2,2′‐(perfluoronaphthalene‐2,6‐diylidene)dimalononitrile (F6‐TCNNQ) is investigated as a molecular p‐type dopant in two hole‐transport materials, ...2,2′,7,7′‐tetrakis(N,N‐diphenylamino)‐9,9‐spirobifluorene (Spiro‐TAD) and tris(4‐carbazoyl‐9‐ylphenyl)amine (TCTA). The electron affinity of F6‐TCNNQ is determined to be 5.60 eV, one of the strongest organic molecular oxidizing agents used to date in organic electronics. p‐Doping is found to be effective in Spiro‐TAD (ionization energy = 5.46 eV) but not in TCTA (ionization energy = 5.85 eV). Optical absorption measurements demonstrate that charge transfer is the predominant doping mechanism in Spiro‐TAD:F6‐TCNNQ. The host–dopant interaction also leads to a significant alteration of the host film morphology. Finally, transport measurements done on Spiro‐TAD:F6‐TCNNQ as a function of dopant concentration and temperature, and using a highly doped contact layer to ensure negligible hole injection barrier, lead to an accurate measurement of the film conductivity and hole‐hopping activation energy.
2,2′‐(perfluoronaphthalene‐2,6‐diylidene)dimalononitrile (F6‐TCNNQ) is investigated as p‐dopant in two hole‐transport materials (HTMs). Ultrathin, heavily doped 2,2′,7,7′‐tetrakis(N,N‐diphenylamino)‐9,9‐spirobifluorene (Spiro‐TAD) injection layers are implemented to ensure a negligible hole injection barrier in transport measurements, allowing accurate determination of conductivity and carrier hopping activation energy in HTMs such as Spiro‐TAD.
Abstract
Ambient sunlight-driven CO
2
methanation cannot be realized due to the temperature being less than 80 °C upon irradiation with dispersed solar energy. In this work, a selective light ...absorber was used to construct a photothermal system to generate a high temperature (up to 288 °C) under weak solar irradiation (1 kW m
−2
), and this temperature is three times higher than that in traditional photothermal catalysis systems. Moreover, ultrathin amorphous Y
2
O
3
nanosheets with confined single nickel atoms (SA Ni/Y
2
O
3
) were synthesized, and they exhibited superior CO
2
methanation activity. As a result, 80% CO
2
conversion efficiency and a CH
4
production rate of 7.5 L m
−2
h
−1
were achieved through SA Ni/Y
2
O
3
under solar irradiation (from 0.52 to 0.7 kW m
−2
) when assisted by a selective light absorber, demonstrating that this system can serve as a platform for directly harnessing dispersed solar energy to convert CO
2
to valuable chemicals.
With the country's strong support for infrastructure, tunnel-related projects are also increasing daily. Combined with the current Internet of Things (IoT) technology booming, the realization of ...intelligent construction has become the mainstream direction of today's tunnel construction. This design is mainly realized by combining IOT communication technology, sensor technology, and microcontroller technology. STM32 microcontroller acts as the system's central processing unit and receives real-time information on gas concentration, smoke concentration, pipe wall pressure, and water level collected by various sensors, then displays the data on the LED display after data processing. When the environmental data exceeds the standard, it will automatically drive and adjust the water pumps and fans and simultaneously move the WiFi module to remotely send the data to the mobile phone APP through the Internet cloud server. When the environmental data exceeds the standard, it automatically drives and adjusts the water pump and fan while moving the WiFi module to remotely send the data to the cell phone APP through the Internet cloud server. After actual testing, the system can meet the design requirements and further improve the safety and convenience of tunnel construction.
Bark is the traditional medicinal component of Eucommia ulmoides Oliver (E. ulmoides). However, the demand for E. ulmoides medicinal materials seriously limits their sustainability. To alleviate ...resource constraints, the bioactivity of E. ulmoides leaves and its pharmacodynamic basis were investigated. In the present study, extracts of E. ulmoides leaves were found to display potential renal protective properties in rat glomerular mesangial (HBZY-1) cells treated with high levels of glucose, suggesting that they possess potential factors capable of treating diabetic nephropathy. Ultra-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was used to comprehensively characterize the chemical components of E. ulmoides leaves. A total of 83 possible chemical components, including 12 iridoids, 13 flavonoids, 14 lignans, 20 phenylpropanoids, 14 phenolic acids, and 10 additional components, were identified in E. ulmoides leaves. Network pharmacology was used for a preliminary exploration of the potential mechanism of action of renal protection afforded by E. ulmoides leaves towards diabetic nephropathy. The network pharmacology results were verified using a series of biological experiments. The present study provided the basis for the comprehensive development and utilization of E. ulmoides leaves and the discovery of potential drugs.
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•In total 83 compounds were identified in an alcohol extract of E. ulmoides leaves.•A feasible compound-target-pathway network pharmacology model was established.•The potential core active compounds, targets, and pathways were screened.•Biological research verified the results of network pharmacology.
