Displaying publications 1 - 20 of 73 in total

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  1. Zeng D, Zhou T, Ong WJ, Wu M, Duan X, Xu W, et al.
    ACS Appl Mater Interfaces, 2019 Feb 13;11(6):5651-5660.
    PMID: 30615433 DOI: 10.1021/acsami.8b20958
    Sub-5 nm ultra-fine iron phosphide (FeP) nano-dots-modified porous graphitic carbon nitride (g-C3N4) heterojunction nanostructures are successfully prepared through the gas-phase phosphorization of Fe3O4/g-C3N4 nanocomposites. The incorporation of zero-dimensional (0D) ultra-small FeP nanodots co-catalysts not only effectively facilitate charge separation but also serve as reaction active sites for hydrogen (H2) evolution. Herein, the strongly coupled FeP/g-C3N4 hybrid systems are employed as precious-metal-free photocatalysts for H2 production under visible-light irradiation. The optimized FeP/g-C3N4 sample displays a maximum H2 evolution rate of 177.9 μmol h-1 g-1 with the apparent quantum yield of 1.57% at 420 nm. Furthermore, the mechanism of photocatalytic H2 evolution using 0D/2D FeP/g-C3N4 heterojunction interfaces is systematically corroborated by steady-state photoluminescence (PL), time-resolved PL spectroscopy, and photoelectrochemical results. Additionally, an increased donor density in FeP/g-C3N4 is evidenced from the Mott-Schottky analysis in comparison with that of parent g-C3N4, signifying the enhancement of electrical conductivity and charge transport owing to the emerging role of FeP. The density functional theory calculations reveal that the FeP/g-C3N4 hybrids could act as a promising catalyst for the H2 evolution reaction. Overall, this work not only paves a new path in the engineering of monodispersed FeP-decorated g-C3N4 0D/2D robust nanoarchitectures but also elucidates potential insights for the utilization of noble-metal-free FeP nanodots as remarkable co-catalysts for superior photocatalytic H2 evolution.
  2. Zainol Abidin MN, Goh PS, Said N, Ismail AF, Othman MHD, Hasbullah H, et al.
    ACS Appl Mater Interfaces, 2020 Jul 22;12(29):33276-33287.
    PMID: 32589391 DOI: 10.1021/acsami.0c08947
    The development of wearable artificial kidney demands an efficient dialysate recovery, which relies upon the adsorption process. This study proposes a solution to solve the problem of competitive adsorption between the uremic toxins by employing two adsorptive components in a membrane separation process. Dual-layer hollow fiber (DLHF) membranes, which are composed of a polysulfone (PSf)/activated carbon (AC) inner layer and a PSf/poly(methyl methacrylate) (PMMA) outer layer, were prepared for co-adsorptive removal of creatinine and urea from aqueous solution. The DLHF membranes were characterized in terms of morphological, physicochemical, water transport, and creatinine adsorption properties. The membrane was then subjected to an ultrafiltration adsorption study for performance evaluation. The incorporation of AC in membrane, as confirmed by microscopic and surface analyses, has improved the pure water flux up to 25.2 L/(m2 h). A membrane with optimum AC loading (9 wt %) demonstrated the highest maximum creatinine adsorption capacity (86.2 mg/g) based on the Langmuir adsorption isotherm model. In the ultrafiltration adsorption experiment, the membrane removed creatinine and urea with a combined average percent removal of 29.3%. Moreover, the membrane exhibited creatinine and urea uptake recoveries of 98.8 and 81.2%, respectively. The combined action of PMMA and AC in the PSf DLHF membrane has made the adsorption of multiple uremic toxins possible during dialysate recovery.
  3. Yang Q, Cai YY, Zhu ZY, Sun LX, Choo YSL, Zhang QG, et al.
    ACS Appl Mater Interfaces, 2020 Jun 03;12(22):24806-24816.
