Small Nanocrystallites Research Articles

Using a fast hybrid pixel detector for dose-efficient diffraction imaging beam-sensitive organic molecular thin films

We discuss the benefits and showcase the applications of using a fast, hybrid-pixel detector (HPD) for 4D-STEM experiments and emphasize that in diffraction imaging the structure of molecular nano-crystallites in organic solar cell thin films with a dose-efficient modality 4D-scanning confocal electron diffraction (4D-SCED). With 4D-SCED, spot diffraction patterns form from an interaction area of a few nm while the electron beam rasters over the sample, resulting in high dose effectiveness yet highly demanding on the detector in frame speed, sensitivity, and single-pixel count rate. We compare the datasets acquired with 4D-SCED using a fast HPD with those using state-of-the-art complementary metal-oxide-semiconductor (CMOS) cameras to map the in-plane orientation of π-stacking nano-crystallites of small molecule DRCN5T in a blend of DRCN5T: PC71BM after solvent vapor annealing. The high-speed CMOS camera, using a scintillator optimized for low doses, showed impressive results for electron sensitivity and low noise. However, the limited speed restricted practical experimental conditions and caused unintended damage to small and weak nano-crystallites. The fast HPD, with a speed three orders of magnitude higher, allows a much higher probe current yet a lower total dose on the sample, and more scan points cover a large field of view in less time. A lot more faint diffraction signals that correspond to just a few electron events are detected. The improved performance of direct electron detectors opens more possibilities to enhance the characterization of beam-sensitive materials using 4D-STEM techniques.

PH-induced wurtzite-zinc blende heterogeneous phase formation, optical properties tuning and thermal stability improvement of green synthesized CdS nanoparticles

This is the first paper to report on the pH response to heterogeneous wurtzite/zinc blende phase transformation, optical tunability and thermal stability advancement of the CdS nanoparticles synthesized via co-precipitation, followed by subsequent thermal treatment at a desired annealing temperature of 320 °C, while the solution pH was varied during CdS synthesis by adjusting the ammonium salt concentration. The surface morphology, crystalline structure, functional groups, optical properties and thermal stability of CdS were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR), UV–visible spectrophotometer, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The results show that a dominant sharp band occurs in the FTIR spectra, which authenticates the presence of Cd–S bonds. XRD results reveal that as the pH declines, CdS in the initial cubic phase has gradually transformed into a heterogeneous phase with the coexistence of cubic and hexagonal structures. As observed from the SEM images, the CdS nanoparticles display a homogeneous, smooth and spherically shaped morphology. Optical absorption characterized by UV–visible spectrophotometry denotes that the band gap decreases proportionally with pH, which could be attributed to the formation of larger grain sizes from the aggregation of many small nanocrystallites. TGA and DSC analyses demonstrate an improvement in the thermal stability of CdS with increasing pH values. Consequently, the present findings dictate that pH tunability could be a valuable approach to procuring the desired properties for the respective applications of CdS in diverse fields.

Rapid grain boundary diffusion in foraminifera tests biases paleotemperature records

The oxygen isotopic compositions of fossil foraminifera tests constitute a continuous proxy record of deep-ocean and sea-surface temperatures spanning the last 120 million years. Here, by incubating foraminifera tests in 18O-enriched artificial seawater analogues, we demonstrate that the oxygen isotopic composition of optically translucent, i.e., glassy, fossil foraminifera calcite tests can be measurably altered at low temperatures through rapid oxygen grain-boundary diffusion without any visible ultrastructural changes. Oxygen grain boundary diffusion occurs sufficiently fast in foraminifera tests that, under normal upper oceanic sediment conditions, their grain boundaries will be in oxygen isotopic equilibrium with the surrounding pore fluids on a time scale of <100 years, resulting in a notable but correctable bias of the paleotemperature record. When applied to paleotemperatures from 38,400 foraminifera tests used in paleoclimate reconstructions, grain boundary diffusion can be shown to bias prior paleotemperature estimates by as much as +0.86 to −0.46 °C. The process is general and grain boundary diffusion corrections can be applied to other polycrystalline biocarbonates composed of small nanocrystallites (<100 nm), such as those produced by corals, brachiopods, belemnites, and molluscs, the fossils of which are all highly susceptible to the effects of grain boundary diffusion.

