Two efficient blue thermally activated delayed fluorescence compounds, B‐oCz and B‐oTC, composed of ortho‐donor (D)–acceptor (A) arrangement were designed and synthesized. The significant ...intramolecular D–A interactions induce a combined charge transfer pathway and thus achieve small ΔEST and high efficiencies. The concentration quenching can be effectively inhibited in films of these compounds. The blue non‐doped organic light emitting diodes (OLEDs) based on B‐oTC prepared from solution processes shows record‐high external quantum efficiency (EQE) of 19.1 %.
Blue note: Highly efficient blue thermally activated delayed fluorescent (TADF) materials have been developed by using a new design strategy. Solution‐processed, non‐doped blue organic light‐emitting diodes based on these emitters realized record‐high external quantum efficiency of 19.1 %.
•GDP increased slightly under carbon price policies.•Carbon emission intensity decreased within different simulation scenarios.•Energy demand appeared a steady decline after 2017 according to ...discussions.•The alternative interval of carbon price benchmark as 30yuan/tCO2 to 50yuan/tCO2 is suggested.
The prioritized purpose of this dissertation is to put forward a scientific and plausible interval of carbon price benchmark on the unified carbon trading market, of which will be scheduled to be established in the year of 2016. A model named EMD–GARCH that integrated Empirical Mode Decomposition (EMD) with Generalized Autoregressive Conditionally Heteroskedastic (GARCH) together is presented here in order to forecast the carbon price of the five pilots (Shenzhen, Shanghai, Beijing, Guangdong, and Tianjin) in 2016 so as to provide exogenous data for later analysis. For further study, a recursive dynamic Computable General Equilibrium (CGE) model will be structured to explore the impacts on China’s macroeconomics, environmental quality, and energy demand respectively under 8 different simulation scenarios, which are being designed in terms of the aforementioned calculated carbon price outcome. The simulation results illustrate that the unified carbon price policy will exert a comprehensive effect on China in various perspectives that we discussed in this paper. Moreover, regarding the carbon price scenarios, the price level by itself generates a different degree of impacts in improving the environmental quality, decreasing the energy demand, and increasing the macroeconomic growth. Consequently, based on the analysis of those three approaches mix in this study, we suggest the alternative interval of carbon price benchmark in the national unified carbon trading market with a lower bound of 30yuan/tCO2 to an upper bound of 50yuan/tCO2.
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•MOFs-templated approach combining the impregnation method is used to prepare MnOx/Co3O4 nanocomposites.•Interaction between Co3O4 and MnOx improves physicochemical property of ...catalysts.•Optimized MnOx/Co3O4-4h catalyst shows good catalytic performance in chlorobenzene removal.
Chlorinated volatile organic compounds (CVOCs) existing widely in the industries are harmful to the environment and human’s health. It is urgent to develop highly efficient catalysts for their combustion. Herein, a series of porous MnOx/Co3O4 nanocomposites are synthesized by the pyrolysis of Mn@Co-ZIF-67 precursors, in which the Mn ions are introduced by impregnation method. XRD, Raman, ICP-OES, BET, SEM, TEM, XPS, O2-TPD, and H2-TPR have been performed to investigate the as-prepared catalysts’ physicochemical properties. The optimal catalyst MnOx/Co3O4-4h exhibits 90% and 100% chlorobenzene (CB) conversion (1000 ppm, Air, WHSV = 60,000 mL/(g h)) at 334 °C and 350 °C, respectively. And the better catalytic performance over MnOx/Co3O4-4h compared with the pure Co3O4 and other MnOx/Co3O4 nanocomposites mainly ascribes to its porous structures, homogeneous dispersion, optimal Mn/Co molar ratio, more lattice defects, and higher surface OLatt/OAds ratio. Meanwhile, MnOx/Co3O4-4h displays high stability and resistance to moisture. Main intermediates have been further investigated by in situ DRIFT, and the degradation mechanism has been proposed according to the analysis of intermediates.
