Glassy Matrix Research Articles

High‐Entropy Alloy‐Induced Metallic Glass Transformation: Challenges Posed by in situ Alloying via Additive Manufacturing

In situ alloying and fabricating glassy structures through a layer‐by‐layer fashion approach are challenging but have high potential to develop novel‐graded materials. For the first time, this cost‐effective approach is applied to additive manufacturing (AM) of a Zr‐based bulk metallic glass (BMG) from high‐entropy alloys (HEAs). A newly developed composition of Zr40Al20Cu20Ti20 is fabricated through laser powder bed fusion (LPBF). Process parameters are optimized within a wide range of laser power (50–200 W) as well as scanning speed (50–800 mm s−1). In all printed samples, microscopic and compositional examinations reveal no glass formation, but very fine grains and CuTi and AlTi nanocrystals. Some glassy transitions at the interfaces may be encouraged to occur with proper melting and mixing. However, the main reason for not obtaining a glassy matrix is the substantial proportion of unmelted Zr raw powder throughout the structure as spherical particles. Consequently, glass formation can be hindered by a considerable amount of compositional deviation. During LPBF, in situ alloying poses significant challenges to developing BMGs. Hence, the various stages of the process, including raw material specifications, laser settings, and process parameters, should be investigated further.

Mineralogical Properties of the Copper Slags from the SarCheshmeh Smelter Plant, Iran, in View of Value Recovery

Annually, hundreds of thousands of tons of slags are involved in the reverberator and flash smelting as well as converting operations of Cu-Fe sulfide concentrates to produce matte in the Sar Cheshmeh copper smelter plant, Iran, disposed in the landfill and cooled in air. Due to their relatively high average copper content (about 1.5 wt%), a mineral processing plant based on the flotation process has recently been established to produce thousands of tons of Cu-sulfide concentrate after slag crushing and fine grinding operation. In order to make the flotation process more efficient, more knowledge is required on the form and origin of the copper losses in the slag. To achieve this, mineralogical studies of the slags using optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) methods have been carried out. Mineralogical analyses showed the main part of copper losses into the semi- to fully-crystallized magnetite-rich reverberator and flash slags characterized by crystal–glass matrix ratio ≤ 1 is moderate to coarse particles of Cu-Fe sulfides, i.e., chalcopyrite (CuFeS2) and bornite (Cu5FeS4), that are mainly chemically entrapped. In contrast, the mechanically entrapped fine- to coarse-grain (from 20 up to 200 µm) spherical-shaped of high-grade matte particles with chalcocite (Cu2S) composition containing droplets or veinlets of metallic copper (Cu0) are the dominant forms of copper losses into the converter slags characterized by crystal–glass matrix ratio > 1. From the value recovery point of view, our result show that the fully crystallized slags containing moderate- to coarse-grain copper-bearing particles will result in efficient recovery of a significant amount of entrained copper due to better milling response compared to semi-crystallized ones due to locking the fine- to moderate-grain copper particles in the silicate glassy matrix. Laboratory-scale grinding experiments showed that normal (≤74 μm) to fine (≤44 μm) grinding of high- Cu grade slags lead to a significant increase in the liberation degree of copper particles. in contrast, the increase in fine particle fractions (<37 μm) due to re-grinding or ultra-fine grinding of the originally low-Cu grade slags does not lead to the liberation of copper particles, but it will reduce the efficiency of the flotation process. This study suggests that the highest rate of copper recovery of the slag by the flotation process will be obtained at particle size 80% passing 44 µm which has also reached the optimal liberation degree of copper-bearing particles.

Ultrasonic-assisted fabrication of metallic glass composites

Metallic glass composites (MGCs) inherit the high strength of their glassy matrix and exhibit remarkable plastic deformation, hence have great potential in engineering applications. However, their preparation often relays on arduous component exploration or involves elusive technological process. Here, we report a facile route to fabricate MGC using ultrasonic vibration (UV) and the fabrication process can be manually controlled. By appropriately modulating the amplitude and time of UV, the MGCs with different proportion of crystalline phase can be obtained readily and accurately in seconds under low-pressure at room temperature owing to the unique soften behavior of MG under UV. The deformation behavior and the hardness were evaluated using nanoindentation testing, demonstrating better ductility when compared with the as-cast sample and reduced hardness for the MGCs as increased proportion of crystalline phase. These results may provide a new approach for the rapid and controllable fabrication of MGCs with designed properties.