Artificial superstrong silkworm silk surpasses natural spider silks

<h2>Summary</h2> Silks are protein-based biopolymers with unique combinations of different physical properties. Silkworm silk is the most well studied due to its abundance and good mechanical behaviors. However, silkworm silk exhibits a weaker strength than the strongest natural silk, spider dragline silk, which is difficult to be produced on a large scale. Here, a facile strategy is developed for spinning superstrong silk fibers in a metal-ion coagulation bath using regenerated silkworm fibroins. The tensile strength of the artificial silk reaches ∼2.0 GPa, more than 70% higher than the average tenacity of dragline silks. It also exhibits an average Young's modulus of ∼43 GPa, significantly higher than any known natural silks. Structural investigation indicates that the extraordinary strength may be ascribed to high crystallinity and small nano-crystallites formed in the artificial fiber. Incorporation of Zn²⁺ ions into the fiber during spinning and post-spinning drawing processes may also contribute to its excellent mechanical properties.

Controllable Synthesis of Defect-Rich CoMoS Catalysts with Different Morphologies for the Ultradeep Hydrodesulfurization of 4,6-Dimethydibenzothiophene.

CoMoS catalysts with controllable morphology are prepared by a single-source precursor hydrothermal method using sodium diethyldithiocarbamate trihydrate (DDTC) as the ligand and the sulfur source. The effects of the single-source precursor, the pH of the hydrothermal solution, and the surfactant with respect to the morphology, nanostructure, and hydrodesulfurization (HDS) activity of the CoMoS catalyst are investigated. It is revealed that the coordination between the metal atom and DDTC can effectively control the in-plane and out-of-plane crystal growth of MoS2 and promote the formation of the CoMoS active phase. The lower pH value of the hydrothermal solution facilitates the synthesis of CoMoS catalysts with improved purity, lower crystallinity, and smaller nanocrystallites, and the different surfactants would significantly change the morphologies. For HDS activity, the conversion efficiency of 4,6-DMDBT is increased from 71 to 99% by the CoMoS catalysts that have fewer stacking layers of MoS2 slabs. While the high HDS activity is maintained, a notable improvement in selectivity for the direct desulfurization (DDS) pathway is observed for the CoMoS-CTAB catalyst, where the average slab length of MoS2 is the longest.

High-performance CoSbS-based Na-ion battery anodes

CoSbS and its hard carbon-containing nanocomposite (CoSbS@hard-C) are prepared via simple solid-state reactions, and their potential as Na-ion battery (NIB) anode materials is investigated. The electrochemical phase change mechanism of CoSbS during Na insertion/extraction is thoroughly investigated using various ex situ analytical tools. During Na insertion, the CoSbS undergoes a topotactic transformation owing to the formation of a NaxCoSbS (x ≤ 1.6), and then, it is converted into Na3Sb, Na2S, and Co in the fully Na-inserted state via a conversion reaction. Conversely, during Na extraction, Na3Sb transforms to Sb, which alloys with Co to form CoSb. In the fully Na-extracted state, CoSb and S from Na2S are recombined into CoSbS. Owing to the interesting reaction mechanism of CoSbS, the electrochemical performance of the CoSbS and CoSbS@hard-C anodes is excellent. Specifically, when CoSbS is used as a NIB anode, the topotactic transformation between CoSbS and NaxCoSbS (x ≤ 1.6) leads to stable cycling behavior of the NIB and a volumetric capacity of ~480 mAh cm−3 is retained after 100 cycles. Additionally, the NIB with the CoSbS@hard-C anode presents highly reversible and stable capacity (~570 mAh cm−3 after 150 cycles) and fast rate capability (~500 and ~450 mAh cm−3 at 2C and 5C, respectively), which can be attributed to the presence of uniformly dispersed small (5–8 nm) CoSbS nanocrystallites in the hard carbon matrix. Therefore, CoSbS can be utilized as a new anode material for high-performance NIBs.