Using a wet chemical process, a continuous network of silver nanowires was buried at the surface of a transparent polymer (PVA) to form a flexible transparent conductor, which shows high optical ...transparency, low sheet resistance, a smooth surface, and superior mechanical, thermal and chemical stabilities. The composite is a competitive choice for transparent electrodes in OLED and thin film solar cells.
Covalent organic frameworks (COFs), a fast-growing field in crystalline porous materials, have achieved tremendous success in structure development and application exploration over the past decade. ...The vast majority of COFs reported to date are designed according to the basic concept of reticular chemistry, which is rooted in the idea that building blocks are fully connected within the frameworks. We demonstrate here that sub-stoichiometric construction of 2D/3D COFs can be accomplished by the condensation of a hexagonal linker with 4-connected building units. It is worth noting that the partially connected frameworks were successfully reticulated for 3D COFs for the first time, representing the highest BET surface area among imine-linked 3D COFs to data. The unreacted benzaldehydes in COF frameworks can enhance C2H2 and CO2 adsorption capacity and selectivities between C2H2/CH4 and C2H2/CO2 for sub-stoichiometric 2D COFs, while the reserved benzaldehydes control the interpenetrated architectures for the 3D case, achieving a rare non-interpenetrated pts topology for 3D COFs. This work not only paves a new avenue to build new COFs and endows residual function groups with further applications but also prompts redetermination of reticular frameworks in highly connected and symmetrical COFs.
•As a prominent proxy to peer-peer sharing business, Airbnb was chosen as study context.•Airbnb hosts are motivated by eight factors from the financial, social, and cultural ...perspectives.•Micro-entrepreneurial outcomes include financial, social, cultural, and individual gains.•Challenges to Airbnb hosts include risks, lack of privacy, and emotional stress.
This qualitative study explores various aspects of microentrepreneurship in the sharing economy and describes the motivations of people who operate these innovative businesses from financial, social, and cultural perspectives. This study uncovers the positive and negative outcomes of such business activities. Airbnb, a prominent proxy in the peer-to-peer accommodation business, was chosen as the study context and Airbnb hosts interviewed to build a theoretical framework. The results identified eight motivations behind Airbnb hosts’ microentrepreneurial activities: social, financial, and cultural benefit; ease of operation; availability of resources; freedom; flexibility; and excitement about future perspectives. The data also indicated that Airbnb hosts perceive five positive outcomes of their microentrepreneurship: financial gain, social connection, cultural learning, personal growth, and feelings of achievement. In addition, this study found that microentrepreneurship presents challenges to Airbnb hosts, such as risk, lack of privacy, and emotional stress resulting from guest reviews. The theoretical and practical implications are discussed in detail.
Thermally activated delayed fluorescence (TADF) materials that exhibit simultaneously high photoluminescence quantum yield (PLQY), rapid reverse intersystem crossing (RISC), and a high horizontal ...transition dipole ratio are highly desirable for realizing high‐performance organic light‐emitting diodes (OLEDs). However, achieving this goal remains a formidable challenge due to the stringent molecular design principles involved. Herein, three highly efficient TADF materials based on lactam‐type electron‐acceptors are reported. The inherent rigidity and planar structure of lactam units, along with the ordered molecular arrangement in solid states, contribute to the reduction of nonradiative decay and the high horizontal transition dipole ratio in the optimized TADF emitters. Moreover, through precise control of the alignment of the lowest excited states by adjusting the charge transfer strength, the rate constants for reverse intersystem crossing (kRISC) are dramatically boosted. Consequently, the two optimized emitters exhibit outstanding merits of ultra‐high PLQYs (98% and 99%), high horizontal transition dipole ratios (91% and 87%), and fast RISC (kRISC ≈ 1.7 × 106 s−1). Thanks to these merits, the doped OLEDs achieve excellent performance. The top‐performing device achieve a maximum external quantum efficiency of 34.3%, a peak luminance of 57376 cd m−2, and small efficiency roll‐off.