Effect of Ag2S on electrical conductivity and dielectric relaxation in Ag2O-MoO3-P2O5 ionic glassy systems

The influence of Ag2S incorporation on the electrical and dielectric properties of the host Ag2O-MoO3-P2O5 glassy matrix has been systematically studied in the present communication. By applying the well-known Archimedes principle, the density of the samples has been determined. The ionic property for all the as-prepared glassy systems has been explored methodically. The nearly identical obtained values of the crossover frequency and the activation energy for DC and AC conductivity suggest that the same mechanism is responsible for electrical conduction. For the purpose of inspecting the frequency and temperature dependent AC conductivity, the Almond-West formalism model has been used. The observed values of dielectric constant and dielectric loss are found to increase with the temperature rise and drop with rising frequency. The coinciding scaled complex electric modulus spectra suggest a non-Debye type dynamical relaxation mechanism, which also indicates that the relaxation mechanism is temperature independent but composition dependent.

Improved Plasticity of Fe25Co25Ni25(Si0.3B0.7)25 High Entropy Bulk Metallic Glass through the Addition of Cu

This work was focused on enhancement in the plasticity of Fe25Co25Ni25(Si0.3B0.7)25 high entropy bulk metallic glass (HE-BMG) by adding minor Cu (0–1.2, in at.%). It is found that the appropriate addition of Cu can efficiently improve the plasticity of the present HE-BMG while the excessive addition of Cu will deteriorate again the plasticity, and especially, the plastic strain of the present HE-BMG is improved from 0.8% for the Cu-free alloy to 4.7% for the 0.3 at.% Cu-added alloy. The transmission electron microscopy observation shows that there are many α-Fe (Co, Ni) clusters with sizes of less than 5 nm dispersed in the glassy matrix in the 0.3 and 0.6 at.% Cu-added alloys, which may account for the significant improvement in the plasticity of the two alloys, and further increase in Cu content more than 0.9 at.% leads to the precipitation of α-Fe (Co, Ni) and Fe (Co, Ni) B compound grains with diameters of tens of nanometers, in which the plasticity of the present HE-BMGs has deteriorated rapidly.

Laser additive manufacturing of Zr-based bulk metallic glass composite improved by TRIP effect

Laser additive manufacturing (LAM), as a fascinating technique, is equipped with the potential to fabricate bulk metallic glasses (BMGs) with arbitrary geometries. However, the serious thermal stress induced by the LAM process always causes the harmful cracks to be left inside the Zr-based BMGs with brittleness characteristics, which will lead to a sharp deterioration in fracture toughness. To solve this dilemma, B2 phase with excellent plasticity, realizing work-hardening through martensitic transformation, was precipitated during the cooling process of Zr 48 Cu 46.5 Al 4 Nb 1.5 BMG composite (BMGC). The deposited Zr-based BMGCs possess composite structures, i.e ., B2 phase is distributed in the partially crystallized glassy matrix. The TRIP effect provided by B2 phase can not only inhibit the generation of cracks, but also effectively avoid premature shearing-off through the sample to greatly improve the fracture strength.

Study of the growth mechanism of ε-Fe2O3 crystals in Chinese sauce glaze replications

The ferric oxide ε-Fe2O3 has recently been at the center of interest of scientists to understand its physical properties and find efficient methods of synthesis. In parallel to those studies, ε-Fe2O3 was discovered in several ancient brown and black glazed ware produced in different Chinese kilns and time periods. The ubiquity of such phase in ancient glaze in spite of its low stability could be a very interesting indicator to understand both the traditional manufacturing of ancient Chinese glaze and the growth of ε-Fe2O3 in a glassy matrix. This study is based on a set of glazed samples taken out from the kiln at different stages of the firing. Analyses show that ε-Fe2O3 crystals begin to grow at high-temperature at the beginning of the cooling stage. The growth continues through iron ion pumping from the glaze. The iron depletion of the glaze causes the dissolution of iron rich particles, which were formed during the heating and ion diffusion from deeper in the glaze. Al-substitution in ε-Fe2O3 was observed, with a higher Al concentration in more developed crystals. Ti- and Mg-substitutions were also highlighted. A set of equation is proposed to model the formation process.

