As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

Nanoparticles: Properties, applications and toxicities

A review on g-C3N4-based photocatalysts

Liming Dai,*,†,‡ Yuhua Xue,†,‡ Liangti Qu,* Hyun-Jung Choi, and Jong-Beom Baek* †Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Department of Chemistry, School of Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China School of Energy and Chemical Engineering/Center for Dimension-Controllable Covalent Organic Frameworks, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon, Ulsan, 689-798, South Korea

Metal-free catalysts for oxygen reduction reaction.

This Review focuses on noncovalent functionalization of graphene and graphene oxide with various species involving biomolecules, polymers, drugs, metals and metal oxide-based nanoparticles, quantum dots, magnetic nanostructures, other carbon allotropes (fullerenes, nanodiamonds, and carbon nanotubes), and graphene analogues (MoS2, WS2). A brief description of π–π interactions, van der Waals forces, ionic interactions, and hydrogen bonding allowing noncovalent modification of graphene and graphene oxide is first given. The main part of this Review is devoted to tailored functionalization for applications in drug delivery, energy materials, solar cells, water splitting, biosensing, bioimaging, environmental, catalytic, photocatalytic, and biomedical technologies. A significant part of this Review explores the possibilities of graphene/graphene oxide-based 3D superstructures and their use in lithium-ion batteries. This Review ends with a look at challenges and future prospects of noncovalently modified graph...

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Noncovalent Functionalization of Graphene and Graphene Oxide for Energy Materials, Biosensing, Catalytic, and Biomedical Applications

A thin Fe2TiO5 layer was produced on hematite either by evaporating a TiCl4 solution on FeOOH or by a simple HF-assisted Ti treatment of FeOOH, both followed by annealing. The prepared Fe2TiO5-hematite heterostructure showed a significant enhancement in photocurrent density compared to that of the pristine hematite. For example, the sample after HF-assisted Ti treatment exhibited a significantly enhanced photocurrent of 2.0 mA/cm(2) at 1.23 V vs RHE. Moreover, the performance of the Fe2TiO5-hematite heterostructure can be further improved by coupling with Co-Pi catalysts, achieving a higher photocurrent of 2.6 mA/cm(2) at 1.23 V vs RHE. Synchrotron-based soft X-ray absorption spectroscopy analyses clearly revealed the existence of an Fe2TiO5 structure on hematite forming a heterojunction, which reduced the photogenerated hole accumulation and then improved the performance.

Thin-Layer Fe2TiO5 on Hematite for Efficient Solar Water Oxidation.

High-quality and wafer-scale graphene on insulating gate dielectrics is a prerequisite for graphene electronic applications. For such applications, graphene is typically synthesized and then transferred to a desirable substrate for subsequent device processing. Direct production of graphene on substrates without transfer is highly desirable for simplified device processing. However, graphene synthesis directly on substrates suitable for device applications, though highly demanded, remains unattainable and challenging. Here, we report a simple, transfer-free method capable of synthesizing graphene directly on dielectric substrates at temperatures as low as 600 °C using polycyclic aromatic hydrocarbons as the carbon source. Significantly, N-doping and patterning of graphene can be readily and concurrently achieved by this growth method. Remarkably, the graphene films directly grown on glass attained a small sheet resistance of 550 Ω/sq and a high transmittance of 91.2%. Organic light-emitting diodes (OLEDs)...

Transfer-Free Synthesis of Doped and Patterned Graphene Films

Enhancing light outcoupling in flexible organic light-emitting diodes (FOLEDs) is an important task for increasing their efficiencies for display and lighting applications. Here, a strategy for an angularly and spectrally independent boost in light outcoupling of FOLEDs is demonstrated by using plastic substrates with a low refractive index, consisting of a bioinspired optical coupling layer and a transparent conductive electrode composed of a silver network. The good transmittance to full-color emission (>94% over the whole visible wavelength range), ultralow sheet resistance to carrier injection (<5 Ω sq(-1)), and high tolerance to mechanical bending of the ameliorated plastic substrates synergistically optimize the device performance of FOLEDs. The maximum power efficiencies reach 47, 93, 56, and 52 lm W(-1) for red, green, blue, and white emissions, which are competitive with similarly structured OLEDs fabricated on traditional indium-tin-oxide (ITO) glass. This paradigm for light outcoupling enhancement in ITO-free FOLEDs offers additional features and design freedoms for highly efficient flexible optoelectronics in large-scale and low-cost manufacturing without the need for a high-refractive-index plastic substrate.

Outcoupling-Enhanced Flexible Organic Light-Emitting Diodes on Ameliorated Plastic Substrate with Built-in Indium–Tin-Oxide-Free Transparent Electrode

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2660 wileyonlinelibrary.com efforts devoted to the development of high-performance phosphorescent or thermally activated delayed fl uorescent emitters and novel device architectures, internal quantum effi ciency has already achieved ≈100% for energy conversion due to the fully use of both singlet and triplet states. [ 6–8 ] Unfortunately, one of the major drawbacks of conventional OLEDs is the light confi nement that a high fraction of energy fl ow generated in the emissive materials is trapped as substrate, waveguide (WG), and surface plasmon polariton (SPP) modes in glass substate, organic/transparent indium-tin-oxide (ITO) layers, and metallic rear electrode due to the mismatch of refractive indices in the fl at multilayered structures. [ 9–11 ]

Efficiently releasing the trapped energy flow in white organic light-emitting diodes with multifunctional nanofunnel arrays

In this paper, the Fe3O4/Au nanocomposites were fabricated and employed as surface-enhanced infrared absorption (SEIRA) substrates. The superparamagnetic nature of Fe3O4/Au nanocomposites makes them suitable for controlled magnetic manipulation. The infrared absorption enhancements of Fe3O4/Au composite were improved as the magnetic field intensity increasing both for mercaptobenzoic acid and nitrobenzoic acid probe molecules. When the magnetic field intensities increase to 280 mT, the infrared enhancement could raise up to 3.3 and 10.7 times for -SH and -NO2 groups, respectively. The enhancement is due to the synergy of localized surface plasmon resonance of Au and the magnetism of Fe3O4. Under the strong magnetic field, the superparamagnetic Fe3O4/Au nanoparticles are highly concentrated, leading to the increase number of SEIRA “active sites” and the surface density of Au nanoparticles. The synergistic effects of both Fe3O4 and Au nanoparticles make the composites an excellent SEIRA substrate. In additi...

Shuit-Tong Lee

Papers

Thin-Layer Fe2TiO5 on Hematite for Efficient Solar Water Oxidation.

Transfer-Free Synthesis of Doped and Patterned Graphene Films

Outcoupling-Enhanced Flexible Organic Light-Emitting Diodes on Ameliorated Plastic Substrate with Built-in Indium–Tin-Oxide-Free Transparent Electrode

Efficiently releasing the trapped energy flow in white organic light-emitting diodes with multifunctional nanofunnel arrays

Controllable Fe3O4/Au substrate for surface-enhanced infrared absorption spectroscopy