    PMID: 32396331 DOI: 10.1021/acsami.0c05411
    The development of anion exchange membranes (AEMs) is hindered by the trade-off of ionic conductivity, alkaline stability, and mechanical properties. Tröger's base polymers (Tb-polymers) are recognized as promising membrane materials to overcome these obstacles. Herein, the AEMs made from Tb-poly(crown ether)s (Tb-PCEs) show good comprehensive performance. The influence of crown ether on the conductivity and alkaline stability of AEMs has been investigated in detail. The formation of hydronium ion-crown ether complexes and an obvious microphase-separated structure formed by the existence of crown ether can enhance the conductivity of the AEMs. The maximum OH- conductivity of 141.5 mS cm-1 is achieved from the Tb-PCEs based AEM (Tb-PCE-1) at 80 °C in ultrapure water. The ion-dipole interaction of the Na+ with crown ether can protect the quaternary ammonium from the attack of OH- to improve the alkaline stability of AEMs. After 675 h of alkaline treatment, the OH- conductivity of Tb-PCE-1 decreases by only 6%. The Tb-PCE-1-based single cell shows a peak power density of 0.202 W cm-2 at 80 °C. The prominent physicochemical properties are attributed to the well-developed microstructure of the Tb-PCEs, as revealed by TEM, AFM, and SAXS observations.
  4. Yan J, Cai Y, Zhang H, Han M, Liu X, Chen H, et al.
    ACS Appl Mater Interfaces, 2024 Feb 14;16(6):7883-7893.
    PMID: 38299449 DOI: 10.1021/acsami.3c17947
    Effective heat dissipation and real-time temperature monitoring are crucial for ensuring the long-term stable operation of modern, high-performance electronic products. This study proposes a silicon rubber polydimethylsiloxane (PDMS)-based nanocomposite with a rapid thermal response and high thermal conductivity. This nanocomposite enables both rapid heat dissipation and real-time temperature monitoring for high-performance electronic products. The reported material primarily consists of a thermally conductive layer (Al2O3/PDMS composites) and a reversible thermochromic layer (organic thermochromic material, graphene oxide, and PDMS nanocoating; OTM-GO/PDMS). The thermal conductivity of OTM-GO/Al2O3/PDMS nanocomposites reached 4.14 W m-1 K-1, reflecting an increase of 2200% relative to that of pure PDMS. When the operating temperature reached 35, 45, and 65 °C, the surface of OTM-GO/Al2O3/PDMS nanocomposites turned green, yellow, and red, respectively, and the thermal response time was only 30 s. The OTM-GO/Al2O3/PDMS nanocomposites also exhibited outstanding repeatability and maintained excellent color stability over 20 repeated applications.
  5. Xi Loh EY, Fauzi MB, Ng MH, Ng PY, Ng SF, Ariffin H, et al.
    ACS Appl Mater Interfaces, 2018 Nov 21;10(46):39532-39543.
    PMID: 30372014 DOI: 10.1021/acsami.8b16645
    The evaluation of the interaction of cells with biomaterials is fundamental to establish the suitability of the biomaterial for a specific application. In this study, the properties of bacterial nanocellulose/acrylic acid (BNC/AA) hydrogels fabricated with varying BNC to AA ratios and electron-beam irradiation doses were determined. The manner these hydrogel properties influence the behavior of human dermal fibroblasts (HDFs) at the cellular and molecular levels was also investigated, relating it to its application both as a cell carrier and wound dressing material. Swelling, hardness, adhesive force (wet), porosity, and hydrophilicity (dry) of the hydrogels were dependent on the degree of cross-linking and the amount of AA incorporated in the hydrogels. However, water vapor transmission rate, pore size, hydrophilicity (semidry), and topography were similar between all formulations, leading to a similar cell attachment and proliferation profile. At the cellular level, the hydrogel demonstrated rapid cell adhesion, maintained HDFs viability and morphology, restricted cellular migration, and facilitated fast transfer of cells. At the molecular level, the hydrogel affected nine wound-healing genes (IL6, IL10, MMP2, CTSK, FGF7, GM-CSF, TGFB1, COX2, and F3). The findings indicate that the BNC/AA hydrogel is a potential biomaterial that can be employed as a wound-dressing material to incorporate HDFs for the acceleration of wound healing.
  6. Wang D, Wong SI, Sunarso J, Xu M, Wang W, Ran R, et al.
    ACS Appl Mater Interfaces, 2021 May 05;13(17):20105-20113.
