PUBLICATIONS

Journals

  • 134

    Rare-earth-free Mn4+ions activated Ba2YSbO6 phosphors for solid-state lighting, flexible display, and anti-counterfeiting applications

    Abstract

    Recenlty, rare-earth (RE)-free ions (Mn4+) activated phosphor materials are becoming an alternative source while replacing Eu2+ ions activated metal oxide, phosphate, and nitride phosphors for multi-functional applications. In this report, we prepared novel RE-free Mn4+ (mol%) ions activated double perovskite-type Ba2YSbO6 (BYSO:Mn4+) phosphor materials by a solid-state reaction method in an ambient condition. The physicochemical properties such as phase purity, elemental composition, and morphology of the materials were systematically investigated. The temperature-dependent photoluminescence (PL) properties of the BYSO:8 mol% Mn4+ (i.e., BYSO:8Mn4+) phosphor samples were studied. The PL excitation of the phosphors showed a broadband spectrum in the near-ultraviolet region from 300 to 450 nm with a maximum intensity at 353 nm. Under 353 nm excitation, the Mn4+ ions activated phosphors showed a broadband far-red emission in the region of 650–750 nm with a maximum intensity at 694 nm due to the 2Eg4A2g electronic configuration. The BYSO:8Mn4+ phosphors also showed a lower intensity band at 667 nm and the corresponding Commission Internationale de l’Eclairage chromaticity coordinate for the optimized phosphor was (0.653, 0.274) which is more beneficial, especially for the growth process in plants. Additionally, the optimized BYSO:8Mn4+ phosphor maintained good thermal PL behavior and its related binding energy value was 0.29 eV. Considering these good benefits from the BYSO:8Mn4+ phosphor, we further fabricated a red light-emitting device to demonstrate its potential applicability in solid-state lighting. Also, the as-prepared polydimethylsiloxane composite films demonstrated their suitability for flexible display and anti-counterfeiting applications in harsh environmental conditions.

  • 133

    Synthesis and emission enhancement of intrinsic green-emitting materials for versatile applications

    Abstract

    The intrinsic green-emitting Sr2Sb2O7 phosphors with an orthorhombic structure were synthesized. Meanwhile, the doping of Bi3+ ions greatly enhanced the luminescent properties of Sr2Sb2O7 material by increasing the particle size and supplying the 3P1 → 1S0 emission. The strong green-emitting Sr2Sb2O7:Bi3+ phosphors with excellent moisture resistance and structural stability can be used for some practical applications. The packaged light-emitting diode (LED) devices based on the Sr2Sb2O7:Bi3+ phosphors with and without commercial phosphors were fabricated. Practically, the white LED device exhibited a warm white emission with the color rendering index and correlated color temperature values of 85.36 and 4185 K, respectively. Besides, the Sr2Sb2O7:Bi3+ security inks with good water resistance were presented. Finally, the prepared materials have also been successfully applied to latent fingerprint detections and flexible films. Therefore, these strong green-emitting materials are suitable for various optical applications.

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  • 132

    An anti-counterfeiting strategy of polydimethylsiloxane flexible light-emitting films based on non-rare-earth Mn4+-activated Ba2LaTaO6 phosphors

    Abstract

    Luminescent materials have been widely utilized for anti-counterfeiting applications due to their good feasibility for tunable optical properties. Herein, an anti-counterfeiting strategy based on polydimethylsiloxane (PDMS) flexible light-emitting films is reported. At first, tetravalent manganese (Mn4+)-activated Ba2LaTaO6 phosphors were synthesized by a high-temperature solid-state reaction. The optimal doping concentration of Mn4+ was estimated to be about 0.3 mol% while the quantum yield and color purity were found to be as high as 30.74% and 96.67%, respectively. Afterward, the thermal stability was analyzed based on the temperature-dependent photoluminescence emission spectra and decay curves. Eventually, the optimal sample-convert PDMS flexible films with the ease of operation and good reusability were fabricated and their security level was further boosted by the cooperation of multi-colored and special characters. It is believed that this work can offer valuable information for the construction of a high-level security anti-counterfeiting strategy.

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  • 131

    Green synthesis and electrochemical properties of A(3)(PO4)(2) (A = Mn, Zn, and Co) hydrates for supercapacitors with long-term cycling stability