Thermoelectric performance of Ni, Co, and Fe nanoparticles incorporated into their metal borates glassy matrices

AbstractHere, we present our current attempt to intrinsically dope Ni0, Co0, and Fe0 nanoparticles within NiII‐, CoII‐, and FeII‐borate glassy matrices, respectively. The system was prepared by one‐pot reaction of the desired MTII salt with excess NaBH4 through an in‐situ reduction and hydrolysis processes to afford metallic MT0 nanoparticles dispersed into the MT‐BO3 matrix. The composition and structural characteristics of these MT0:MT‐BO3 materials were identified by thermal oxidation, ATR‐IR, X‐ray powder diffraction, and magnetic techniques as glassy/amorphous borate matrices containing magnetic nanoparticles. The electrical conductivity (σ) of cold‐pressed discs of these metal‐doped composites shows that they behave as nonohmic semiconductors within the temperature range of 303 ≤ T ≤ 373 K suggesting a mixed electronic‐ionic conduction. However, their thermal conductivity (κ) occurs through phonon lattice vibration dynamics rather than electronic. The σ/κ ratio shows a steep non‐linear increase from 9.4 to 270 KV−2 in Ni0:Ni‐BO3. In contrast, a moderate‐weak increase is observed for Co0:Co‐BO3 and Fe0:Fe‐BO3 analogs. The obtained materials are examined for thermoelectric (TE) applications by determining their Seebeck coefficient (S) power factor (PF), figure of merit (ZT), and conversion efficiency (η%). All the TE data shows that Ni0:Ni‐BO3 (S, 80 μVK−1; PF, 97.7 mWm−1 K−1; ZT 0.54; η, 2.15%) is a better TE semiconductor than the other two MT0:MT‐BO3. This finding shows that Ni0:Ni‐BO3 is a promising candidate to exploit low‐temperature waste heat from body heat, sunshine, and small domestic devices for small‐scale TE applications.

Crystallization and polymorphic behaviour of melt miscible blends of crystalline homopolymers with close melting temperatures under confinement

The confined crystallization behavior of the crystalline/crystalline blends of poly(ethylene oxide) (PEO) and poly(butylene adipate) (PBA) in the electrospun nanofibers fabricated from the ternary blends of polystyrene (PS), PEO, and PBA, where PS was present as the majority component, was investigated. The electrospun nanofibers had PS as the matrix whereas the PEO/PBA mixed phase, with total weight fraction of 0.2 or less, constituted the dispersed domains having sizes of the order of only few hundred nanometers. Hence, the crystallization induced phase separation of PEO and PBA occurred within the confined domains. Despite extremely close melting temperature of PEO and PBA, faster crystallization kinetics of PEO led to entrapment of PBA in the intraspherultic regions of the former. Hence, further crystallization of PBA occurred under hierarchical confinement where the larger and smaller length-scale confinements were imposed by the glassy PS matrix and PEO crystals, respectively. Such a scenario resulted in crystallization occurring both via homogenous as well as heterogeneous crystallization mechanism. Interestingly, the homogenous nucleation of PEO was suppressed whereas the heterogeneous nucleation was enhanced in the ternary blend nanofibers even at very low weight fraction. Most significantly, it was observed, that during melt-recrystallization, memory of chain orientation is retained which favoured the formation of α-crystals in PBA. The present study highlights the role of confinement as well as chain orientation, on the crystallization behaviour, in crystalline/crystalline blend systems for which limited studies have been done so far.

Rhenium(I) Complexes with Neutral Monodentate Coligands and Monoanionic 2-(1,2,4-Triazol-5-yl)pyridine-Based Chelators as Bidentate Luminophores with Tunable Color and Photosensitized Generation of 1O2: An Integrated Case Study Involving Photophysics and Theory.

