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The tuning of optical, morphological, and structural properties through precise control of the size/thickness of transition-metal chalcogenide is one of the key aspects for practical applications. The present study reports that the microwave-synthesized MnSe1+xTe1–x (MST) nanocomposite by altering Se and Te concentrations is studied for optoelectronic applications. The gradual increase in its crystallinity through MnSe and MnTe2 crystalline phases with an increase in Se/Te ratio is confirmed by the structural study. The existence of different vibrational modes in the sample with alteration in the microstructural region is confirmed by a Raman study. The morphology study shows the nanosheet (nSh) structure as formed for the as-prepared MST samples, confirming the formation of 2D nanomaterial. The nSh thickness gradually decreased with a decrease in the Se concentration and increased Te. The reduction of the optical band gap of nSh is reflected by shifting the absorption edge to a higher wavelength regime. The refractive index values lie between 2.14 and 2.78 for different MST nSh as per theoretical calculation. The presence of various exothermal and endothermal peaks is confirmed by thermal analysis for the present sample. These materials undergo photodetection measurement, where they illustrate commendable responsivity across a range of values: 1.73, 8.88, and 28.88 nA W–1. Additionally, these materials showcase detectivity at levels of 1.14 × 1010, 2.52 × 1010, and 3.96 × 1011 Jones, respectively. The changes in different optical and structural parameters enable the material's applicability in optoelectronic devices. [ABSTRACT FROM AUTHOR]

CuInSe2 and CuInGaSe2 are extremely promising materials for solar cell applications, wherein bandgap shrinkage is highly desirable for manufacturing transparent/semitransparent layers. In this work, this shrinkage was achieved by replacing In with Bi, and the change in current–voltage responses for photodetector applications was further studied. CuBixIn1−xSe2 microrod (MR) flowers (x = 0, 0.2, 0.4, 0.6, and 0.8) were synthesized via microwave synthesis using different Bi/In concentrations. The variation in the composition of Bi/In caused alteration in structural, morphological, and optical behaviors. CuInSe2 showed a polycrystalline nature, while Bi incorporation led to the appearance of a Bi2Se3 phase. Raman peaks corresponding to different vibrational bonds shifted with change in Bi/In content, indicating that the composition variation induced structural transformation inside the matrix. Morphological analysis showed a transition from MRs to MR-based flowers with the introduction of bismuth. Optical absorption was enhanced with an increase in Bi content due to a change in the MR size, forming a flower-like architecture. This reduced the optical bandgap by increasing defects and disorders in the forbidden gap. At 532 nm excitation, broad photoluminescence band emission was observed for all samples. Each spectrum showed three deconvoluted peaks, which were attributed to a transition among localized states over the forbidden gap region. The MRs demonstrated good photo response towards white light. Their photocurrent reduced from the μA to the nA range with varying compositions. The observed optical and electrical properties of the MRs are most suitable for various optoelectronic device applications. [ABSTRACT FROM AUTHOR]

Due to various structural and optical properties, metal chalcogenide nanomaterials are favorable candidates for different optoelectronic applications. In the current report, Cu2Te/NiTe nanocomposites were synthesized via the facile hydrothermal method. With the variation of concentration of Cu and Ni, various materials had been prepared along with pure Cu2Te and NiTe. The observed several vibrational modes in the material through the Raman spectroscopy are well agreed with the appearing phases. The morphological study confirmed the nanostructures are combination of nanoparticles with sheets. The size of nanoparticles varied in the range of 66–34 nm. The absorbance spectra of the nanocomposite exhibit a blueshift and support the enhancement in the optical bandgap. The value of bandgap energy of the composite samples has been noted in the range of 1.8–2.2 eV. This bandgap range enables the material for various optoelectronic applications such as solar cell and other photovoltaic devices. Thermal analysis of the material demonstrates the presences of several endothermic and exothermic peaks. Thus, several studies on the material prevail its various applicability as optoelectronics as well as other thermal application. [ABSTRACT FROM AUTHOR]

In the current paper, we have prepared Cu0.66‐xZn0.34+xSe materials by varying the concentration of copper and zinc (x=0, 0.085, 0.17, 0.255, 0.34) with the help of a facile one‐step hydrothermal method. The X‐ray diffraction study reveals that the as‐prepared nanomaterials show the polycrystalline property. The crystallinity increases with the variation of Zn concentration, and the average crystallite size was calculated in the 39 to 55 nm range. The morphological analysis shows the uniform and agglomerated particles having an average size of around 596 nm. High‐resolution transmission electron microscopy and selected area electron diffraction study reveal the crystalline phases of the prepared sample. The energy‐dispersive X‐ray analysis confirmed the presence of constituent elements in the sample. The sample shows a high optical bandgap in the range of 3.6 eV to 4.09 eV, which was calculated from absorbance spectra. Photoluminescence measurements of the samples were carried out with 532 nm laser excitation, where the defect‐related emission peaks in the 540–850 nm range are observed. A change in the bandgap and optical emission is observed for different compositions. The magnetic properties analysis through the vibrating sample magnetometer reveals that the prepared sample exhibits ferromagnetic behaviour at room temperature, which can be used in magnetic storage applications. The tuning of the optical properties of the samples by varying the copper and zinc concentrations will be useful for various photonic devices. [ABSTRACT FROM AUTHOR]

