Solid-state Bulk Research Articles

Michael James Stowell. 10 July 1935—27 February 2022

Mike Stowell was a Bristol physicist turned metallurgist who led the development of practical aluminium-based superplastic alloys by showing how to retain grains small enough, at temperatures high enough, to allow almost unlimited shape changes in forming operations. He can be regarded as the father of SUPRAL alloys, as these are now called. At the Tube Investment laboratory in Hinxton Hall, Essex, he led teams that made effective use of the novel electron-optical equipment invented there to solve numerous fascinating problems of technical importance, among them the sequence of growth by evaporation of thin metallic films and the mechanisms controlling the precipitation of graphite in cast iron. He was dedicated to science at the heart of industrial metallurgy, so that when the laboratory closed, rather than retire, he became research director at Alcan, interacting with a laboratory in Italy as well as managing disparate laboratories in England and Canada to develop coatings for the electrodes used in aluminium production. He was a founder member of what we now know as the ‘Cambridge Phenomenon’, the close interaction between innovative, high-tech industry and the university. In connection with these activities, he made long-lasting fundamental contributions to the understanding of precipitation both of two-dimensional islands in the growth of thin films and in three dimensions in the bulk solid state.

The emerging field of block copolymer self-assembly-directed quantum materials

The area of functional materials derived from block copolymers (BCPs) as structure-directing agents for various inorganic materials has seen substantial growth as a result of the immense scientific as well as technological promise associated with such hybrid materials. The convergence of BCP self-assembly with the fast-growing field of quantum materials now promises solution-based synthetic approaches to classes of materials that to date are dominated by stringent high-vacuum physical deposition techniques and bulk solid state chemical reactions. Moreover, the ensuing periodic nano- and mesostructures, a characteristic of BCP self-assembly, offer a unique platform for manipulating quantum-level properties, in turn resulting in substantial changes of macroscopic properties. This article will make a case for, review the existing work of, and provide our perspectives on this emerging field of block copolymer self-assembly directed quantum materials.

A rigid calcium 2-ethylhexylphosphate one-dimensional polymer: synthesis, structure, thermal behaviour and decomposition chemistry.

The reactivity of two different phosphate esters has been explored with calcium ions. The reaction of calcium oxide with a mixture of mono/bis 2-ethylhexyl phosphate and 1,10-phenanthroline leads to the formation of the 1-D polymer [(phen)Ca(ehpH)2]n (1). On the other hand, the reaction of Ca(OAc)2 with trimethyl phosphate in the presence of 1,10-phenanthroline however yields needle-shaped colourless crystals of [(phen)Ca(OAc)2]n (2). Compounds 1 and 2 have been characterized by various spectroscopic and analytical techniques. The solid-state structures have been determined by single crystal X-ray diffraction studies. The arrangement of rigid and flexible parts in 1 makes it an interesting compound to be studied for its thermal behaviour. DSC experiments performed above and below room temperature reveal thermal transitions in both the ranges, where below room temperature transition is prominent. A combination of variable temperature powder and single crystal X-ray diffraction experiments provides further insights into these transitions. Solid-state bulk thermolysis of 1 at 500 °C leads to an amorphous material contaminated with graphitic carbon which upon further heating to 600 °C produces crystalline α-Ca(PO3)2.

A corrugated epsilon-nearzero saturable absorber for a high-performance 1.3 μm solid-state bulk laser.

Epsilon-near-zero (ENZ) materials with vanishing permittivity exhibit unprecedented optical nonlinearity within subwavelength propagation lengths in the ENZ region, making them promising photoelectric materials that have achieved exciting results in ultrafast pulse laser modulations. In this study, we fabricated a novel saturable absorber (SA) based on a corrugated indium tin oxide (CITO) film with a symmetrical geometry using a low-cost self-assembly process. The strong saturable absorption of the CITO film triggered by the ENZ effect at normal incidence was comparable to that of the planar indium tin oxide (ITO) film at an optimal 60° incidence (TM polarization) at 1340 nm. In addition, the strong nonlinear optical properties of the CITO film were not limited by the incident angle and polarization state of the pump laser over a wide range of 0-20°. Benefiting from the excellent saturable absorption of CITO-based SA at normal incidence, a Q-switching operation with CITO-based SA at 1.34 μm was achieved in a Nd:YVO4 solid-state laser system, obtaining pulses of a duration of 85.6 ns, which was one order of magnitude narrower than that of the planar ITO-based SA. This study presents a new strategy for developing high-performance ENZ-based SAs and ultrafast lasers.

