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Co-rich ZnCo2O4 (ZCO) two-dimensional (2D) nanosheets are decorated with highly porous, glucose-derived, zero-dimensional (0D) interconnected network-like carbon nanospheres (CNS) using an in situ hydrothermal method. The content of CNS in the reaction is varied to produce two different composites (CNS@ZCO-I and CNS@ZCO-II). Their physicochemical properties are examined and compared with those of the pristine-CNS and ZCO samples. The non-stoichiometry of the elements in ZCO of the composites is quantified by X-ray diffraction using a Reitveld refinement and X-ray photoelectron spectroscopy. CNS@ZCO-II is found to be Co-rich in ZnCo2O4 compared to the other samples. The high surface area of the CNS and non-stoichiometry of Zn/Co in the composites provide a short ion/electron transport path distance, high electronic conductivity, additional electrochemical active sites, and stable structural integrity. This viable strategy offers a good interaction between the CNS and ZCO, which translates to better electrochemical activity as an electrode material for energy storage devices. The CNS@ZCO-II composite with a higher CNS concentration shows an excellent electrochemical performance of approximately 1116.24 F g−1 at 0.35 A g−1 (compared to the pristine-ZCO and CNS@ZCO-I composite).

The introduction of Manganese (Mn) ions (2+ ⇋ 3+ ⇋ 4+) to transition metal oxides proved to be a potential strategy to tailor the redox behavior of these materials for energy storage. We fabricate a lower electronegative element (i.e., Mn) doped copper cobaltite and copper oxide (CuCo2O4/CuO; CCO) heterostructures electrodes through the hydrothermal synthesis route. The ensued electrodes have a more than 2-fold improvement in specific capacity (382.9 C g−1) than the undoped CCO electrode (120.8 C g−1) at 1 A g−1. The all-solid-state asymmetric supercapacitor (ASC) practical device is constructed with higher Mn-doped CCO heterostructures as the positive electrode and activated carbon (AC) as the negative electrode. With a voltage window of 1.5 V, the fabricated ASC device has a high specific energy of 52.6 Wh kg−1 and specific power of 774.3 W kg−1. The long-term cyclic stability of 92% capacity retention after 5000 cycles at the current density of 4 A g−1. Additionally, two ASC devices are series-connected that can power up a red light-emitting diode (LED) display for more than 150 s, demonstrating the device’s efficient power delivery.

A high-temperature solid state reaction route was employed to synthesize the phosphate based new orange-red emitting trivalent samarium (Sm3+) ions doped calcium zinc phosphate (CZP: CaZn2(PO4)2) phosphor. The crystalline phase formation was studied by X-ray diffraction analysis. The surface properties of the phosphor were investigated by X-ray photoelectron spectroscopy. Under the excitation of 402 nm, the emission spectra of CZP:Sm3+ has several peaks and the dominant peak at 596 nm was ascribed to 4G5/2 → 6H7/2 transition. The concentration quenching effect of Sm3+ in CZP phosphor was observed for 5 at%. The mechanism of energy transfer between similar Sm3+ ions was determined to be quadrupole-quadrupole interaction. The decay curves of all phosphors were well fitted to the first-order exponential function. The chromaticity coordinates were located in the orange-red region of the chromaticity diagram. Therefore, these results suggest that the orange-red emitting new CZP:Sm3+ phosphor to be used in the phosphor-converted white light emitting diodes.

The calcium-based lead borate glasses doped with 1 mol% Sm3+ ions were prepared using melt quenching technique. The prepared glass samples were analyzed through an X-ray diffractometer, FT-IR, Optical absorption, Emission, and fluorescence decay analysis. Physical properties have been calculated for the prepared glasses. The absorption spectrum has been recorded for 1.0 mol% Sm3+ ions doped calcium-based lead borate glasses. From the absorption spectrum, oscillatory strengths and JO intensity parameters have been calculated. The visible and near-infrared emission spectra were recorded with 402 nm excitation for 1.0 mol% Sm3+ ions. The prepared glass shows that the highest emission intensity for 4G5/2 → 6H11/2 transition centered at 610 nm. Emission properties for the prepared glass were calculated. Decay profile has been analyzed and lifetime value for 4G5/2 exited level of Sm3+ ion calculated for 1.0 mol% Sm3+ ions doped Ca-based lead borate glass: decay profile was well fitted for exponential decay 2, and the lifetime of 4G5/2 excited level is 1.041 ms. The obtained results suggested that the present 1.0 mol% Sm3+ ions doped calcium-based lead borate glass could be useful for the visible lasers and or photonic display devices applications.

Self-assembled hierarchical rhombus-, spindle-, and peanut-like zinc cobaltite (ZnCo2O4, ZCO) microstructures have strategically engineered using an effective solvothermal approach. The various morphology-regulated ZCO samples have obtained by altering the concentration of precursors in the solvent. Effective strategic methods led to various regulated morphologies, as well as different physicochemical properties, such as the surface area/pore size/volume, crystalline nature, and non-stoichiometry of Zn and Co in the ZCO samples. The metal (Zn/Co)/O deficiencies have quantitatively estimated via X-ray photoelectron spectroscopy and confirmed by the Rietveld refinement of ZCO samples using X-ray diffraction data. A mechanistic study has performed to investigate the formation mechanism of the precursor concentration-dependent self-assembled ZCO microstructures. We demonstrate that the specific capacitance of ZCO has proportional to the Zn-deficiency/Co-excess. The Co-deficient-dependent electrochemical properties have studied for three samples and a decline in the following order: P-ZCO (1608.95 F g−1 at 0.35 A g−1) > S-ZCO (1007.48 F g−1 at 0.35 A g−1) > R-ZCO (629.05 F g−1 at 0.35 A g−1). The simple and inexpensive method of synthesized non-stoichiometric ternary metal oxides micro/nanostructures will introduce new directions in this emerging energy field.

The varied trivalent Samarium ions activated lead borate glass with composition 40B2O3+35PbO+15Ba2CO3+(10-x)Li2CO3+ xSm2O3 (where x = 0.0, 0.1, 0.5, 1.0, 1.1, 1.5, 2.0 mol %) have been prepared by adopting melt-quenching method. For investigated glass matrices physical properties like thickness, density and refractive indices, polaron radius etc. were measured/calculated. The investigated glasses are characterized through the X-ray diffractometer (XRD), Fourier Transform Infra-Red (FT-IR), Absorption, Emission and fluorescence lifetime analysis. The radiative properties for the optimized BPbBaLiSm10 glass have been calculated using J-O spectral intensity parameters. The luminescence spectra consist of four bands at 573, 610, 657 and 718 nm, which were assigned to 4G5/2 → 6H5/2, 6H7/2, 6H9/2 and 6H11/2 transitions of trivalent Sm3+ ions respectively. In the present investigated glasses, BPbBaLiSm10 glass has highest emission peak intensity for the transition 4G5/2 → 6H5/2 at 610 nm. The high values of Stimulated emission cross-section (σemi = 7.56 × 10−22 cm2), gain band width parameter (σemi x τexp = 15.25 × 10−28 cm3) and fluorescence lifetime (τexp = 0.951 ms) for 4G5/2 → 6H5/2 transition of BPbBaLiSm10 glass strongly suggesting that the present investigated BPbBaLiSm10 glass may be potential candidate for development of visible lasers and photonics display (red colour) device applications.