Optical limiting non-linear optical activity of hexaaqua copper(II) toluene-4-sulfonate for laser-driven optoelectronic application

Journal of Materials Science: Materials in Electronics - Single crystals of copper (II) complex of P-Toluene sulfonic acid (PTSC) suitable for photonic applications were grown by slow evaporation...     

Strong quantum confinement effect in nanocrystalline cerium oxide

Highly uniform and well-dispersed cerium oxide quantum dots were successfully synthesized by simple precipitation method by using cerium ammonium nitrate and ammonium hydroxide as precursor materials with suitable conditions. The X-ray diffraction pattern indicates the formation of cubic phase CeO₂. The average particle size of cerium oxide from high resolution transmission electron microscopy (HRTEM) was found to be 3 nm. The X-ray photoelectron (XPS) spectrum confirms the presence of Ce³⁺ in CeO₂. Optical studies by UV–vis spectroscopy for the synthesized CeO₂ nanoparticles exhibit a blue shift (E_g = 3.78 eV) with respect to the bulk material (E_g = 3.15 eV) due to quantum confined exciton absorption.     

Collaboration in humanitarian supply chains: an organisational culture framework

The purpose of this study was to determine the impact that institutional logics and, more specifically, organisational culture can have on humanitarian supply chain (HSC) collaboration. A framework was developed that explicates buyer–supplier collaboration in a humanitarian setting. Twenty-nine semi-structured interviews were conducted with buyers and suppliers. The data indicated that in a HSC, collaborative outcomes, such as new product development, inventory management, and product/service delivery, are influenced by the buyers’ and suppliers’ organisational cultures. Based on suppliers’ characteristics, they can be classified as humanitarian suppliers, commercial suppliers, and humanitarian and commercial suppliers. These groups have distinct organisational cultures. An unexpected finding is that suppliers that serve commercial buyers primarily claim to have encountered no issues in supply chain collaboration with humanitarian buyers, although they have different types of organisational cultures. The factors that lead to successful collaboration are identified as trust, commitment, information sharing and mutual respect. Simultaneously, dominant institutional logics are observed in the dyadic relationship.     

Structural and optical characterization of Ni-doped CdS quantum dots

Ni-doped CdS quantum dots have been prepared by chemical precipitation technique. The X-diffraction results indicated that the particle size of Ni-doped CdS nanoparticles is smaller than that of undoped CdS and no secondary phase was observed. The average grain size of the nanoparticles is found to lie in the range of 2.7–4 nm. The compositional analysis results show that Cd, Ni, and S are present in the samples. HRTEM studies reveal that the average particle size of undoped and Ni-doped CdS quantum dots is 2 and 3 nm, respectively. Raman spectra shows that 1LO, 2LO, and 3LO peaks of the Ni-doped CdS samples are slightly red shifted when compared to that of undoped CdS. The absorption edge of Ni-doped CdS nanoparticles is found to shift towards the higher-wavelength (red shift) side when compared to that of undoped CdS and the band gap is observed to lie in the range of 3.79–3.95 eV. This band gap is higher than that of the bulk CdS and is due to quantum confinement effect present in CdS nanoparticles.     

Synthesis,growth, and two-photon absorption induced optical limiting action of cytosinium benzoate single crystal

Two-photon absorption induced optical limiting action was demonstrated in cytosinium benzoate (CB) under nanosecond laser (532 nm, 9 ns, and 10 Hz) excitation. Intensity dependent open aperture Z-scan experiment exposed the presence of reverse saturable absorption ascribed due to sequential two-photon absorption. Initially CB single crystals were grown at room temperature by slow evaporation solution technique. Single crystal XRD shows that CB belongs to monoclinic crystal system with P2₁/c space group. Fourier Transform Infrared spectrum was recorded to identify the presence of functional groups. Thermal studies shows that the crystal is stable upto 168 °C. Vickers microhardness studies confirm that the grown crystal was belongs to soft material category. Etching study shows linear rectangular etch patterns (5 s) and well defined stacking planes (10 s) for water etchant. Optical studies demonstrate that CB crystal possess lower cut-off (287 nm) and moderate linear transmittance in visible region. The optical energy band gap of CB crystal was estimated from photoluminescence studies as 3.1 eV. CB with higher two-photon absorption coefficient (1.26?×?10^–10 m/W) and lower onset limiting threshold (1.92?×?10¹² W/m²) can be a potential candidate for developing laser safety devices under nanosecond green laser excitation regime.

     

Mechanical,thermal and laser damage threshold analyses of II group metal complexes of thiourea

Single crystals of thiourea metal complexes with selected Group II metal ions, Zinc and Cadmium, have been grown by solvent evaporation technique. The crystals grown are bisthiourea zinc chloride (BTZC) and bisthiourea cadmium chloride (BTCC). Following an improved photopyroelectric technique, the thermal transport properties have been determined. It is found that BTCC has a higher heat capacity (304.09 J kg⁻¹ K⁻¹) than BTZC (255.24 J kg⁻¹ K⁻¹), and hence BTCC has better thermal stability. Vicker's microhardness measurements reveal that these materials have reverse indentation size effect and belong to the category of soft materials. Elastic stiffness is found to be higher for BTCC (1.57 GPa) than BTZC (0.76 GPa). The roles of the Group II metal ions in improving the mechanical and thermal stability of the metal complexes are discussed. Multi-shot laser damage studies on these materials reveal that BTCC has a higher laser damage threshold (15 GW cm⁻²) than BTZC (6 GW cm⁻²).     

Third order non-linear optical,diffractional, electrical,laser damage threshold,elemental and surface studies of l-methionine potassium hydrogen phthalate (LMKHP) single crystals

Journal of Materials Science: Materials in Electronics - In this study, semi-organic non-linear optical (NLO) crystal l-methionine potassium hydrogen phthalate (LMKHP) was prepared via the solvent...     

Thulium-doped barium tellurite glasses: structural,thermal, linear,and non-linear optical investigations

Journal of Materials Science: Materials in Electronics - A systematic study of structural, thermal, linear, and non-linear optical properties on...