    Abstract

    Energy storage materials are currently considered to promote the development of life and economy in a society with high energy consumption. Particularly, supercapacitors play a significant role in providing a sustainable human society as a kind of green energy storage system. Recently, most researchers mainly focus on improving the electrochemical properties of electrode materials. In light of cost-effective and discharged pollutants, eco-friendly and simple-operated synthesis is an advanced option to fabricate high-energy storage electrode materials. Herein, a green one-step strategy is introduced to prepare a series of A3(PO4)2 (A = Mn, Zn, and Co) hydrates at room temperature along with the characterization in terms of their phase structure, morphology, and electrochemical properties for potential high-performance supercapacitor electrodes. Interestingly, the Co3(PO4)2·8H2O electrode delivers a good specific capacity value of 210.67 mAh g−1 (specific capacitance value of 1516.8 F g−1) with a high voltage of 0.5 V under the current density of 1 A g−1. Moreover, the constructed pouch-type device exhibits an outstanding cycling stability of ∼90.53% after the following 24000 cycles. In addition, the energy density of the fabricated device is estimated to be 33.44 Wh kg−1 while the maximum power density is found to be about 3750 W kg−1. This work suggests that the A3(PO4)2 hydrates are very promising as excellent electrodes for supercapacitors with ultra-long cycling stability through a simple and green strategy.

  • 130

    In situ deposited cobalt-magnesium selenates as an advanced electrode for electrochemical energy storage

    Abstract

    Currently, bimetallic selenates have attracted much attention as a prominent electrode composite material for supercapacitors owing to their higher redox chemistry and superior electrical conductivity. Herein, we synthesized cobalt-magnesium selenates (CoSeO3−MgSeO4, CMS) via a facile hydrothermal process, followed by selenization. At first, cobalt-magnesium oxide (Co2.32Mg0.68O4, CMO) was in situ prepared by a one-pot hydrothermal method. An investigation on the morphological change was performed by synthesizing the same CMO samples at different growth times by keeping the temperature constant. The CMO electrode designed for 8 h of growth time (CMO-8 h) with an attractive morphology showed a higher areal capacity of 101.7 µAh cm−2 (at 3 mA cm−2) than the other CMO electrodes prepared for 6 and 10 h. Further exalted performance was achieved by the selenization of the CMO-8 h sample to form the CMS material. At 3 mA cm−2, the resulted CMS exhibited nearly three times higher capacity, i.e., 385.4 µAh cm−2, than the CMO-8 h electrode. Additionally, an asymmetric cell fabricated with CMS as a positive electrode also revealed good energy storage performance. Within the applied voltage between 0 and 1.5 V, the asymmetric cell demonstrated maximum energy density of 0.159 mWh cm−2 (18.6 Wh kg−1) and maximum power density of 18.47 mW cm−2 (1938 W kg−1), respectively. Thus, novel magnesium-based metal selenates can act as an efficient electrode for energy storage.

  • 129

    Customization of novel double-perovskite (Ca,Sr)(2)InNbO6:Mn4+ red- emitting phosphors for luminescence lifetime thermometers with good relative sensing sensitivity

    Abstract

    Luminescent thermometry with some outstanding advantages of quick response, large measurement range, and good sensing sensitivity has been widely investigated and suggested for practical applications as a kind of potential technique to detect real temperature. Herein, novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ red-emitting phosphors were prepared and further designed for the luminescence lifetime thermometers based on the temperature-dependent decay curves. At first, the crystal structure, morphology, and some luminescent properties (i.e., photoluminescence (PL) emission spectrum, concentration quenching mechanism, crystal field strength, chromaticity coordinate, color purity, quantum yield, thermal stability, and decay curve) of the Ca2InNbO6:Mn4+ and Sr2InNbO6:Mn4+ phosphors were systematically analyzed and compared. Afterward, it revealed that the PL properties of Ca2InNbO6:Mn4+ phosphors were excellent compared to Sr2InNbO6:Mn4+ phosphors owing to the stronger crystal field strength of Mn4+ ion. Most interestingly, the relative sensing sensitivities of the Ca2InNbO6:Mn4+ and Sr2InNbO6:Mn4+ phosphors were estimated as high as 3.30 % and 4.25 % K−1 with the low-temperature uncertainty of 0.11 and 0.09 K, respectively, indicating that the resultant novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ phosphors could be proposed for luminescence lifetime thermometers with high sensing sensitivity.

  • 128

    Co2Mo3O8/Co3O4 micro-flowers architectured material for high-performance supercapacitor electrodes

    Abstract

    Engineering novel nano/microarchitectures has attracted great attention because they can provide conductive, morphological, and remarkable electrochemical properties in energy storage and energy conversion fields. Herein, the Co2Mo3O8/Co3O4 (CMO/CO) micro-flower-like architectures were prepared via a simple one-step hydrothermal technique. The CMO/CO-based electrode samples were investigated at different reaction temperatures of 120, 150, and 180 °C. The prepared CMO/CO-150 material revealed a large specific surface area (108.57 m2 g−1). The excellent specific capacity value of 301 mAh g−1 (2142 F g−1) at 1 A g−1 of current density was obtained by the optimized CMO/CO-150 sample. Moreover, after successfully performing 5000 cycles at 20 mA cm−2, the CMO/CO electrode represented a capacity retention of 92% with 99% coulombic efficiency. Additionally, the designed pouch-like asymmetric supercapacitor (ASC) with the optimized CMO/CO-150 material and activated carbon material delivered high energy and power density values of 34.38 Wh kg−1 and 2987.07 W kg−1, respectively. For testing practical applications, the fabricated ASC device was also employed to power portable electronic devices. Consequently, the achieved outstanding electrochemical results suggest that CMO/CO electrodes are favorable material for energy storage applications.