    PMID: 33886260 DOI: 10.1021/acsami.1c02502
    Hydrocarbon-fueled solid oxide fuel cells (SOFCs) that can operate in the intermediate temperature range of 500-700 °C represent an attractive SOFC device for combined heat and power applications in the industrial market. One of the ways to realize such a device relies upon exploiting an in situ steam reforming process in the anode catalyzed by an anti-carbon coking catalyst. Here, we report a new Ni and Ru bimetal-doped perovskite catalyst, Ba(Zr0.1Ce0.7Y0.1Yb0.1)0.9Ni0.05Ru0.05O3-δ (BZCYYbNRu), with enhanced catalytic hydrogen production activity on n-butane (C4H10), which can resist carbon coking over extended operation durations. Ru in the perovskite lattice inhibits Ni precipitation from perovskite, and the high water adsorption capacity of proton conducting perovskite improves the coking resistance of BZCYYbNRu. When BZCYYbNRu is used as a steam reforming catalyst layer on a Ni-YSZ-supported anode, the single fuel cell not only achieves a higher power density of 1113 mW cm-2 at 700 °C under a 10 mL min-1 C4H10 continuous feed stream at a steam to carbon (H2O/C) ratio of 0.5 but also shows a much better operational stability for 100 h at 600 °C compared with those reported in the literature.
  7. Walle KZ, Musuvadhi Babulal L, Wu SH, Chien WC, Jose R, Lue SJ, et al.
    ACS Appl Mater Interfaces, 2021 Jan 20;13(2):2507-2520.
    PMID: 33406841 DOI: 10.1021/acsami.0c17422
    Although solid-state Li-metal batteries (LMBs) featuring polymer-based solid electrolytes might one day replace conventional Li-ion batteries, the poor Li-ion conductivity of solid polymer electrolytes at low temperatures has hindered their practical applications. Herein, we describe the first example of using a co-precipitation method in a Taylor flow reactor to produce the metal hydroxides of both the Ga/F dual-doped Li7La3Zr2O12 (Ga/F-LLZO) ceramic electrolyte precursors and the Li2MoO4-modified Ni0.8Co0.1Mn0.1O2 (LMO@T-LNCM 811) cathode materials for LMBs. The Li/Nafion (LiNf)-coated Ga/F-LLZO (LiNf@Ga/F-LLZO) ceramic filler was finely dispersed in the poly(vinylidene fluoride)/polyacrylonitrile/lithium bis(trifluoromethanesulfonimide)/succinonitrile matrix to give a trilayer composite polymer electrolyte (denoted "Tri-CPE") through a simple solution-casting. The bulk ionic conductivity of the Tri-CPE at room temperature was approximately 4.50 × 10-4 S cm-1 and exhibited a high Li+ ion transference number (0.84). It also exhibits a broader electrochemical window of 1-5.04 V versus Li/Li+. A full cell based on a CR2032 coin cell containing the LMO@T-LNCM811-based composite cathode, when cycled under 1 C/1 C at room temperature for 300 cycles, achieved an average Columbic efficiency of 99.4% and a capacity retention of 89.8%. This novel fabrication strategy for Tri-CPE structures has potential applications in the preparation of highly safe high-voltage cathodes for solid-state LMBs.
  8. Tung J, Ching JY, Ng YM, Tew LS, Khung YL
    ACS Appl Mater Interfaces, 2017 Sep 13;9(36):31083-31094.
    PMID: 28832115 DOI: 10.1021/acsami.7b08343
    The grafting of cyclopropylamine onto a silicon (100) hydride (Si-H) surface via a ring-opening mechanism using UV photoionization is described here. In brief, radicals generated from the Si-H surface upon UV irradiation were found to behave in classical hydrogen abstraction theory manner by which the distal amine group was first hydrogen abstracted and the radical propagated down to the cyclopropane moiety. This subsequently liberated the strained bonds of the cyclopropane group and initiated the surface grafting process, producing a thin film approximately 10-15 nm in height. Contact angle measurements also showed that such photoionization irradiation had yielded an extremely hydrophilic surface (∼21.3°) and X-ray photoelectron spectroscopy also confirmed the coupling was through the Si-C linkage. However, when the surface underwent high-temperature hydrosilylation (>160 °C), the reaction proceeded predominantly through the nucleophilic NH2 group to form a Si-N linkage to the surface. This rendered the surface hydrophobic and hence suggested that the Si-H homolysis model may not be the main process. To the best of our knowledge, this was the first attempt reported in the literature to use photoionization to directly graft cyclopropylamine onto a silicon surface and in due course generate a highly rich NH-terminated surface that was found to be highly bioactive in promoting cell viability on the basis of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide studies.