Electrical conductivity of wood biochar monoliths and its dependence on pyrolysis temperature

Biochar is traditionally used as solid fuel and for soil amendment where its electrical conductivity is largely irrelevant and unexplored. However, electrical conductivity is critical to biochar’s performance in new applications such as supercapacitor energy storage and capacitive deionization of water. In this study, sugar maple and white pine were carbonized via a slow pyrolysis process at 600, 800 and 1000 °C and conductivities of monolithic biochar samples along the radial direction were measured using the 4-probe method. Biochars were characterized using an elemental analyzer, scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The solid carbon in biochar samples was found to consist primarily of disordered carbon atoms with small graphitic nanocrystallites that grow with increasing temperature. The bulk conductivity of biochar was found to increase with pyrolysis temperature—1 to ~ 1000 S/m for maple and 1 to ~ 350 S/m for pine, which was accompanied by an increase in carbon content—91 to 97 wt% and 90 to 96 wt% for maple and pine, respectively. The skeletal conductivity of biochar samples carbonized at 1000 °C is about 3300 S/m and 2300 S/m for maple and pine, respectively (assuming solid carbon is amorphous); both values are above that of amorphous carbon (1250–2000 S/m). This work demonstrated the importance of carbonization and graphitization to electrical conductivity and suggested electron hopping as a likely mechanism for electric conduction in biochar—an amorphous carbon matrix embedded with graphitic nanocrystallites.

Size, porosity, and surface-termination dependence of the radiative and nonradiative relaxation processes of porous silicon

The role of porosity and surface-termination on the radiative and the nonradiative relaxation processes of luminescent porous silicon is investigated using temperature-dependent, time-resolved photoluminescence spectroscopy. We show that, for porous silicon having low- to mid-porosity, radiative relaxation times should be associated with the quantum confinement of excitons (the confined photo-excited electron–hole pairs), while nonradiative relaxation processes are related to the state of the surface (e.g., the surface chemistry), in agreement with previous reports. However, for high-porosity films of porous silicon, we have found much faster low-temperature relaxation times, which are associated with radiative transitions from the triplet excitonic state. This state becomes partially allowed due to a strong coupling and mixing with the singlet state in high-porosity films of porous silicon containing fairly small silicon nanocrystallites.

An aerogel adsorbent with bio-inspired interfacial adhesion between graphene and MoS2 sheets for water treatment

The increasing environmental pollution calls forthe development ofstable functional materials for efficiently binding contaminants, while they can be synthesized and recycled easily. Herein, a three-dimensional (3D) aerogel is constructed by bio-inspired adhesion of graphene and MoS2 sheets with polydopamine (PDA) through a one-step hydrothermal route for the adsorption of the water-soluble organic contaminants. The impact of the bio-inspired interfacial adhesion on the resulting composite aerogel is thoroughly investigated, e.g., the interfacial PDA layer renders the composite aerogel considerably more porous, together with the much higher specific surface area and pore volume, as well as strikingly smaller average pore size and superior stability upon exposure to air, relative to the counterpart without the bio-inspired adhesion. The 3.2 wt% PDA composition is adequate to yield a composite structure with small MoS2 nanocrystallites uniformly dispersed over the modified graphene surface without aggregation. The adsorption of methylene green onto such a 3D composite architecture is spontaneous and endothermic and obeys the Langmuir isotherm model and pseudo-second-order kinetics, with the maximum adsorption capacities over 200 mg/g at all the operating temperatures and the satisfactory recycling properties without significant degradation after 5 cycles.

Sulfur‐Doped Carbon‐Wrapped Heterogeneous Fe3O4/Fe7S8/C Nanoplates as Stable Anode for Lithium‐Ion Batteries

AbstractHigh‐capacity electrode materials have attracted tremendous attention in energy storage systems. However, the large volume expansion always causes breakdown of electrode materials and capacity fading. In this work, we report the preparation of heterogeneous Fe3O4/Fe7S8/C nanoplates with a high lithium diffusion coefficient and excellent lithium storage performance. The heterogeneous nanoplates can be derived from Fe‐MOF octahedra during the sulfidation process. As an anode for lithium‐ion batteries, the Fe3O4/Fe7S8/C composite exhibits higher specific capacity and better rate capability than Fe3O4/C and Fe7S8/C counterparts. The Fe3O4/Fe7S8/C nanoplates deliver a reversible capacity of 859 mA h g−1 after 100 cycles at 0.1 A g−1. Even at 2 A g−1, a capacity of 549 mA h g−1 can still be remained. The good performances are attributed to the small nanocrystallites, high surface area, and the heterogeneous phase boundaries. The strategy can be potentially applied to other metal oxide/metal sulfide composite phases or even bimetallic sulfides and bimetal oxides for high performance lithium‐ion batteries.