In this work, we describe the synthesis as well as structural, photophysical, and theoretical investigation of a new coordination chemical concept involving rhenium(I) complexes bearing monoanionic 1,2,4-triazolylpyridine-based bidentate chromophores. The X-ray diffractometric analysis of single crystals revealed particular packing features: the trifluoromethylated exemplar displayed two kinds of arrangements of the coordination centers, where the bidentate ligands at the edges of the unit cell are staggered parallel to each other, whereas those inside show antiparallel stacking with respect to the external ligands. On the other hand, the complexes bearing an adamantyl substituent yield a linear arrangement, where the bulky moiety of one luminophore points to the pyridine center of the adjacent ligand of the neighboring complex while including methanol molecules hydrogen-bonded to the triazolato unit. We observed that the photophysical properties of the complexes (photoexcited-state lifetimes, photoluminescence maxima and quantum yields) can be adjusted by tuning of the substitution pattern at the bidentate luminophore as well as by variation of the monodentate coligand. The photoluminescence spectra and photoexcited-state lifetimes of the crystalline phases were measured by phosphorescence lifetime micro(spectro)scopy. Interestingly, the vibrationally resolved emission spectra of the crystals closely resemble those of diluted frozen glassy matrixes at 77 K, in contrast with the broad bands observed in amorphous solids and in fluid solutions, where the charge-transfer character is enhanced. While the photoluminescence quantum yields (ΦL) reach up to 15%, the complexes are able to attain up to 55% efficiency regarding the photosensitization of 1O2 (ΦΔ), depending on the combination of luminophore and coligand. Theoretical calculations showed that the photoexcited triplet (T1) state has a metal-ligand-to-ligand charge-transfer character, where promotion to the excited electronic configuration shortens the Re(I)-N bond involving the bidentate triazolylpyridine while stretching the three fac-CO-Re(I) bonds as well as the linkage to the axial monodentate coligand. The calculated vertical (Evl) and 0-0 (E(0-0)) radiative transition energies are in very good agreement with the experimental values (Eexplum).

Study of sauce glazed wares from Yaozhou kilns (Northern Song Dynasty, 960–1127 CE): Probing the morphology and structure of crystals in the glazes

Sauce glaze is one of the main varieties of glazes produced in the Yaozhou kilns during the Song Dynasty. It is famous for its reddish-brown color and high gloss. In this work, the elemental composition, morphology, structure, and light reflectivity of glazes of archeological sherds were systematically studied. A large number of ε-Fe2O3 dendritic crystals were observed in the glazes. Alkali etching was implemented to remove the glassy matrix surrounding these crystals to further investigate their microstructure. SEM observations emphasize that they are composed of well-arranged parallel branches separated by about 230 nm, each of which consisting of offset stacks of many small flake-shaped crystals, with the offset ranging from 100 to 110 nm. Based on these results, the origin of the reddish-brown color and high gloss was discussed. In addition, cordierite crystals were observed for the first time in the sauce glaze from Yaozhou kilns.

Metallic Mimosa pudica: A 3D biomimetic buckling structure made of metallic glasses.

Metallic Mimosa pudica, a three-dimensional (3D) biomimetic structure made of metallic glass, is formed via laser patterning: Blooming, closing, and reversing of the metallic M. pudica can be controlled by an applied magnetic field or by manual reshaping. An array of laser-crystallized lines is written in a metallic glass ribbon. Changes in density and/or elastic modulus due to laser patterning result in an appropriate size mismatch between the shrunken crystalline regions and the glassy matrix. The residual stress and elastic distortion energy make the composite material to buckle within the elastic limit and to obey the minimum elastic energy criterion. This work not only provides a programming route for constructing buckling structures of metallic glasses but also provides clues for the study of materials with automatic functions desired in robotics, electronic devices, and, especially, medical devices in the field of medicine, such as vessel scaffolds and vascular filters, which require contactless expansion and contraction functions.

Superionic Bifunctional Polymer Electrolytes for Solid-State Energy Storage and Conversion.

Achieving superionic conductivity from solid-state polymer electrolytes is an important task in the development of future energy storage and conversion technologies. Herein, a platform for innovative electrolyte technologies based on a bifunctional polymer, poly(3-hydroxy-4-sulfonated styrene) (PS-3H4S), is presented. By incorporating OH and SO3 H functional groups at adjacent positions in the styrene repeating unit, "intra-monomer" hydrogen bonds are formed to effectively weaken the electrostatic interactions of the SO3 - moieties in the polymer matrix with embedded ions, promoting rich structural and dynamic heterogeneity in the PS-3H4S electrolyte. Upon the incorporation of an ionic liquid, interconnected rod-like ion channels, which allow the decoupling of ion relaxation from polymer relaxation, are formed in the stiff motif of the polymeric domains passivated by interfacial ionic layers. This results in accelerated proton hopping through the glassy polymer matrix, and proton hopping becomes more pronounced at cryogenic temperatures down to -35 °C. The PS-3H4S/ionic liquid composite electrolytes exhibit a high ionic conductivity of 10-3 S cm-1 and high storage modulus of ≈100MPa at 25 °C, and can be successfully applied in soft actuators and lithium-metal batteries.