  9. Tan KH, Chen YW, Van CN, Wang H, Chen JW, Lim FS, et al.
    ACS Appl Mater Interfaces, 2019 Jan 09;11(1):1655-1664.
    PMID: 30561192 DOI: 10.1021/acsami.8b17758
    The ability of band offsets at multiferroic/metal and multiferroic/electrolyte interfaces in controlling charge transfer and thus altering the photoactivity performance has sparked significant attention in solar energy conversion applications. Here, we demonstrate that the band offsets of the two interfaces play the key role in determining charge transport direction in a downward self-polarized BFO film. Electrons tend to move to BFO/electrolyte interface for water reduction. Our experimental and first-principle calculations reveal that the presence of neodymium (Nd) dopants in BFO enhances the photoelectrochemical performance by reduction of the local electron-hole pair recombination sites and modulation of the band gap to improve the visible light absorption. This opens a promising route to the heterostructure design by modulating the band gap to promote efficient charge transfer.
  10. Sun H, Chen G, Sunarso J, Dai J, Zhou W, Shao Z
    ACS Appl Mater Interfaces, 2018 May 23;10(20):16939-16942.
    PMID: 29741862 DOI: 10.1021/acsami.8b03702
    An abundant, highly active, and durable oxygen evolution reaction (OER) electrocatalyst is an enabling component for a more sustainable energy future. We report, herein, a molybdenum and niobium codoped B-site-ordered double perovskite oxide with a compositional formula of Ba2CoMo0.5Nb0.5O6-δ (BCMN) as an active and robust catalyst for OER in an alkaline electrolyte. BCMN displayed a low overpotential of 445 mA at a current density of 10 mA cm-2disk. BCMN also showed long-term stability in an alkaline medium. This work hints toward the possibility of combining a codoping approach with double perovskite structure formation to achieve significant enhancement in the OER performance.
  11. Steiner JD, Cheng H, Walsh J, Zhang Y, Zydlewski B, Mu L, et al.
    ACS Appl Mater Interfaces, 2019 Oct 16;11(41):37885-37891.
    PMID: 31589393 DOI: 10.1021/acsami.9b14729
    Elemental doping represents a prominent strategy to improve interfacial chemistry in battery materials. Manipulating the dopant spatial distribution and understanding the dynamic evolution of the dopants at the atomic scale can inform better design of the doping chemistry for batteries. In this work, we create a targeted hierarchical distribution of Ti4+, a popular doping element for oxide cathode materials, in LiNi0.8Mn0.1Co0.1O2 primary particles. We apply multiscale synchrotron/electron spectroscopy and imaging techniques as well as theoretical calculations to investigate the dynamic evolution of the doping chemical environment. The Ti4+ dopant is fully incorporated into the TMO6 octahedral coordination and is targeted to be enriched at the surface. Ti4+ in the TMO6 octahedral coordination increases the TM-O bond length and reduces the covalency between (Ni, Mn, Co) and O. The excellent reversibility of Ti4+ chemical environment gives rise to superior oxygen reversibility at the cathode-electrolyte interphase and in the bulk particles, leading to improved stability in capacity, energy, and voltage. Our work directly probes the chemical environment of doping elements and helps rationalize the doping strategy for high-voltage layered cathodes.
  12. She W, Qi T, Cui M, Yan P, Ng SW, Li W, et al.
    ACS Appl Mater Interfaces, 2018 May 02;10(17):14698-14707.
    PMID: 29638107 DOI: 10.1021/acsami.8b01187
    A family of two-dimensional salen-type lanthanide complexes was synthesized through a facile solution diffusion method. The two-dimensional lanthanide complexes were characterized by single-crystal X-ray diffraction (SCXRD) and X-ray photoelectron spectroscopy (XPS) analytical techniques. The SCXRD and XPS analyses reveal that the obtained two-dimensional structures are rich in uncoordinated imine (-CH═N-) groups located on the skeleton of the salen-type organic ligand, which retain strong coordination ability with metal ions. On the basis of this unique feature, a highly dispersed CeO2-supported Ni catalyst (Ni/CeO2-CAS) with highly strong metal-support interaction was first synthesized via a coordination-assisted synthesis (CAS) method, which exhibits a much better catalytic activity in the hydrogenation of nitrobenzene than the traditional Ni/CeO2-IWI catalyst prepared by incipient wetness impregnation (IWI). The origin of the improved catalytic activity of Ni/CeO2-CAS as well as the role of Ni@Ce-H2salen was revealed by using diverse characterizations. On the basis of the comparative characterization results, the superior catalytic performance of Ni/CeO2-CAS to Ni/CeO2-IWI could have resulted from the smaller and highly dispersed Ni nanoparticulates, the intensified Ni-CeO2 interaction, the enhanced NiO reducibility, and the higher concentration of oxygen vacancies, favoring the H2 dissociation and adsorption of the nitrobenzene reactant. The Ni/CeO2-CAS catalyst also exhibits high catalytic performance for reduction of diverse nitroarenes to their corresponding functionalized arylamines. We anticipated that this coordination-assisted strategy may provide a new way for preparing other highly oxide-supported catalysts with potential applications in various catalytic reactions.
