structural and Transport Attributes of Double Perovskite AInGaBr (A=K, Rb, Cs) Halides for Renewable Energies: A DFT Study.

Safer and more environmentally friendly alternatives to lead-based perovskites include lead-free halide perovskites, which retain good optoelectronic capabilities while reducing environmental toxicity. They also align better with ecological and regulatory standards for green technologies. In this manuscript, we have presented the first principles analysis of the physical traits of AInGaBr (A=K, Rb, Cs).

Electrical transport properties of [(1 - )succinonitrile:poly(ethylene oxide)]-LiCFSO-Co[tris-(2,2'-bipyridine)](TFSI)-Co[tris-(2,2'-bipyridine)](TFSI) solid redox mediators.

A solid redox mediator (solid electrolyte) with an electrical conductivity () greater than 10 S cm is an essential requirement for a dye-sensitized solar cell in the harsh weather of Gulf countries. This paper reports the electrical properties of solid redox mediators prepared using highly dissociable ionic salts: Co[tris-(2,2'-bipyridine)](TFSI), Co[tris-(2,2'-bipyridine)](TFSI), and LiCFSO as a source of Co, Co, and Li ions, respectively, in a solid matrix: [(1 - )succinonitrile:poly(ethylene oxide)], where = 0, 0.5, and 1 in weight fraction.

Electronic Structure and Optical Properties of Inorganic and CsPbX (X = Cl, Br, I) Perovskite: A Theoretical Understanding from Density Functional Theory Calculations.

In this study, we investigated the optoelectronic properties of cubic () and orthorhombic () CsPbX (X = I, Br, and Cl). We utilized the full potential linear augmented plane wave method, which is implemented in the WIEN2k code, to facilitate the investigation. Different exchange potentials were used to analyze the optoelectronic behavior using the available density functional theory methods.

Surface Passivation for Promotes Bi-Excitonic Amplified Spontaneous Emission in CsPb(Br/Cl) Perovskite at Room Temperature.

Perovskite-type lead halides exhibit promising performances in optoelectronic applications, for which lasers are one of the most promising applications. Although the bulk structure has some advantages, perovskite has additional advantages at the nanoscale owing to its high crystallinity given by a lower trap density. Although the nanoscale can produce efficient light emission, its comparatively poor chemical and colloidal stability limits further development of devices based on this material.

Successful Growth of TiO Nanocrystals with {001} Facets for Solar Cells.

The growth of nanocrystals (NCs) from metal oxide-based substrates with exposed high-energy facets is of particular importance for many important applications, such as solar cells as photoanodes due to the high reactivity of these facets. The hydrothermal method remains a current trend for the synthesis of metal oxide nanostructures in general and titanium dioxide (TiO) in particular since the calcination of the resulting powder after the completion of the hydrothermal method no longer requires a high temperature. This work aims to use a rapid hydrothermal method to synthesize numerous TiO-NCs, namely, TiO nanosheets (TiO-NSs), TiO nanorods (TiO-NRs), and nanoparticles (TiO-NPs).

Structural, Thermal, and Electrical Properties of Poly(Ethylene Oxide)-Tetramethyl Succinonitrile Blend for Redox Mediators.

An all-solid−state dye-sensitized solar cell is one of the non-fossil fuel-based electrochemical devices for electricity generation in a high-temperature region. This device utilizes a redox mediator, which is a fast ion-conducting solid polymer electrolyte (SPE). The SPE makes the device economical, thinner, and safer in high-temperature regions.

Amplified Spontaneous Emission from Thermally Evaporated High-Quality Thin Films of CsPb(BrY) (Y = I, Cl) Perovskites.

As a wavelength-tunable lasing material, perovskites are now generating a lot of scientific attention. Conventional solution-processed CsPbX perovskite films sometimes suffer unavoidable pinhole defects and poor surface morphology, severely limiting their performance on amplified spontaneous emission (ASE) and lasing application. Herein, a thermal evaporation approach is explored in our work to achieve a uniform and high-coverage CsPb(BrY) (Y = I, Cl) perovskites polycrystalline thin film.

Electrical Transport, Structural, Optical and Thermal Properties of [(1-)Succinonitrile: PEO]-LiTFSI-Co(bpy)(TFSI)-Co(bpy)(TFSI) Solid Redox Mediators.

The solar cell has been considered one of the safest modes for electricity generation. In a dye-sensitized solar cell, a commonly used iodide/triiodide redox mediator inhibits back-electron transfer reactions, regenerates dyes, and reduces triiodide into iodide. The use of iodide/triiodide redox, however, imposes several problems and hence needs to be replaced by alternative redox.

Tetramethyl Succinonitrile as a Solid Plasticizer in a Poly(ethylene oxide) -LiI-I Solid Polymer Electrolyte.