Microwave-Assisted Synthesis of Yttrium Iron Garnet Nano Powders for Low Temperature Sintering

Yttrium iron garnet (YIG) nano powders have been successfully synthesized by a chemical co-precipitation plus microwave heating method. The particle sizes of the synthesized YIG powders ranged from 15 nm to 30 nm. Their heating behaviors indicated that small YIG nano crystallites in the synthesized powders started to melt and form liquid phase at a low temperature about 947°C. By using the synthesized powders as the starting materials, the dense YIG ceramics were sintered at the temperature of about 1050–1100°C, which was much lower than the sintering temperature for the powder derived from traditional solid reactions. The liquid phase from melting of small particles promoted the diffusion and re-crystallization, resulting in the low temperature sintering of YIG ceramics.

Nanostructured FeSn2/SnO2-based composites as high-performance anodes for lithium-ion batteries

A nanostructured FeSn2/SnO2 composite was directly synthesized using a simple solid-state ball milling synthesis method by exploiting the disproportionation reaction of SnO and the thermodynamically stable formation of FeSn2. The as-synthesized FeSn2/SnO2 composite comprised small (∼10–20 nm) FeSn2 and SnO2 nanocrystallites, and as a lithium-ion battery anode, it exhibited better electrochemical performance than FeSn2 and SnO2. Furthermore, we prepared a C-decorated FeSn2/SnO2 (FeSn2/SnO2/C) composite. Compared to FeSn2/SnO2, FeSn2/SnO2/C contained smaller nanocrystallites of FeSn2 (∼10 nm) and SnO2 (∼5 nm), which were present in the amorphous C matrix and provided enhanced electrochemical performance. The FeSn2/SnO2/C composite had a high reversible initial capacity of 843 mAh·g−1, a stable capacity retention of above 80% after 100 cycles, and a high C-rate performance of ∼610 mAh·g−1 at 3C rate. Moreover, its electrochemical reaction mechanism during lithium insertion/extraction was determined by ex situ extended X-ray absorption fine structure analysis. Owing to their high electrochemical performance, FeSn2/SnO2/C composites are promising as a new high-performance anode material for lithium-ion batteries.

Monodispersed SnO2 microspheres aggregated by tunable building units as effective photoelectrodes in solar cells

Mesoporous SnO2 microspheres assembled from densely-packed nanocrystalline building units are a class of useful nanomaterials and have extensive optoelectronic applications, but so far it is still a challenge to acquire monodispersed microspheres. Here, monodispersed SnO2 microspheres consisted of aggregated small primary nanocrystallites are synthesized via a surfactant-free solvothermal method. These SnO2 microspheres have high specific surface area, excellent crystallinity and tunable building units. By precisely controlling the nucleation and growth, the obtained microspheres exhibit narrow size distribution, whose diameters are 200 ± 17 and 191 ± 16 nm from pure n-propanol and n-propanol/water mixed solvents, respectively. The sizes of primary nanocrystals slightly increase with the adscititious water. The SnO2 microspheres exhibit large specific surface areas, leading to efficient sensitizer-loading in both dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs). The sub-micron-sized microspheres could also enhance the light-harvesting of the solar cells due to their light-scattering capability. As the primary nanocrystal multiply contacts densely to neighbouring grains, such intergrowth would improve the electron transport through the grain boundaries. Eventually, a power conversion efficiency of 3.83% is yielded for pure SnO2-based DSSCs when the SnO2 microspheres are used as the scattering layers, and an efficiency of 15.41% is obtained when they are used as the electron transport layers in PSCs.