  13. She S, Yu J, Tang W, Zhu Y, Chen Y, Sunarso J, et al.
    ACS Appl Mater Interfaces, 2018 Apr 11;10(14):11715-11721.
    PMID: 29546981 DOI: 10.1021/acsami.8b00682
    Perovskite oxide is an attractive low-cost alternative catalyst for oxygen evolution reaction (OER) relative to the precious metal oxide-based electrocatalysts (IrO2 and RuO2). In this work, a series of Sr-doped La-based perovskite oxide catalysts with compositions of La1- xSr xFeO3-δ ( x = 0, 0.2, 0.5, 0.8, and 1) are synthesized and characterized. The OER-specific activities in alkaline solution increase in the order of LaFeO3-δ (LF), La0.8Sr0.2FeO3-δ (LSF-0.2), La0.5Sr0.5FeO3-δ (LSF-0.5), SrFeO3-δ (SF), and La0.2Sr0.8FeO3-δ (LSF-0.8). We establish a direct correlation between the enhancement in the specific activity and the amount of surface oxygen vacancies as well as the surface Fe oxidation states. The improved specific activity for LSF-0.8 is clearly linked to the optimum amount of surface oxygen vacancies and surface Fe oxidation states. We also find that the OER performance stability is a function of the crystal structure and the deviation in the surface La and/or Sr composition(s) from their bulk stoichiometric compositions. The cubic structure and lower deviation, as is the case for LSF-0.8, led to a higher OER performance stability. These surface performance relations provide a promising guideline for constructing efficient water oxidation.
  14. Shahiduzzaman M, Chen B, Akhtaruzzaman M, Wang L, Fukuhara H, Tomita K, et al.
    ACS Appl Mater Interfaces, 2021 Nov 17;13(45):53758-53766.
    PMID: 34735118 DOI: 10.1021/acsami.1c13793
    In this study, the spontaneous microstructure tuning of TiO2 was observed by aging the ethanol/water TiO2 paste for up to 20 days at ambient conditions. A dynamic light scattering study reveals that it formed the outstanding reproducible TiO2 microstructure with a ∼200 nm average particle size and stabilizes in 6 to 20 days under an ambient atmosphere. Interestingly, the as-deposited day 15 sample spontaneously changed its crystallinity upon keeping the paste at ambient conditions; meanwhile the day 0 sample showed an amorphous structure. A dense, uniform, and stable TiO2 electrode was cast on a fluorine doped-tin oxide substrate using the electrospray technique. We exploit the spontaneous evolution of the TiO2 nanopowder to revisit the fabrication procedure of the TiO2 photoelectrode for dye-sensitized solar cells (DSSCs). The controlled microstructure TiO2 film was used in DSSCs, which, to the best of our knowledge, achieved the highest power conversion efficiency of 9.65% using N719 dye in sensitizing the TiO2 photoanode.
  15. Shah MT, Balouch A, Rajar K, Sirajuddin, Brohi IA, Umar AA
    ACS Appl Mater Interfaces, 2015 Apr 1;7(12):6480-9.
    PMID: 25785883 DOI: 10.1021/am507778a
    Magnetite nanoparticles were successfully synthesized and effectively employed as heterogeneous catalyst for hydrogenation of ketone moiety to alcohol moiety by NaBH4 under the microwave radiation process. The improvement was achieved in percent recovery of isopropyl alcohol by varying and optimizing reaction time, power of microwave radiations and amount of catalyst. The catalytic study revealed that acetone would be converted into isopropyl alcohol (IPA) with 99.5% yield in short period of reaction time, using 10 μg of magnetite NPs (Fe3O4). It was observed that the catalytic hydrogenation reaction, followed second-order of reaction and the Langmuir-Hinshelwood kinetic mechanism, which elucidated that both reactants get adsorb onto the surface of silica coated magnetite nanocatalyst to react. Consequently, the rate-determining step was the surface reaction of acetone and sodium borohydride. The current study revealed an environment friendly conversion of acetone to IPA on the basis of its fast, efficient, and highly economical method of utilization of microwave irradiation process and easy catalyst recovery.