Femtosecond Mode-Locked Yb:KYW Laser Based on InP Nanowire Saturable Absorber

In this letter, indium phosphide (InP) nanowires (NWs) are fabricated by Au-nanoparticle assisted vapor-liquid-solid method and applied as a saturable absorber (SA) for continuous-wave (CW) mode-locked femtosecond Yb:KYW bulk laser. I-scan method was used to characterize the saturable absorption properties of the prepared InP NWs SA. Pulses as short as 394 fs with the repetition rate of 41.5 MHz and maximum average output power of 315 mW are achieved. To the best of our knowledge, this is the first demonstration of InP NWs working as SA for the fs-pulse generation in the solid-state bulk laser. The results indicate that InP NWs are a promising SA candidate for applications in ultrafast photonic devices.

Influence of speciation distribution and particle size on heavy metal leaching from MSWI fly ash.

Fly ash from municipal solid waste incineration (MSWI-FA) contains leachable heavy metals. In the present study the correlations between heavy metal content, particle size, speciation distribution with respect to water leaching are investigated, using a combination of solid-state bulk analytical techniques, leaching treatments, sequential extractions and thermodynamic geochemical modelling. Among the analyzed heavy metals, Zn and Pb are the most abundant in any grain size class, followed by Cu, Cr, Cd and Ni, with concentration that tends to increase with a decrease of the grain size. The phase composition is constituted of salt (halite, sylvite, anhydrite and syngenite), which provide the main minerals regardless of the particle size class; calcite, quartz and gehlenite occur in comparatively lower amounts, while 50% wt is composed of amorphous fraction. Heavy metal leaching is strongly correlated to speciation distribution, and in particular to the fraction (F1) associated with salt, carbonate and weak surface sorption. Leaching from speciation due to surface complexation on Al/Fe (hydr)oxide becomes relevant at acidic regime. Particle size and heavy metal content, in turn, moderately correlate with leaching. The F1-speciation as a function of particle size does not exhibit a definite trend shared by all heavy metals under investigation. This suggests that i) differences in speciation distribution, rather than bare heavy metal content or particle size, govern leaching from MSWI-FA; ii) F1 can be regarded as a marker of the potential heavy metal leaching; iii) a comparatively modest efficiency in managing MSWI-FA is expected from grain size separation strategies.

Nanosecond and femtosecond lasers based on black arsenic-phosphorus alloys saturable absorber

In this paper, the high-repetition-rate passively Q-switched (PQS) and the femtosecond continuous-wave mode-locked (CWML) lasers are successfully obtained with 2D black arsenic-phosphorus (b-AsP) nanosheets as saturable absorber (SA) at 1 μm for the first time, to the best of our knowledge. The saturable absorption properties and ultrafast carrier dynamics of the 2D b-AsP SA are explored by Z-scan and pump-probe techniques. Moreover, according to the measurement of desired nonlinear optical characteristics of the relaxation time of 27 ps and the modulation depth of 7.14%, the PQS and CWML lasers are demonstrated with the highest repetition rate of 2.26 MHz in the PQS laser and the pulse width of 470 fs in the CWML laser. The results show 2D b-AsP SA has enormous potential for pulse modulation in solid-state bulk lasers.

Effectiveness of an additively manufactured porous layer in dissimilar solid-state bulk joining of additively manufactured maraging steel and conventional AISI410 steel

Solid-state bulk joining of additively manufactured maraging steel and commercially available martensitic stainless steel (AISI410) specimens in a cylindrical shape is accomplished through electrically assisted pressure joining (EAPJ). The cylindrical maraging steel specimen is fabricated to have a porous layer on the joining side by selective laser melting additive manufacturing. During EAPJ, the porous layer, which serves as an interlayer with locally increased electrical resistance due to geometrically induced defects (pores), significantly and locally increases the maximum temperature while the joining load is dramatically decreased. The microstructure evolution suggests that grain refinement occurs on both the maraging steel and AISI410 sides due to recrystallization. The high residual stress induced during additive manufacturing of maraging steel specimens is significantly released during EAPJ. Martensite formation in the AISI410 steel and the reverted austenite in the maraging steel are characterized by the grain average image quality. Tensile tests show that the fracture always occurs in the transition region between the heat-affected region and the unaffected base metal region. The present study demonstrates that bulk joining of additively manufactured components and conventional components can be more easily and effectively achieved with the use of an additively manufactured porous layer, even for dissimilar material combinations. • AMed maraging steel and conventional AISI410 steel were solid-state joined. • The temperature was locally controlled by the AMed porous layer. • The high residual stress of AMed maraging steel was released during joining. • Microstructure evolution during joining was characterized by EBSD. • Base metal fracture in AISI410 side occurred during tension test.