Ultralarge-scale anomalous phase separation discovered in a Cr-Fe-Co-Ni-Zr high-entropy metallic glass system

Anomalous phase separation in metallic glasses is a longstanding issue that has been controversial since it was first implied in 1969 due to the influence of microstructure artifacts and the lack of direct large-scale (over nanoscale) evidence. This study confirms an ultralarge scale anomalous glass phase separation phenomenon in a Cr-Fe-Co-Ni-Zr high-entropy metallic glass in which any pair of atomic components has a nonpositive heat of mixing using interferencefree visible-light, atomic force, scanning electron, and double spherical aberration-corrected atomic resolution analytical electron microscopes. The second glassy phase separated from the glassy matrix has an ultralarge size of tens of micrometers, which can be controlled by the cooling rate during sample preparation. A mechanism of before-monotectic-like liquid immiscibility is introduced to interpret the phenomenon, which helps understand the anomalous phase separation in metallic glasses and in other fields, such as liquid-liquid phase separation in cells.

Glass-Ceramics from Trachyte Rock- Limestone or Magnesite

Inexpensive sintered glass-ceramic glaze was prepared from a mixture of Egyptian trachyte with either limestone or magnesite. A represented trachyte rock was pulverized to powder (<0.083 mm) and also both limestone and magnesite. The well mixed batches were melted near 1450 °C/3 h temperature then the glass melt was quenched in water, dried, pulverized to powder and finally shaped in moulds. The sintering process of the pre-shaped glasses, within 1000-1100 °C range, gave augite and olivine in case of trachyte-magnesite whereas wollastonite and Ca-olivine in case of trachyte-limestone. However, cristobalite was developed in both cases. The microstructures in both cases showed glassy matrix scattered with submicron and nano-size crystals either in irregular shape in case of trachyte-limestone or clear crystals in case of trachyte-magnesite. The densities of the sintered samples were in the range of 2.36 and 2.57 g/cm3 in case of the trachyte-limestone and 2.36 and 2.64 g/cm3 in case of the trachyte-magnesite. The coefficient of thermal expansion (CTE) and the hardness of the sintered glass-ceramic were in the range of 6.2-8.5 × 10−6 °C−1 and 440-563 GPa respectively. However, the CTE values decreased in case of trachyte-limestone whereas the hardness values were high in case of trachyte-magnesite. The present glass-ceramic samples had porcelain nature and could be used in cladding of wall and floor.

Atomic-scale icosahedral short-range ordering in a rejuvenated Zr-based bulk metallic glass upon deep cryogenic treatment

Tailoring the formation and distribution of loose-packing regions and dense-packing regions in the bulk metallic glasses (BMGs) has long been considered to facilitate macroscopic mechanical properties and break strength-ductility trade-off. Herein, studies on structural heterogeneity caused by the deep cryogenic treatment (DCT) were systematically carried out to not only probe the atomic-scale structure-property relationships but also further understand the deformation mechanisms involving improved plasticity without sacrificing strength on the basis of these experimental results in rejuvenated Zr-based BMGs. The internal stress due to the cooling contraction will activate the atomic motion in weakly bonded regions and meanwhile form perfect icosahedral short-range ordering (ISRO) via containing mobile atoms to become denser geometric configurations. The multiplication and propagation of shear bands are closely associated with their structural features originating from the optimization of perfect icosahedral ordered structures in the rejuvenated glassy matrix. It is believed that these findings are helpful to shed light on the correlations between atomic-scale structural heterogeneity and macroscopic mechanical properties and further provide new possibilities for the development of promising BMGs with strength-ductility synergy.

Mechanical behavior and deformation mechanism of shape memory bulk metallic glass composites synthesized by powder metallurgy

• Powder metallurgy synthesis of bulk metallic glass composites with TRIP effect. • Quantification of confining effect of glassy phase on martensitic transformation. • Quantification of each phase to the plasticity of bulk metallic glass composites. • Mechanism for shear band initiation in shape memory bulk metallic glass composites. The synthesis of martensitic or shape-memory bulk metallic glass composites (BMGCs) via solidification of the glass-forming melts requires the meticulous selection of the chemical composition and the proper choice of the processing parameters in order to ensure that the glassy matrix coexists with the desired amount of austenitic phase. Unfortunately, a relatively limited number of such systems, where austenite and glassy matrix coexist over a wide range of compositions, is available. Here, we study the effectiveness of powder metallurgy as an alternative to solidification for the synthesis of shape memory BMGCs. Zr 48 Cu 36 Al 8 Ag 8 matrix composites with different volume fractions of Ni 50.6 Ti 49.4 are fabricated using hot pressing and their microstructure, mechanical properties and deformation mechanism are investigated employing experiments and simulations. The results demonstrate that shape-memory BMGCs with tunable microstructures and properties can be synthesized by hot pressing. The phase stability of the glass and austenitic components across a wide range of compositions allows us to examine fundamental aspects in the field of shape memory BMGCs, including the effect of the confining stress on the martensitic transformation exerted by the glassy matrix, the contribution of each phase to the plasticity and the mechanism responsible for shear band formation. The present method gives a virtually infinite choice among the possible combinations of glassy matrices and shape memory phases, expanding the range of accessible shape memory BMGCs to systems where the glassy and austenitic phases do not form simultaneously using the solidification route.