  16. Selvakumar M, Srivastava P, Pawar HS, Francis NK, Das B, Sathishkumar G, et al.
    ACS Appl Mater Interfaces, 2016 Feb 17;8(6):4086-100.
    PMID: 26799576 DOI: 10.1021/acsami.5b11723
    Guided bone regeneration (GBR) scaffolds are futile in many clinical applications due to infection problems. In this work, we fabricated GBR with an anti-infective scaffold by ornamenting 2D single crystalline bismuth-doped nanohydroxyapatite (Bi-nHA) rods onto segmented polyurethane (SPU). Bi-nHA with high aspect ratio was prepared without any templates. Subsequently, it was introduced into an unprecedented synthesized SPU matrix based on dual soft segments (PCL-b-PDMS) of poly(ε-caprolactone) (PCL) and poly(dimethylsiloxane) (PDMS), by an in situ technique followed by electrospinning to fabricate scaffolds. For comparison, undoped pristine nHA rods were also ornamented into it. The enzymatic ring-opening polymerization technique was adapted to synthesize soft segments of PCL-b-PDMS copolymers of SPU. Structure elucidation of the synthesized polymers is done by nuclear magnetic resonance spectroscopy. Sparingly, Bi-nHA ornamented scaffolds exhibit tremendous improvement (155%) in the mechanical properties with excellent antimicrobial activity against various human pathogens. After confirmation of high osteoconductivity, improved biodegradation, and excellent biocompatibility against osteoblast cells (in vitro), the scaffolds were implanted in rabbits by subcutaneous and intraosseous (tibial) sites. Various histological sections reveal the signatures of early cartilage formation, endochondral ossification, and rapid bone healing at 4 weeks of the critical defects filled with ornamented scaffold compared to SPU scaffold. This implies osteogenic potential and ability to provide an adequate biomimetic microenvironment for mineralization for GBR of the scaffolds. Organ toxicity studies further confirm that no tissue architecture abnormalities were observed in hepatic, cardiac, and renal tissue sections. This finding manifests the feasibility of fabricating a mechanically adequate nanofibrous SPU scaffold by a biomimetic strategy and the advantages of Bi-nHA ornamentation in promoting osteoblast phenotype progression with microbial protection (on-demand) for GBR applications.
  17. Saidi NM, Omar FS, Numan A, Apperley DC, Algaradah MM, Kasi R, et al.
    ACS Appl Mater Interfaces, 2019 Aug 21;11(33):30185-30196.
    PMID: 31347822 DOI: 10.1021/acsami.9b07062
    To overcome the critical limitations of liquid-electrolyte-based dye-sensitized solar cells, quasi-solid-state electrolytes have been explored as a means of addressing long-term device stability, albeit with comparatively low ionic conductivities and device performances. Although metal oxide additives have been shown to augment ionic conductivity, their propensity to aggregate into large crystalline particles upon high-heat annealing hinders their full potential in quasi-solid-state electrolytes. In this work, sonochemical processing has been successfully applied to generate fine Co3O4 nanoparticles that are highly dispersible in a PAN:P(VP-co-VAc) polymer-blended gel electrolyte, even after calcination. An optimized nanocomposite gel polymer electrolyte containing 3 wt % sonicated Co3O4 nanoparticles (PVVA-3) delivers the highest ionic conductivity (4.62 × 10-3 S cm-1) of the series. This property is accompanied by a 51% enhancement in the apparent diffusion coefficient of triiodide versus both unmodified and unsonicated electrolyte samples. The dye-sensitized solar cell based on PVVA-3 displays a power conversion efficiency of 6.46% under AM1.5 G, 100 mW cm-2. By identifying the optimal loading of sonochemically processed nanoparticles, we are able to generate a homogenous extended particle network that effectively mobilizes redox-active species through a highly amorphous host matrix. This effect is manifested in a selective 51% enhancement in photocurrent density (JSC = 16.2 mA cm-2) and a lowered barrier to N719 dye regeneration (RCT = 193 Ω) versus an unmodified solar cell. To the best of our knowledge, this work represents the highest known efficiency to date for dye-sensitized solar cells based on a sonicated Co3O4-modified gel polymer electrolyte. Sonochemical processing, when applied in this manner, has the potential to make meaningful contributions toward the ongoing mission to achieve the widespread exploitation of stable and low-cost dye-sensitized solar cells.