Randomized solid state bulk functionalization of aramid fiber pulp and its application in elastomer compositions

AbstractN‐oxydiethylene‐2‐benzothiazole sulphenamide (NOBS) dispersed in an inert (saturated main chain) rubber matrix (ethylene‐co‐propylene‐diene monomer [EPDM], as carrier to be dispersed later in a predetermined lower quantities) containing definite amount of pre‐dried aramid fiber pulp (AP) was subjected to internal thermal influence as heated through dielectric‐dielectric interaction in a laboratory microwave oven. The reactions of NOBS with aramid fiber pulp (on the surface and in the bulk) were characterized using XPS, TGA, FTIR, SEM, and mechanical properties. The objective was to confirm the efficacy of dielectric heating in situ and to promote functionality for bonding with rubber. The functionalization was considered to be provided by NOBS. One such chemical modification was found to be the generation of free ends in the AP and it was characterized by XPS. At the same time, there was no thermal degradation as confirmed from TGA studies. The rubber‐AP masterbatch (as previously prepared was dispersed) in different proportions in Butadiene‐co‐acrylonitrile rubber (NBR) and various characterizations related to plain rubber compound and in the cross linked states including fluid barrier properties and spring characteristics were found to record a significant improvement. The SEM micrographs showed that the fiber‐rubber cohesion and the rubber‐AP interaction are enhanced due to the proposed dielectric heating induced functionalization of AP.

Investigating the Bulk Level Optoelectronic Characteristics of 10-(1,3-Dithiol-2-Ylidene)Anthracene Based Light Harvesters

Various optoelectronic properties of 10-(1,3-Dithiol-2-ylidene)anthracene based organic light harvesters were probe at solid state bulk surface. Effect of diverse conjugated π-donor-acceptor bridge, 3,4-ethylenedioxythiophene in Comp3 and phenyl for Comps1 and 2, along with two set of electron acceptor entity, an ester moiety for Comp1, a dicyanovinylene moiety for Comp2 and Comp3 was explored on various properties. The 3,4-ethylenedioxythiophene as conjugated π-bridge boost the dielectric constants, conductivity, refractive index and extinction coefficient values significantly. The dicyanovinylene is favorable than the ester group as prior moiety contributes to the p-orbitals from −2.0 to −4.0 eV. The solid states density, relative permittivity’s, extinction coefficient, indices of refraction, reflectance, and electrical conductivity displayed that anthracene derivatives may act as proficient objects in multi-purpose organic semiconductors.

Modulation of the Molecular Structure of Tri-aryl Amine Fibrils in Hybrid Poly[vinyl chloride] Gel/Organogel Systems

This paper reports on the thermodynamics through mapping out temperature–concentration phase diagrams and the molecular structure and the morphology of binary organogels prepared with trisamide triarylamine (TATA) in tetrachloroethane and on their ternary thermoreversible hybrid gels formed with polyvinyl chloride (PVC). For low PVC contents, the TATA organogel moiety behaves as in the binary systems, while for higher PVC contents, the thermal behavior is significantly altered with the appearance of a nonvariant event. The molecular structure of the TATA assemblies is compared with that observed in the bulk solid state. Three molecular packings are observed in the bulk, whose crystalline lattices are tentatively derived. Structure I obtained after the crystallization–purification process is seen to transform at higher temperature into structure II. By cooling, structure III is obtained, which transforms reversibly into structure II on heating. The metastability of structure I leads one to contemplate the possible formation of molecular compounds during the crystallization–purification process in the presence of chlorinated solvents, the more so as the crystalline structures in the gels turn out to exhibit high similarities. Finally, the morphology observation reveals that the TATA fibrils and the PVC matrix can be well identified for low PVC contents, while for higher PVC contents, one essentially observes the TATA fibrils

A novel method for spatially-resolved thermal conductivity measurement by super-resolution photo-activated infrared imaging