Dye-sensitized solar cell (DSSC) is a promising alternative to the commercially available amorphous silicon-based solar cell because of several advantageous properties. A DSSC with a fast ion conducting solid polymer electrolyte is required for the arid atmosphere of Gulf countries. In this work, a new matrix, poly(ethylene oxide)-tetramethyl succinonitrile blend to synthesize a blend-LiI-I solid polymer electrolyte for the DSSC application has been proposed.

Density Functional Theory Analysis of Structural, Electronic, and Optical Properties of Mixed-Halide Orthorhombic Inorganic Perovskites.

Inorganic metal-halide perovskites hold a lot of promise for solar cells, light-emitting diodes, and lasers. A thorough investigation of their optoelectronic properties is ongoing. In this study, the accurate modified Becke Johnson generalized gradient approximation (mBJ-GGA) method without/with spin orbital coupling (SOC) implemented in the WIEN2k code was used to investigate the effect of mixed I/Br and Br/Cl on the electronic and optical properties of orthorhombic CsPb(I Br ) and CsPb(Br Cl ) perovskites, while the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) method was used to investigate their structural properties.

Enhancement of Light Amplification of CsPbBr Perovskite Quantum Dot Films via Surface Encapsulation by PMMA Polymer.

Photonic devices based on perovskite materials are considered promising alternatives for a wide range of these devices in the future because of their broad bandgaps and ability to contribute to light amplification. The current study investigates the possibility of improving the light amplification characteristics of CsPbBr perovskite quantum dot (PQD) films using the surface encapsulation technique. To further amplify emission within a perovskite layer, CsPbBr PQD films were sandwiched between two transparent layers of poly(methyl methacrylate) (PMMA) to create a highly flexible PMMA/PQD/PMMA waveguide film configuration.

Achieving Optical Gain of the CsPbBr Perovskite Quantum Dots and Influence of the Variable Stripe Length Method.

High-quality inorganic cesium lead halide perovskite quantum dot (CsPbBr PQD) thin films were successfully deposited directly from a powdered source and used as an active laser medium following the examination of their distinctive surface and structural properties. To determine the suitability of the CsPbBr PQDs as an active laser medium, amplified spontaneous emission (ASE) and optical gain properties were investigated under picosecond pulse excitation using the variable stripe length (VSL) method. The thin film of CsPbBr PQDs has exhibited a sufficient value of the optical absorption coefficient of ∼0.

Single-Source Thermal Evaporation Growth and the Tuning Surface Passivation Layer Thickness Effect in Enhanced Amplified Spontaneous Emission Properties of CsPb(BrCl) Perovskite Films.

High-quality inorganic cesium lead halide perovskite CsPb(BrCl) thin films were successfully achieved through evaporation of the precursors and deposition sequentially by a single-source thermal evaporation system. The different melting points of the precursors were enabled us to evaporate precursors one by one in one trip. The resulting films through its fabrication were smooth and pinhole-free.

Ultra-Stable Polycrystalline CsPbBr Perovskite-Polymer Composite Thin Disk for Light-Emitting Applications.

Organic-inorganic halide organometal perovskites have demonstrated very promising performance in optoelectronic applications, but their relatively poor chemical and colloidal stability hampers the further improvement of devices based on these materials. Perovskite material engineering is crucial for achieving high photoluminescence quantum yields (PLQYs) and long stability. Herein, these goals are attained by incorporating bulk-structure CsPbBr, which prevents colloidal degradation, into polymethyl methacrylate (PMMA) polymer in thin-disk form.

Fabrication of Thin Films from Powdered Cesium Lead Bromide (CsPbBr) Perovskite Quantum Dots for Coherent Green Light Emission.

High-quality thin films were obtained directly by spin-coating glass substrates with suspensions of powdered cesium lead bromide (CsPbBr) perovskite quantum dots (PQDs). The structural properties of the films were characterized via transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis, and atomic force microscopy (AFM). The crystal structure of the CsPbBr PQDs was unique.

Structural, Electronic, and Optical Properties of CsPb(BrCl) Perovskite: First-Principles Study with PBE-GGA and mBJ-GGA Methods.

The effect of halide composition on the structural, electronic, and optical properties of CsPb(BrCl) perovskite was investigated in this study. When the chloride (Cl) content of x was increased, the unit cell volume decreased with a linear function. Theoretical X-ray diffraction analyses showed that the peak (at 2θ = 30.

Triplet Energy Transfer Mechanism of Ternary Organic Hybrid Thin Films of PFO/MEH-PPV/CsPbBr Perovskite Quantum Dots.

The triplet energy transfer mechanism of novel poly(9,9-di--octylflourenyl-2,7-diyl) (PFO)/poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)/CsPbBr perovskite quantum dot (PQD) hybrid thin films was comprehensively investigated. The concentrations of PFO and MEH-PPV in all the specimens were fixed, while the PQD content was varied with various weight ratios and premixed by a solution blending method before it was spin-coated onto glass substrates. The triplet non-radiative Förster resonance energy transfers (FRETs) in the PFO/MEH-PPV/PQDs ternary blend, the dual FRET from PFO to both PQDs and MEH-PPV, and the secondary FRET from PQDs to MEH-PPV were observed.