  18. Robin Chang YH, Jiang J, Khong HY, Saad I, Chai SS, Mahat MM, et al.
    ACS Appl Mater Interfaces, 2021 Jun 02;13(21):25121-25136.
    PMID: 34008948 DOI: 10.1021/acsami.1c04759
    Transition metal chalcogenides (TMCs) have gained worldwide interest owing to their outstanding renewable energy conversion capability. However, the poor mechanical flexibility of most existing TMCs limits their practical commercial applications. Herein, triggered by the recent and imperative synthesis of highly ductile α-Ag2S, an effective approach based on evolutionary algorithm and ab initio total-energy calculations for determining stable, ductile phases of bulk and two-dimensional Ag
    x
    Se1-x and Ag
    x
    Te1-x compounds was implemented. The calculations correctly reproduced the global minimum bulk stoichiometric P212121-Ag8Se4 and P21/c-Ag8Te4 structures. Recently reported metastable AgTe3 was also revealed but it lacks dynamical stability. Further single-layered screening unveiled two new monolayer P4/nmm-Ag4Se2 and C2-Ag8Te4 phases. Orthorhombic Ag8Se4 crystalline has a narrow, direct band gap of 0.26 eV that increases to 2.68 eV when transforms to tetragonal Ag4Se2 monolayer. Interestingly, metallic P21/c-Ag8Te4 changes to semiconductor when thinned down to monolayer, exhibiting a band gap of 1.60 eV. Present findings confirm their strong stability from mechanical and thermodynamic aspects, with reasonable Vickers hardness, bone-like Young's modulus (E) and high machinability observed in bulk phases. Detailed analysis of the dielectric functions ε(ω), absorption coefficient α(ω), power conversion efficiency (PCE) and refractive index n(ω) of monolayers are reported for the first time. Fine theoretical PCE (SLME method ∼11-28%), relatively high n(0) (1.59-1.93), and sizable α(ω) (104-105 cm-1) that spans the infrared to visible regions indicate their prospects in optoelectronics and photoluminescence applications. Effective strategies to improve the temperature dependent power factor (PF) and figure of merit (ZT) are illustrated, including optimizing the carrier concentration. With decreasing thickness, ZT of p-doped Ag-Se was found to rise from approximately 0.15-0.90 at 300 K, leading to a record high theoretical conversion efficiency of ∼12.0%. The results presented foreshadow their potential application in a hybrid device that combines the photovoltaic and thermoelectric technologies.
  19. Ravikumar A, Panneerselvam P, Morad N
    ACS Appl Mater Interfaces, 2018 Jun 20;10(24):20550-20558.
    PMID: 29792319 DOI: 10.1021/acsami.8b05041
    In this paper, we propose a metal-polydopamine (MPDA) framework with a specific molecular probe which appears to be the most promising approach to a strong fluorescence quencher. The MPDA framework quenching ability toward various organic fluorophore such as aminoethylcoumarin acetate, 6-carboxyfluorescein (FAM), carboxyteramethylrhodamine, and Cy5 are used to establish a fluorescent biosensor that can selectively recognize Hg2+ and Ag+ ions. The fluorescent quenching efficiency was sufficient to achieve more than 96%. The MPDA framework also exhibits different affinities with ssDNA and dsDNA. In addition, the FAM-labeled ssDNA was adsorbed onto the MPDA framework, based on their interaction with the complex formed between MPDA frameworks/ssDNA taken as a sensing platform. By taking advantage of this sensor, highly sensitive and selective determination of Hg2+ and Ag+ ions is achieved through exonuclease III signal amplification activity. The detection limits of Hg2+ and Ag+ achieved to be 1.3 and 34 pM, respectively, were compared to co-existing metal ions and graphene oxide-based sensors. Furthermore, the potential applications of this study establish the highly sensitive fluorescence detection targets in environmental and biological fields.
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