Thermal conductivity measurements play a crucial role in most areas of the applied physical sciences, thereby constantly demanding for new non-invasive methods capable of providing high-resolution spatial mapping of absolute thermal conductivities on heterogeneous samples ranging from solid-state bulk materials to low-dimensionality structures. In this work, we lay the theoretical foundations and provide the experimental demonstration of a novel method for quantitative thermal conductivity mapping at tunable ∼10-μm resolution, by non-contact infrared photo-activated thermography. Starting from Fourier’s heat transfer law, we surmise a universal dependence of the thermal response of a laser-irradiated sample on its thermal conductivity, irrespectively of density and specific heat capacity. We demonstrate such a dependence over the three conductivity decades 0.1–100 W/mK by finite-element numerical simulations, and exploit it for proof-of-principle single-point thermal conductivity measurements on both thermally thick and thermally thin reference solid samples. We exemplify the feasibility of space-resolved measurements on eighteenth-century tin organ pipe fragments, where the product of the thermal conductivity times the sample thickness, imaged at 40-μm sub-diffraction resolution, is pointed out as a relevant parameter for the non-destructive characterization of the sample conservation state. By coupling temperature maps with the extraction of thermal properties at high spatial resolution, our approach significantly expands the capability of state-of-the-art infrared imaging technology in fully capturing the compositional heterogeneity and/or functional state of the imaged materials.

Exploring the electron-hole transport nature and optoelectronic properties of 4-nitro-4′-amino-azobenzene-based dyes

Charge transport and electronic properties of 4-nitro-4′-amino-azobenzene compounds with donor-acceptor backbone were examined at the molecular level. Optical properties of all the studied six azobenzene dyes were also explored at the solid-state bulk level, i.e., dielectric constants, conductivity, refractive index, and extinction coefficient values. The introduction of benzyl group enhances whereas propanenitrile diminishes the values for real and imaginary dielectric functions. Moreover, the substitution of 3-methoxy-3-oxopropyl and propanenitrile at amino group decreases the real conductivity values; however, bis(3-methoxy-3-oxopropyl) improves these values. These 4-nitro-4′-amino-azobenzene compounds showed good refractive indices in the energy range 0–2 eV which revealed that these dyes would be efficient to generate healthier outputs with lower energy inputs. The effect of substituents was also investigated on transfer integrals, frontier molecular orbitals (FMOs), reorganization energies, electron affinity (EA), and ionization energy (IE). The ground-state geometries were optimized by density functional theory at B3LYP/6-31G** level to probe the molecular level properties. The same level of theory was used for the cation and anion optimizations. The hole and electron transfer nature of azo dyes was investigated by evaluating the electron/hole transfer integrals (Velectron/Vhole) as well as hole and electron reorganization energy values. The results exposed that superior Vhole values of Azo2 and Azo4 might lead to these dyes as p-type contenders. Moreover, larger Velectron values of Azo1, Azo3, Azo5, and Azo6 might lead to these dyes as n-type competitors. These results revealed that inspected Azo dyes would be able to serve as competent hole and electron transfer materials within versatile organic semiconductors.

Thin-film growth of MAX phases as functional materials

Abstract Layered nanolaminate ternary carbides, nitrides and carbonitrides with general formula Mn+1AXn or MAX (n = 1, 2, or 3, M is an early transition metal, A is mostly group 13 or 14 element and X is C and/or N) has revolutionized the world of nanomaterials, due to the coexistence of both ceramic and metallic nature, giving rise to exceptional mechanical, thermal, electrical, chemical properties and wide range of applications. Although several solid-state bulk synthesis methods have been developed to produce a variety of MAX phases, however, for certain applications, the growth of MAX phases, especially in its high-quality epitaxial thin-films form is of increasing interest. Here, we summarize the progress made thus far in epitaxial growth and property evaluation of MAX phase thin films grown by various deposition techniques. We also address the important future research directions to be made in terms of thin-film growth. Overall, in the future, high-quality single-phase epitaxial thin-film growth and engineering of chemically diverse MAX phases may open up interesting new avenues for next-generation technology.