Recently, dielectric materials with high energy storage capacity, low loss, and good temperature stability are highly desired for the rapidly growing field of power electronics. In the current work, we have investigated the change in electrical, optical, and dielectric properties by varying the concentration of compositional elements Sn and Mn. We have prepared the Sn1–xMnxS (0.1, 0.3, 0.5, 0.7, and 0.9) matrix by using the simple single-step hydrothermal method. The samples show that the reflectance percentage increased with the increase of the Mn amount in the composition. The samples exhibit narrow band gap values, which further increase with the Mn content. The band gap value increases from 0.43 to 0.56 eV. The structural analysis shows that the prepared samples are polycrystalline in nature, having SnS and MnS phases. Furthermore, the crystallite sizes increase with an increase in Mn addition, whereas dislocation density and strain decrease simultaneously. The refractive index is calculated from optical band gap values by using the Dimitrov and Sakka equation. The morphological study reveals the uniformity in size and shape of the prepared composition throughout the sample. The presence of compositional elements Sn, Mn, and S is confirmed by EDX analysis. The electrical study reveals that the sample shows good electrical properties, which increase with the Mn contents. The dielectric behavior as a function of frequency and temperature was investigated, and the parameters like dielectric constant, AC conductivity, impedance spectroscopy, and electric modulus were deeply analyzed. All the above optical, electrical, and dielectric properties of the SnMnS matrix have potential use in the field of electronic and energy storage device applications. [ABSTRACT FROM AUTHOR]

Transition metal chalcogenides have gained significant attention for their optoelectronic and electrical applications in various fields due to their elemental composition-dependent tunable properties. Here, a facile microwave-assisted approach was used to synthesize different CuSe1–xTe1+x-based nanomaterials. By varying the Se and Te concentrations, the morphology of CuSe1–xTe1+x was tuned from nanosheet-based flowers to nanospheres. With the increase in the value of the Te-to-Se content ratio, the material shows the transition from mixed nanosheets/nanospheres to pure nanospheres, where the average sheet thickness and sphere diameter are ∼25 and 80 nm, respectively. The as-synthesized material shows high crystallinity with mixed phases of hexagonal Cu2Te and CuSe. The chemical bonding of the material exhibits shifts of the spectra toward lower binding energies with the decrease in the Se-to-Te ratio. The material exhibits a change in the absorption edge with a blue shift of the optical bandgap for the increase of the Te content. The increment in the absorption makes them eligible for solar cell application. The photoluminescence spectra of different CuSeTe samples show broad emission in the 550–950 nm range with a peak at ∼700 nm. Such optical properties enable CuSeTe materials for possible applications in optoelectronic devices. The dielectric measurement of the sample exhibits an increase in the dielectric constant and loss with temperature, whereas a decrease in both the values is apparent for increase in the frequency. The dielectric study of the material reveals its potential application for energy storage. The photo-response study demonstrated that the material can be employed for photodetector application. [ABSTRACT FROM AUTHOR]

Molybdenum sulfide (MoS2) is one of the most important layered semiconductors. Its importance arises because of its chemical, electrical and optical properties that lead to potential applications in fields such as photocatalysis, electrocatalysis, opto-electronics, etc. Here, we report a simple and novel green hydrothermal synthesis of MoS2 nanoflowers (NFs) from ammonium molybdenum hydrate and thiourea without using any acids or bases. The resultant MoS2 NFs have good crystallinity with a lattice spacing of 0.61 nm. The optical bandgap of the MoS2 NFs was found to be 1.55 eV. Photocatalytic degradation of methylene blue (MB) and crystal violet (CV) dyes with the MoS2 NFs under sun light irradiation was investigated. The MoS2 NFs showed excellent photocatalytic activity towards the degradation of MB and CV with almost 100% degradation with vigorous stirring under natural sun light. This is the fastest degradation of MB and CV dyes ever reported. This is faster than any other reaction performed by a photocatalyst under stirring and this is the first report on high degradation of CV by MoS2 NFs under natural sunlight. In addition to this, the MoS2 NFs displayed excellent repeatability. [ABSTRACT FROM AUTHOR]

We report the indium oxide catalyzed growth of the amorphous SiO nanoropes using the silicon wafer as both source-cum-substrates by thermal evaporation and investigate the luminescence properties. Both blue and yellow emissions are observed from the nanoropes. Blue emission could be attributed to the defect centers of the oxygen deficiency in the nanoropes, whereas yellow emission is due to the trapped excitons in the Si/SiO interface of the materials. Effect of laser exposure on luminescence properties is studied by performing time-dependent PL measurements at different ambiance. Irrespective of laser excitation and ambiance, a monoexponential decay of blue emission with continuous laser exposure is clearly observed, which is due to the gradual removal of surface adsorbed species. [ABSTRACT FROM AUTHOR]