Shown, I, Samireddi S, Chang Y-C, Putikam R, Chang P-H, Sabbah A, Fu F-Y, Chen W-F, Wu C-I, Yu T-Y, Chung P-W, Lin MC, Chen L-C, Chen K-H.
2018.
Carbon-doped SnS2 nanostructure as a high-efficiency solar fuel catalyst under visible light, 2018. Nature Communications. 9(1):169.
AbstractPhotocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an l-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS2 (SnS2-C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS2 lattice, resulting in different photophysical properties as compared with undoped SnS2. This SnS2-C photocatalyst significantly enhances the CO2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS2-C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO2 reduction under visible light, where the in situ carbon-doped SnS2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.
K.P.O., M, Shown I, Chen L-C, Chen K-H, Tai Y.
2018.
Flexible sensor for dopamine detection fabricated by the direct growth of α-Fe2O3 nanoparticles on carbon cloth, 2018. Applied Surface Science. 427:387-395.
AbstractAbstractPorous α-Fe2O3 nanoparticles are directly grown on acid treated carbon cloth (ACC) using a simple hydrothermal method (denoted as ACC-α-Fe2O3) for employment as a flexible and wearable electrochemical electrode. The catalytic activity of ACC-α-Fe2O3 allowing the detection of dopamine (DA) is systematically investigated. The results showed that the ACC-α-Fe2O3 electrode exhibits impressive electrochemical sensitivity, stability and selectivity for the detection of DA. The detection limit determined with the amperometric method appears to be around 50nM with a linear range of 0.074–113μM. The impressive DA sensing ability of the as prepared ACC-α-Fe2O3 electrode is due to the good electrochemical behavior and high electroactive surface area (19.96cm2) of α-Fe2O3 nanoparticles anchored on the highly conductive ACC. It is worth noting that such remarkable sensing properties can be maintained even when the electrode is in a folded configuration.
Rajeev Gandhi, J, Nehru R, Chen S-M, Sankar R, Bayikadi KS, Sureshkumar P, Chen K-H, Chen L-C.
2018.
Influence of GeP precipitates on the thermoelectric properties of P-type GeTe and Ge0.9−xPxSb0.1Te compounds, 2018. CrystEngComm. 20(41):6449-6457.: The Royal Society of Chemistry
AbstractGermanium telluride (GeTe) is a very well known IV–VI group semiconducting material with the advantageous property of showing metallic conduction, which materializes from its superior carrier concentration (n) (high number of Ge vacancies). A systematic investigation into the thermoelectric properties (TEP) of GeTe was reported by way of carrier concentration (n) engineering. The present investigation focuses on studying the effects of doping (antimony – Sb) and co-doping (phosphorus – P) on the TEP of GeTe. In order to understand the system, we have prepared p-type GeTe and Ge0.9−xPxSb0.1Te (x = 0, 0.01, 0.03, or 0.05) samples via a non-equilibrium solid state melt quenching (MQ) process, followed by hot press consolidation. Temperature dependent synchrotron X-ray diffraction studies reveal a phase transition from rhombohedral to simple cubic in the Ge0.9−xPxSb0.1Te system at 573 K, which is clearly reflected in the TEP. Further high resolution transmission electron microscopy (HRTEM) studies reveal the pseudo-cubic nature of the sample. However, powder X-ray diffraction (PXRD) and field emission scanning electron microscopy (FESEM) images and energy dispersive X-ray spectroscopy (EDX) studies confirm the presence of germanium phosphide (GeP) in all P-doped samples. The presence of a secondary phase and point defects (Sb & P) enhanced the additional scattering effects in the system, which influenced the Seebeck coefficient and thermal conductivity of GeTe. A significant enhancement in the Seebeck coefficient (S) to ∼225 μV K−1 and a drastic reduction in thermal conductivity (κ) to ∼1.2 W mK−1 effectively enhanced the figure-of-merit (ZT) to ∼1.72 at 773 K for Ge0.87P0.03Sb0.1Te, which is a ∼3 fold increase for GeTe. Finally, P co-doped Ge0.9Sb0.1Te demonstrates an enhancement in ZT, making it a good candidate material for power generation applications.
Roy, PK, Haider G, Lin H-I, Liao Y-M, Lu C-H, Chen K-H, Chen L-C, Shih W-H, Liang C-T, Chen Y-F.
2018.
Multicolor Ultralow-Threshold Random Laser Assisted by Vertical-Graphene Network, 2018. Advanced Optical MaterialsAdvanced Optical Materials. 6(16):1800382.: John Wiley & Sons, Ltd
AbstractAbstract Application of lasers is omnipresent in modern-day technology. However, preparation of a lasing device usually requires sophisticated design of the materials and is costly, which may limit the suitable choice of materials and the lasing wavelengths. Random lasers, on the other hand, can circumvent the aforementioned shortcomings with simpler fabrication process, lower processing cost, material flexibility for any lasing wavelengths with lower lasing threshold, providing a roadmap for the design of super-bright lighting, displays, Li-Fi, etc. In this work, ultralow-threshold random laser action from semiconductor nanoparticles assisted by a highly porous vertical-graphene-nanowalls (GNWs) network is demonstrated. The GNWs embedded by the nanomaterials produce a suitable cavity for trapping the optical photons with semiconductor nanomaterials acting as the gain medium. The observed laser action shows ultralow values of threshold energy density ≈10 nJ cm?2 due to the strong photon trapping within the GNWs. The threshold pump fluence can be further lowered to ≈1 nJ cm?2 by coating Ag/SiO2 upon the GNWs due to the combined effect of photon trapping and strong plasmonic enhancement. In view of the growing demand of functional materials and novel technologies, this work provides an important step toward realization of high-performance optoelectronic devices.