An exploration of the optoelectronic nature of 4,4-difluoro-8-(C4H3X)-4-bora-3a,4a-diaza-s-indacene (X = O, S, Se) (BODIPY) systems

The optoelectronic properties of heterocyclic BODIPY fluorophores such as 4,4-difluoro-8-(C4H3X)-4-bora-3a,4a-diaza-s-indacene (X = O, S, Se) are explored in the solid-state bulk state. The effects of elements from the chalcogenide family (O, S, and Se) on the density of states, band structure, dielectric functions, extinction coefficient, indices of refraction and reflectance, loss function, and electrical conductivity are investigated. The differences in the rings of 4,4-difluoro-8-(C4H3X)-4-bora-3a,4a-diaza-s-indacene with X = O [2-/3-furyl (Comp1/4)], X = S [2-thienyl (Comp2)], and X = Se [2-selenenyl (Comp3)] are systematically compared. Among the various chalcogens, Comp3 including Se atom was found to be suitable in terms of significantly enhanced dielectric constant, conductivity, refractive index, and extinction coefficient values. The 2-furyl is favorable over the 3-furyl, 2-thienyl, and 2-selenenyl due to the significant contribution of this group to the p-orbitals from 0 to −4 eV. These results reveal that the studied BODIPY derivatives might be proficient multipurpose organic semiconductor materials.

Watt-level ultrafast bulk laser with a graphdiyne saturable absorber mirror.

Few-layered graphdiyne (GDY) was successfully fabricated and applied as a saturable absorber to generate a watt-level ultrafast solid-state bulk laser. The maximum output power of up to 1.27 W was obtained with a pulse width of 23 ps and a repetition rate of 92.9 MHz, using Nd:YVO4 crystal as a gain medium. To the best of our knowledge, this is the first application of GDY as a mode locker in all-solid-state bulk lasers. These results indicate the promising potential of GDY for producing high-power ultrafast lasers.

Few-layer GaSe nanosheet-based broadband saturable absorber for passively Q-switched solid-state bulk lasers.

In this paper, few-layer two-dimensional (2D) GaSe nanosheets were fabricated and utilized as broadband saturable absorbers (SAs) for passively Q-switched (PQS) solid-state bulk lasers operating at 1.06 and 1.99 µm. For 1.06 µm laser operation, the maximum average output power, the shortest pulse width, and the largest single pulse energy were determined to be 438 mW, 285 ns, and 2.31 µJ, respectively, while for 1.99 µm PQS laser operation, they were 937 mW, 383 ns, and 9.56 µJ. Our results identified the great potential applications of few-layer 2D GaSe nanosheets for practical optical modulators such as SAs for pulsed laser generation.

Is Disorder Beneficial in Perovskite-Sensitized Solid-State Upconversion? The Role of DBP Doping in Rubrene

Solid-state bulk lead halide perovskite thin films have recently shown progress as triplet sensitizers in infrared-to-visible photon upconversion (UC) schemes. Common systems pair lead halide perov...

Low-dimensional saturable absorbers for ultrafast photonics in solid-state bulk lasers: status and prospects

Abstract Low-dimensional (LD) materials have originated a range of innovative applications in photonics and optoelectronics owning to their advantages of ultrafast carrier response and distinct nonlinear saturable absorption properties. In particular, these emerging LD materials including zero-, one-, and two-dimensional materials have recently been utilized for short and ultrashort pulse laser generation in the visible, near infrared, and mid-infrared wavelength regions. Here, we review recent progress demonstrating the application of LD materials as versatile, wideband saturable absorbers for Q-switching and mode-locking in all-solid-state lasers. The laser performance in operating wavelength, output power, pulse width, repetition rate, and pulse energy is reviewed. Finally, the challenges and future perspectives are suggested.

Assessment of a solid-state bulk acoustic wave sensor to measure viscosity of Newtonian and Non-Newtonian fluids under static and flow conditions

Monitoring and control of inline viscosity is crucial for process optimisation and for ensuring a high quality final product but currently this parameter is still under-utilised in the dairy industry. This study investigated a solid-state bulk acoustic wave sensor to measure the viscosity of Newtonian (oil standards) and Non-Newtonian fluids (reconstituted skim milk (RSM) at different concentrations) under static (off-line measurements) and flow conditions (in-line measurements). Results illustrated that an increase in total solids (TS) of RSM gave an increase in acoustic viscosity. Non-linear regression was applied to the experimental data to successfully transform the acoustic viscosity outputs into commonly-used reference viscosity values. RSM at higher TS presented a non-Newtonian behaviour and demonstrated shear-thinning properties. Under flow conditions the viscosity of the RSM decreased as a result of shearing experienced in the pipe. This study demonstrated the potential of an acoustic wave sensor to measure in-line viscosity in dairy applications.