Plasmon Mediated Electron Transfer and Temperature Dependent Electron-Phonon Scattering in Gold Nanoparticles Embedded in Dielectric Films.

Excitation of localized surface plasmon resonance in metal nanoparticles (NPs) embedded in a glassy matrix generates hot electrons, which can be extracted for different optoelectronic applications. The insights of plasmon relaxation dynamics with varying surrounding dielectric environments and temperature dependence electron-phonon scattering process in gold (Au) NPs are still not very clear. Here, we have employed ultrafast transient absorption (TA) spectroscopy to explore the hot plasmon mediated electron transfer (PMET) and electron-phonon dynamics of photo-excited Au NPs in glassy film matrix with variable SiO2 /TiO2 compositions at cryogenic (5 K) to room temperature (300 K). Herein, we have chosen two pump excitation wavelengths (400 and 700 nm). The 400 nm excitation (d→sp) generates hot electron and the 700 nm excitation (sp→sp) provide information of direct plasmon relaxation. Drastic reduction of the transient signal of Au NPs in the high TiO2 content film as compared to pure SiO2 confirm hot electron transfer (HET) from Au plasmon to TiO2 . Electron-phonon scattering time constant (τe-ph ) of Au NPs in the glassy film is found to be faster in presence of TiO2 due to facile electron transfer/injection. Temperature dependent TA studies suggest that electron-phonon scattering time decreases with temperature. These findings would assist to develop more advanced photo-voltaic, opto-electronic and quantum optic-based devices using the plasmonic metal NPs.

Mechanism of Electron Spin Decoherence in a Partially Deuterated Glassy Matrix.

Long electron spin coherence lifetimes are essential for applications in quantum information science and electron paramagnetic resonance, for instance, for nanoscale distance measurements in biomolecular systems using double electron-electron resonance. We experimentally investigate the decoherence dynamics under the Hahn echo sequence of the organic radical d18-TEMPO in a variably deuterated frozen water:glycerol matrix. The coherence time (phase memory time) TM scales with proton concentration as [1H]-0.65. For selectively deuterated matrices, decoherence is accelerated in the presence of proton clustering, that is, substantial short-range density in the proton-proton radial distribution functions (<3 Å). Simulations using molecular dynamics and many-body spin quantum dynamics show excellent agreement with experiment and show that geminal proton pairs such as CH2 and OH2 groups are major decoherence drivers. This provides a predictive tool for designing molecular systems with long electron spin coherence times.

Monoanionic C^N^N Luminophores and Monodentate C-Donor Co-Ligands for Phosphorescent Pt(II) Complexes: A Case Study Involving Their Photophysics and Cytotoxicity

A family of Pt(II) complexes bearing monoanionic C^N^N ligands as luminophoric units as well as a set of monodentate ligands derived from allenylidene and carbene species were synthesized and characterized in terms of structure and photophysical properties. In addition, we present the extraordinary molecular structure of a phosphorescent complex carrying an allenylidene ligand. Depending on the co-ligand, an effect can be observed in the photoluminescence lifetimes and quantum yields as well as in the radiative and radiation less deactivation rate constants. Their correlation with the substitution pattern was analyzed by comparing the photoluminescence in fluid solution at room temperature and in frozen glassy matrices at 77 K. Moreover, in order to gain a deeper understanding of the electronic states responsible for the optical properties, density functional theory calculations were performed. Finally, the cytotoxicity of the complexes was evaluated in vitro, showing that the cationic complexes exhibit strong effects at low micromolar concentrations. The calculated half-maximum effective concentrations (EC50 values) were 4 times lower in comparison to the established antitumor agent oxaliplatin. In contrast, the neutral species are less toxic, rendering them as potential bioimaging agents.