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  • 127

    The development of NiCo2O4/PVP/PANI heterogeneous nanocomposites as an advanced battery-type electrode material for high-performing supercapacitor application

    Abstract

    Recently, various electroactive materials composed of binary transition metal oxides (TMOs), and conducting polymers have been extensively studied, with the materials demonstrating great potential in high-performing battery-type electrodes. Furthermore, the development of heterogeneous nanocomposites is a versatile approach because of their well-defined surface morphology and the significant synergistic effect of the various species. In this study, NiCo2O4 (NCO) combined with polyvinyl pyrrolidone (PVP) and polyaniline (PANI) hybrid nanocomposites of NCO/PVP/PANI are newly developed using a facile hydrothermal method. The NCO in combination with PVP and PANI species provides the interconnected hierarchical characteristics by offering large electroactive sites that facilitate the charge transfer. The NCO/PVP/PANI1.5 nanocomposites had a high areal capacity of 698.44 µAh cm−2 at a current density of 4 mA cm–2 and a remarkable capacitance retention of 86 % over 4,000 galvanostatic charge/discharge (GCD) cycles owing to its excellent synergistic effect of the rich faradaic redox reaction kinetics of metallic species, and highly conductive materials. Moreover, the proposed NCO/PVP/PANI1.5 battery-type positive electrode was successfully assembled with an activated carbon negative electrode, resulting a hybrid device with a high energy density of 27.60 Wh kg−1 at a power density of 874.9 W kg−1 and excellent cycling stability. This research holds the significant promise for advanced heterogeneous materials in energy storage systems by describing the newly developed nanocomposites.

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  • 126

    Preparation and characterization of acid-treated multiwalled carbon nanotubes interlinked nickel vanadate microcomposites for lithium-ion batteries

    Summary

    Vanadium-based hybrid metal oxides have a crystalline layer structure and excellent kinetics for high-power-density lithium (Li)-ion batteries. Different oxidation levels and harmonizing chemistry of vanadium need a cost-effective and robust integration approach for the proportion of their form and surface benefits. One of the most attractive methodologies for obtaining pure phase and unique development over varying temperature and pressure conditions is to use hydrothermal technique. Herein, a simple one-pot hydrothermal procedure is used to make the acid-treated multiwalled carbon nanotubes (AMWCNTs) decorated on Ni3V2O8 (NVO) microspheres (MSs). The synthesized AMWCNTs interlinked NVO (NVO@AMWCNTs) MS composite electrode delievers significantly improved Li-ion storage capacities when employed as a negative electrode. At 100 mA g−1, the NVO@AMWCNTs MS composite electrode exhibits a specific capacity of 609.6 mA h g−1 as well as excellent cycling stability of 306.6 mA h g−1 at 1000 mA g−1. The improved electrochemical properties are mainly owing to the large surface area (78.72 m2 g−1), high porosity of connected MSs, and outstanding cooperative chemistry between the NVO and AMWCNTs. The porous structure and high surface area of NVO@AMWCNTs MS composite material allow more voids to adjust the massive amount of Li+ ions in the charge-discharge process. This beneficial composition enhances Li+ ion diffusivity and electrical conductivity by increasing the interface area between the electrolyte and electrode, the specific surface area of the electrodes, and the electrolyte absorption.

  • 125

    Planar and dendrite-free zinc deposition enabled by exposed crystal plane optimization of zinc anode

    Abstract

    The low Coulombic efficiency and limited cycle life of zinc (Zn) metal anode resulting from the severe side reactions and dendrite growth are the major bottlenecks restricting the commercial applications of rechargeable aqueous Zn metal batteries (ZMBs). Considering that the crystal orientation of the electrode surface determines the growth direction of the newly deposited metal, however, limited by the crystal heterogeneity of commercial Zn foil, it can easily lead to inhomogeneous deposition morphology. Therefore, Zn electrode with more exposed (002) plane is considered as an effective strategy for planar and dendrite-free Zn deposition. In this review, we first provide the advantages of the preferred Zn (002) plane for achieving flat Zn deposition and elucidate the effect of electrode surface crystal orientation on Zn metal deposition behavior by correlating crystallography and deposition morphology. Then, we summarize the recent progress in the design and optimization strategies for directional deposition of Zn metal along the (002) orientation. Finally, the challenges, potential solutions, and perspectives for further exploration of planar and dendrite-free Zn deposition are proposed, which are expected to spur more insightful works toward advanced aqueous ZMBs.

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