Evaluating nanocrystallite size distributions in doped and undoped nanocrystalline ceramics by X-ray diffractometry

Analytical expressions are formulated that enable the lognormal distribution of nanocrystallite sizes and the mean-squared crystal lattice microstrain in both doped and undoped nanocrystalline ceramics to be routinely determined by X-ray diffractometry. Importantly, these expressions, which are also applicable to most well-annealed nanocrystalline metals/alloys, are developed under the consideration that both the experimental and instrumental X-ray diffraction peaks are modeled by split Voigt functions to account for the (hitherto widely ignored) intrinsic peak asymmetry. The general analytical expressions of this new single-peak line-broadening method are then particularized to the case of small nanocrystallites with uniform composition for which a reasonable simplification (i.e., symmetrization of the experimental peak) can be made without compromising the accuracy of the results. Next, as an example of application the method developed is applied to the characterization of a nanocrystalline ceramic powder, and the nanocrystallite sizes so-determined are validated by transmission electron microscopy. The more complete and reliable microstructural information offered by this single-peak line-broadening method could contribute towards the accurate characterization of both doped and undoped nanocrystalline ceramics, and of most well-annealed nanocrystalline metals/alloys as well, a topic of particular research interest today.

Al-Stabilized Double-Shelled Hollow CaO-Based Microspheres with Superior CO2 Adsorption Performance

Novel, double-shelled hollow Al-stabilized CaO-based microspheres were successfully prepared through a facile, green method using carbonaceous microspheres as sacrificial templates. Both the morphological and adsorption performance differences, between employing organic and inorganic calcium salt as calcium precursors, to fabricate the double-shelled hollow microspheres were exhibited. Derived from calcium acetate, the Al-stabilized double-shelled hollow microspheres with denser shells showed excellent stability. This was ascribed to the shells that were composed of small CaCO3 nanocrystallite (grain size of <50 nm) and homogeneously distributed stabilizer, Al2O3. Well-spherical, porous hollow structures facilitated CO2 diffusion and buffered mechanical stresses generated by volume change during the calcium looping. The sorbent, CaA40Al1, exhibited a favorable high-temperature CO2 adsorption performance with the capacity of 0.40 g of CO2/g of ads over 60 carbonation/calcination cycles.

Binding Nanosized Cobalt Chalcogenides in B,N‐Codoped Graphene for Enhanced Sodium Storage

AbstractA general process is developed to prepare binding nanosized cobalt chalcogenides in B,N‐codoped graphene (CoSe2/BNG and CoS2/BNG). When used as anodes for sodium‐ion batteries, the CoSe2/BNG and CoS2/BNG deliver excellent sodium‐storage performance. The CoSe2/BNG displays a reversible capacity of 270 mAh g−1 after 2000 cycles at a current density of 1 A g−1. Even at 20 A g−1, it can still give a capacity of 187 mAh g−1. Moreover, the CoS2/BNG shows 387 mAh g−1 at 10 A g−1, demonstrating its superior high rate performance. The enhanced sodium‐storage properties of the CoSe2/BNG and CoS2/BNG nanocomposites may be attributed to the high conductive graphene network, enhanced sodium storage of B,N‐codoping in graphene, and the small CoSe2 and CoS2 nanocrystallites that shorten the electronic and ionic diffusion length throughout the electrode.

Synthesis of copper-cobalt hybrid oxide microflowers as electrode material for supercapacitors

Copper-cobalt hybrid oxide (CuCoO-H) microflowers were prepared by a cost-effective and facile two-step growth-annealing approach toward supercapacitor electrode materials. The unique architecture obtained by adjusting the calcination atmosphere, ultrathin nanosheets with small nanocrystallites providing high specific surface area and appropriate mesoporous structure enhancing electrolyte penetration, as well as synergistic effect among CuCo2O4, Cu2O and CoO makes the CuCoO-H display excellent electrochemical performances, showing the advantages of novel hybrid strategy, which shed new light on searching cheap and efficient electrode materials for supercapacitors. The CuCoO-H electrodes showed outstanding electrochemical stability, after 10,000 cycles of measurements at a current density of 3 A g−1, retaining 99.4% of the initial specific capacitances and impressive high-rate capability (405.36 F g−1 at 20 A g−1). Furthermore, the CuCoO-H as the positive electrode and active carbon as the negative electrode constitute an asymmetric supercapacitor, exhibiting a high energy density of 32.2 W h kg−1 at the power density of 644 W kg−1. At last, two asymmetric supercapacitors were assembled in series to light a red commercial light-emitting diodes (LEDs) for the practical application.