Novel lactam electron‐acceptors are utilized to construct high‐performance TADF molecules. The rigid molecular skeletons, ordered molecular arrangements, and precise control of excited states contribute to achieving ultra‐high PLQYs (98%−99%), high horizontal dipole ratios (87%−91%), and rapid RISC (kRISC ≈ 1.7 × 106 s−1) simultaneously. The optimized OLEDs attain high EQEs of up to 34.3%, accompanied by ultra‐high luminances and small efficiency roll‐offs.
Pd modified ZnIn2S4/P25 (Pd@ZnIn2S4/P25) heterostructures have been synthesized by hydrothermal and photo-reduction method. The H2 evolution rate of optimal photocatalyst 0.5%Pd modified ...5ZnIn2S4/2P25 (0.5%Pd@5ZnIn2S4/2P25) are approximately 9100 and 3693 μmol·g-1h−1 under simulated sunlight and visible light irradiation with ethanol as the sacrificial agent, which are nearly 9 and 460 times higher than pure ZnIn2S4 and P25, respectively. The promoted photocatalytic performance can be attributed to the physicochemical properties of the catalysts and the strong electronic interaction between Pd modified ZnIn2S4 (Pd@ZnIn2S4) and P25, the improved transfer rate of photo-generated electrons and holes, the inhibited recombination of charge carriers, and the enhanced light harvesting. The results of photo-electrochemistry and EPR indicate that it is a Z-scheme photocatalytic system, in which the electrons accumulate on the conduct band of ZnIn2S4 and the holes assemble on the valence band of P25. This work provides an effective method to construct highly efficient photocatalytic systems for solar H2 generation.
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•Z-scheme Pd@ZnIn2S4/P25 photocatalytic system has been obtained by the hydrothermal combining photo-reduction method for the first time.•Pd@ZnIn2S4/P25 shows significantly enhanced hydrogen evolution performance compared with ZnIn2S4 and ZnIn2S4/P25.•The possible mechanisms of photocatalytic hydrogen evolution are proposed.
Pd modified ZnIn2S4/P25 (Pd@ZnIn2S4/P25) heterostructures have been synthesized by hydrothermal and photo-reduction method. The H2 evolution rate of optimal photocatalyst 0.5 %Pd modified 5ZnIn2S4/2P25 (0.5 %Pd@5ZnIn2S4/2P25) are approximately 9100 and 3693 μmol · g−1h−1 under simulated sunlight and visible light irradiation with ethanol as the sacrificial agent, which are nearly 9 and 460 times higher than pure ZnIn2S4 and P25, respectively. The promoted photocatalytic performance can be attributed to the physicochemical properties of the catalysts and the strong electronic interaction between Pd modified ZnIn2S4 (Pd@ZnIn2S4) and P25, the improved transfer rate of photo-generated electrons and holes, the inhibited recombination of charge carriers, and the enhanced light harvesting. The results of photo-electrochemistry and EPR indicate that it is a Z-scheme photocatalytic system, in which the electrons accumulate on the conduct band of ZnIn2S4 and the holes assemble on the valence band of P25. This work provides an effective method to construct highly efficient photocatalytic systems for solar H2 generation.
Lithium–sulfur batteries (LSBs) are promising candidates for next-generation high-performance batteries due to their high energy density, low cost, and environmental friendliness. However, issues ...such as low active material utilization, volume expansion, and serious shuttle effect have severely restricted their practical application. Herein, two 3D covalent organic frameworks (COFs), TFPB-TAA and TFPB-TAB with pto topology, are synthesized and applied as cathodes materials in LSBs. The abundant porosity in the 3D pto structure helps inhibit the shuttle effect and enables uniform sulfur distribution. Density functional theory calculations predict their strong polysulfide adsorption capacity. Impressive initial capacities of 1288 mA h/g for TFPB-TAA and 1192 mA h/g for TFPB-TAB are achieved at 0.1C along with exceptional capacity retentions of 69.3 and 73.5% at 0.5C after 400 cycles. This work provides new insights into the design of 3D COFs for advanced LSBs.