Reducing Amplified Spontaneous Emission Threshold in CsPbBr Quantum Dot Films by Controlling TiO Compact Layer.

Amplified spontaneous emission (ASE) threshold in CsPbBr3 quantum dot films is systematically reduced by introducing high quality TiO2 compact layer grown by atomic-layer deposition. Uniform and pinhole-free TiO2 films of thickness 10, 20 and 50 nm are used as a substrates for CsPbBr3 quantum dot films to enhance amplified spontaneous emission performance. The reduction is attributed indirectly to the improved morphology of TiO2 compact layer and subsequently CsPbBr3 active layer as grown on better quality substrates.

Density Functional Study of Cubic, Tetragonal, and Orthorhombic CsPbBr Perovskite.

Cesium lead bromide (CsPbBr) perovskite has recently gained significance owing to its rapidly increasing performance when used for light-emitting devices. In this study, we used density functional theory to determine the structural, electronic, and optical properties of the cubic, tetragonal, and orthorhombic temperature-dependent phases of CsPbBr perovskite using the full-potential linear augmented plane wave method. The electronic properties of CsPbBr perovskite have been investigated by evaluating their changes upon exerting spin-orbit coupling (SOC).

Rapid Room-Temperature Synthesis of Mesoporous TiO Sub-Microspheres and Their Enhanced Light Harvesting in Dye-Sensitized Solar Cells.

Submicron sized mesoporous spheres of TiO have been a potential alternative to overcome the light scattering limitations of TiO nanoparticles in dye-sensitized solar cells (DSSCs). Currently available methods for the growth of mesoporous TiO sub-microspheres involve long and relatively high temperature multi-stage protocols. In this work, TiO mesoporous sub-microspheres composed of ~5 nm anatase nanocrystallites were successfully synthesized using a rapid one-pot room-temperature CTAB-based solvothermal synthesis.

One step synthesis of NiO nanoparticles via solid-state thermal decomposition at low-temperature of novel aqua(2,9-dimethyl-1,10-phenanthroline)NiCl2 complex.

[NiCl2(C14H12N2)(H2O)] complex has been synthesized from nickel chloride hexahydrate (NiCl2·6H2O) and 2,9-dimethyl-1,10-phenanthroline (dmphen) as N,N-bidentate ligand. The synthesized complex was characterized by elemental analysis, infrared (IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and differential thermal/thermogravimetric analysis (TG/DTA). The complex was further confirmed by single crystal X-ray diffraction (XRD) as triclinic with space group P-1.

Photoluminescence spectra of CdSe/ZnS quantum dots in solution.

The spectral properties of CdSe/ZnS core-shell quantum dots (QDs) of 3 nm size have been studied under different organic solvents, concentrations and temperatures. Our results showed that the absorption spectra of CdSe/ZnS in benzene have two humps; one around 420 nm and another at 525 nm, with a steady increase in absorption along UV region, and the absorption spectral profile under a wide range of concentrations did not change. On the other hand, the photoluminescence (PL) spectra of CdSe/ZnS in benzene showed two bands one around 375 nm and the other around 550 nm.

Facile synthesis of water-soluble luminescent mesoporous Tb(OH)3@SiO2 core-shell nanospheres.

Luminescent mesoporous Tb(OH)3@SiO2 core-shell nanospheres were synthesized through W/O microemulsion process at ambient temperature. The negatively charged silica favors a coating of the positively charged Tb3+ composite. Thus, silicon layer was adsorbed on the surface of Tb(OH)3 groups to form Tb-O-Si through electrostatic interaction.

Fluorescence spectra of blood and urine for cervical cancer detection.

In the current study, the fluorescence emission spectra (FES) and Stokes shift spectra (SSS) of blood and urine samples of cervical cancer patients were obtained and compared to those of normal controls. Both spectra showed that the relative intensity of biomolecules such as porphyrin, collagen, Nicotinamide adenine dinucleotide, and flavin were quite out of proportion in cervical cancer patients. The biochemical mechanism for the elevation of these fluorophores is not yet definitive; nevertheless, these biomolecules could serve as tumor markers for diagnosis, screening, and follow-up of cervical cancers.

Amplified spontaneous emission spectra from the superexciplex of coumarin 138.

In this report the dual amplified spontaneous emission (ASE) characteristics of coumarin 138 (C(138)) had been studied, under different solvent environments. The results obtained were compared with coumarin 461 (C(461)) and coumarin 450 (C(450)), which have closely related structure. The results showed that all these dyes could produce ASE from superexciplex - a new molecular species - formed only under high inversion densities, obtainable by pulsed laser excitation.