Hierarchical ZSM-5 zeolite synthesized via dry gel conversion-steam assisted crystallization process and its application in aromatization of methanol

Hierarchical ZSM-5 zeolites were prepared by “Dry Gel Conversion-Steam Assisted Crystallization” (DGC-SAC) procedure without the involvement of additional template. Moreover, the formation mechanism and feather of mesopores were summarized. Nanoscale Kirkendall effect was existed in the growth of zeolite crystals under high SiO2/TPA+ ratio, which was responsible for the production of intra-crystal mesopores. However, small ZSM-5 nano-crystallites, with the average diameter of <50 nm, were successfully synthesized under low SiO2/TPA+ ratio. The random assembly of these nano-crystallites gave rise to abundant inter-crystal mesopores within these nano-crystallites zeolites. Benefiting from the significantly higher concentration of TPA+ at the surface of amorphous aluminosilicate during the DGC-SAC process, the DGC-SAC procedure exhibited higher usage efficiency of template (TPA+) than that of conventional “Hydrothermal Crystallization” (HC) route, and the ZSM-5 zeolites with a low consumption of TPA+ (SiO2/TPA+ = 53.7) could be successfully synthesized by DGC-SAC method. Compared with the conventional ZSM-5 zeolites prepared by HC routes, the hierarchical ZSM-5 zeolites prepared by DGC-SAC procedure exhibited significantly higher catalytic lifetime and selectivity of light aromatics (benzene (B), toluene (T) and xylene (X)) in aromatization of methanol under same low addition of TPA+ (SiO2/TPA+ = 13.5). Moreover, the produced hierarchical ZSM-5 zeolites (SiO2/TPA+ = 13.5) also exhibited superior catalyst stability after being further hydrothermally treated at 160 °C for 72 h. TG analysis of all used catalysts confirmed that the produced hierarchical ZSM-5 zeolites had higher coke capability and lower average rate of coke formation.

Polarization-selective Excitation of Dye Luminescence on a Gold Film by Structured Ultrashort Laser Pulses

Donut-shaped visible (515 nm) femtosecond laser pulses with linear, radial and azimuthal polarizations after tight focusing (numerical aperture NA = 0.65) have been used for spectrally adjusted excitation of plasmonenhanced rhodamine 6G dye luminescence on the surface of a nanocrystalline 45-nm thick gold film with its plasmon resonance near the laser line. Significant luminescence output increments—1.7-fold for radial polarization compared to the azimuthal one, and almost 3-fold—compared to the linear one, have been observed. This effect is related to significant transformation of the transverse electrical field component into longitudinal one for radial polarization (up to 33% in intensity, according to our calculations), and corresponding increase in excitation efficiency of plasmons in the smaller nanocrystallites throughout the film.

Effect of Tellurium Concentration of the Solution on the Structural, Optical and Luminescence Properties of Cadmium Telluride Nanoparticles

Water-soluble cadmium telluride (CdTe) nanoparticles (NPs) were prepared using L-cystine as a capping agent. The reaction was carried out under basic conditions (at pH=11) and refluxed at 100oC for 1 h. In this work, different tellurium (Te) concentrations in the solution of L-cystine functionalized CdTe NPs were prepared at low temperature of 100oC and discussion of its effect was done in detail. The CdTe NPs were analyzed using X-ray diffraction (XRD), ultraviolet-vis and photoluminescence (PL) spectroscopy. Structural parameters estimated by XRD revealed cubic phase of CdTe at lower Te concentrations and hexagonal phase of Te emerging at higher Te concentration. XRD results showed that the NPs consisted of small CdTe nanocrystallites, 3.1-4.5 nm in size. Scanning electron microscopy was used to analyze the surface morphology of the samples and was found that it varied with different Te concentration in the aqueous solution. They consisted of spherical, rod-like and blade-like type of morphologies. The absorption thresholds of the CdTe NPs were red shifted when Te concentration was increased, due to the quantum confinement effects displayed by nanocrystalline CdTe NPs. Optical band gap energy estimated showed a decrease with an increase in the amounts of Te present while the band emissions observed in the PL spectra of CdTe NPs red shifted from 536-559 nm upon an increase in Te ratio. The PL full width at half maximum increased from 49-60 nm with increase in Cd:Te from 1:0.1 to 1:1 displaying narrow size distribution of the NPs. Highest PL intensity was realized for a 1:0.4 Cd:Te molar ratio which is an indication of improved crystallinity.