Billo, T, Fu F-Y, Raghunath P, Shown I, Chen W-F, Lien H-T, Shen T-H, Lee J-F, Chan T-S, Huang K-Y, Wu C-I, Lin MC, Hwang J-S, Lee C-H, Chen L-C, Chen K-H.
2018.
Ni-Nanocluster Modified Black TiO2 with Dual Active Sites for Selective Photocatalytic CO2 Reduction. Small. 14:1702928–n/a., Number 2
AbstractOne of the key challenges in artificial photosynthesis is to design a photocatalyst that can bind and activate the CO2 molecule with the smallest possible activation energy and produce selective hydrocarbon products. In this contribution, a combined experimental and computational study on Ni-nanocluster loaded black TiO2 (Ni/TiO2[Vo]) with built-in dual active sites for selective photocatalytic CO2 conversion is reported. The findings reveal that the synergistic effects of deliberately induced Ni nanoclusters and oxygen vacancies provide (1) energetically stable CO2 binding sites with the lowest activation energy (0.08 eV), (2) highly reactive sites, (3) a fast electron transfer pathway, and (4) enhanced light harvesting by lowering the bandgap. The Ni/TiO2[Vo] photocatalyst has demonstrated highly selective and enhanced photocatalytic activity of more than 18 times higher solar fuel production than the commercial TiO2 (P-25). An insight into the mechanisms of interfacial charge transfer and product formation is explored.
Fang, S-L, Chou T-chin, Samireddi S, Chen K-H, Chen L-C, Chen W-F.
2017.
Enhanced hydrogen evolution reaction on hybrids of cobalt phosphide and molybdenum phosphide, 2017/03/01. Royal Society open science. 4(3):161016161016-161016.: The Royal Society Publishing
AbstractProduction of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer-Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP(2) crystal phase is formed which enhances the electrochemical activity.
Ebrahimi, M, Samadi M, Yousefzadeh S, Soltani M, Rahimi A, Chou T-chin, Chen L-C, Chen K-H, Moshfegh AZ.
2017.
Improved Solar-Driven Photocatalytic Activity of Hybrid Graphene Quantum Dots/ZnO Nanowires: A Direct Z-Scheme Mechanism, 2017. ACS Sustainable Chemistry & EngineeringACS Sustainable Chemistry & Engineering. 5(1):367-375.: American Chemical Society
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Pathak, A, Chiou GR, Gade NR, Usman M, Mendiratta S, Luo T-T, Tseng TW, Chen J-W, Chen F-R, Chen K-H, Chen L-C, Lu K-L.
2017.
High-κ Samarium-Based Metal–Organic Framework for Gate Dielectric Applications. ACS Appl. Mater. Interfaces. 9(26):21872–21878.
Qorbani, M, Chou T-chin, Lee Y-H, Samireddi S, Naseri N, Ganguly A, Esfandiar A, Wang C-H, Chen L-C, Chen K-H, Moshfegh AZ.
2017.
Multi-porous Co3O4 nanoflakes @ sponge-like few-layer partially reduced graphene oxide hybrids: towards highly stable asymmetric supercapacitors. Journal of Materials Chemistry A. 5:12569-12577.
Lee, C-P, Chen W-F, Billo T, Lin Y-G, Fu F-Y, Samireddi S, Lee C-H, Hwang J-S, Chen K-H, Chen L-C.
2016.
Beaded stream-like CoSe2 nanoneedle array for efficient hydrogen evolution electrocatalysis, 2016. Journal of Materials Chemistry A. 4(12):4553-4561.: The Royal Society of Chemistry
AbstractThe development of earth-abundant and efficient electrocatalysts for the hydrogen evolution reaction (HER) is one of the keys to success for future green energy systems using hydrogen fuel. Nanostructuring of electrocatalysts is a promising way to enhance their electrocatalytic performance in the HER. In this study, pure pyrite-type beaded stream-like cobalt diselenide (CoSe2) nanoneedles are directly formed on flexible titanium foils through treating a cobalt oxide (Co3O4) nanoneedle array template with selenium vapor. The beaded stream-like CoSe2 nanoneedle electrode can drive the HER at a current density of 20 mA cm−2 with a small overpotential of 125 mV. Moreover, the beaded stream-like CoSe2 nanoneedle electrode remains stable in an acidic electrolyte for 3000 cycles and continuously splits water over a period of 18 hours. The enhanced electrochemical activity is facilitated by the unique three-dimensional hierarchical structure, the highly accessible surface active sites, the improved charge transfer kinetics and the highly attractive force between water and the surface of the nanoneedles that exceeds the surface tension of water.
Tran Nguyen, NH, Nguyen TH, Liu Y-ren, Aminzare M, Pham ATT, Cho S, Wong DP, Chen K-H, Seetawan T, Pham NK, Ta HKT, Tran VC, Phan TB.
2016.
Thermoelectric Properties of Indium and Gallium Dually Doped ZnO Thin Films, 2016. ACS Applied Materials & InterfacesACS Applied Materials & Interfaces. 8(49):33916-33923.: American Chemical Society
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