Solar-heating catalysis has the potential to realize zero artificial energy consumption, which is restricted by the low ambient solar heating temperatures of photothermal materials. Here, we propose ...the concept of using heterostructures of black photothermal materials (such as Bi
Te
) and infrared insulating materials (Cu) to elevate solar heating temperatures. Consequently, the heterostructure of Bi
Te
and Cu (Bi
Te
/Cu) increases the 1 sun-heating temperature of Bi
Te
from 93 °C to 317 °C by achieving the synergy of 89% solar absorption and 5% infrared radiation. This strategy is applicable for various black photothermal materials to raise the 1 sun-heating temperatures of Ti
O
, Cu
Se, and Cu
S to 295 °C, 271 °C, and 248 °C, respectively. The Bi
Te
/Cu-based device is able to heat CuO
/ZnO/Al
O
nanosheets to 305 °C under 1 sun irradiation, and this system shows a 1 sun-driven hydrogen production rate of 310 mmol g
h
from methanol and water, at least 6 times greater than that of all solar-driven systems to date, with 30.1% solar-to-hydrogen efficiency and 20-day operating stability. Furthermore, this system is enlarged to 6 m
to generate 23.27 m
/day of hydrogen under outdoor sunlight irradiation in the spring, revealing its potential for industrial manufacture.
Ultra-wideband spoof surface plasmon polaritons (SSPPs) based on compact balanced coplanar stripline (CPS) waveguides are proposed. Compared with the conventional CPS-based terahertz (THz) SSPP unit ...cell, the proposed one has achieved a size reduction of 55.2% under the condition of the same asymptotic frequency. The propagation and attenuation characteristics of the proposed SSPP waveguide can be easily manipulated by adjusting the geometry dimensions of the SSPP unit cell. It indicates that the cut-off frequency of the SSPP waveguide has its tunable flexibility thereby facilitating the filter design. To further validate the proposed idea, a similar topology in microwave regime is designed and measured, where the microwave feeding can be easily realized by embedding a balun structure from unbalanced microstrip line to balanced CPS. The measurement of the microwave filter prototype illustrates ultra-wideband bandpass filtering characteristics with return losses of over 10 dB and average insertion losses of 3.2 dB in the passband of 1.9-14 GHz. The presented work may have significant potentials to develop the miniaturization of various planar plasmonic devices and integrated circuits in microwave and THz regimes.
A compact seventh-order wideband bandpass filter (BPF) with sharp roll-off skirts using coupled lines and open stubs (OSs)/shorted stubs (SSs) is proposed. Seven transmission poles in the passband ...and four deep transmission zeros from 0 to 2f0 (f0 denotes centre frequency of the passband) can be realised with the help of half-wavelength OSs and quarter-wavelength SSs. For demonstration, a wideband BPF prototype is designed, fabricated with a measured 3-dB fractional bandwidth of 78% (1.22–2.77 GHz) and transition band roll-off rates of over 175 dB/GHz. Good agreement between the simulations and measurements validates the design method.
Insomnia and the inability to sleep affect people's health and well-being. However, its systematic estimates of prevalence and distribution in the general population in China are still lacking. A ...population-based cluster sampling survey was conducted in the rural and urban areas of Hunan, China. Subjects (n = 26,851) were sampled from the general population, with a follow-up using the Pittsburgh Sleep Quality Index (PSQI) for interview to assess quality of sleep and Insomnia (PSQI score >5). While the overall prevalence of insomnia was 26.6%, and little difference was found between males (26.3%) and females (27.0%); the mean PSQI score was 4.26 (±2.67), and significant higher in females (4.32 ± 2.70) than males (4.21 ± 2.64, p = 0.003). Individuals in the rural areas tended to report a higher PSQI score (4.45 ± 2.81) than urban residents did (4.18 ± 2.60) (p < 0.001) and the estimates of prevalence of insomnia was 29.4% in the rural areas, significant higher than 25.5% in the urban areas (p < 0.001). Multiple logistic regression analysis showed that female gender, older age, higher level of education, being unmarried, living in the rural area, cigarette smoking and alcohol drinking were associated with insomnia. Our study may provide important information for general and mental health research.
In this essay, a case study is presented on the electronic structure of several metal halide perovskites (MHP) using Kelvin probe (KP)‐based surface photovoltage (SPV) measurements and ultraviolet ...photoemission spectroscopy (UPS) to demonstrate the advantages, but also the pitfalls, of using these techniques to characterize the surfaces of these materials. The first part addresses the loss of halide species from perovskite surfaces upon supragap illumination in vacuum. This has the potential to cause both a long‐term alteration of the sample work function and a modification of the KP tip during SPV measurements. If undetected, this leads to a misinterpretation of the MHP surface potential. The second part illustrates the difficulties in determining the valence band maximum (VBM) of MHP surfaces with UPS and stresses the importance of taking into account the low density of states at the VBM edge. Given this circumstance, specific care must be taken to eliminate measurement artifacts in order to ascertain the presence or absence of low densities of electronic gap states above the VBM. This essay also highlights issues such as film degradation, nonequilibrium situations (e.g., SPV), and satellite emissions, which occur during photoemission spectroscopy.
This article puts in perspective the advantages of two techniques applied to metal halide perovskite surfaces, i.e., photoemission spectroscopy and Kelvin probe contact potential measurements, as well as the difficulties stemming from light‐induced degradation and loss of halide species in vacuum, and low density of states at the valence band maximum of these materials.
Understanding the origin and distribution of electronic gap states in metal halide perovskite (MHP) thin films is crucial to the further improvement of the efficiency and long‐term stability of ...MHP‐based optoelectronic devices. In this work, the impact of Lewis‐basic additives introduced in the precursor solution on the density of states in the perovskite bandgap is investigated. Ultraviolet photoemission spectroscopy and contact potential difference measurements are conducted on MHP thin films processed from dimethylformamide (DMF)‐based solutions to which either no additive, dimethylsulfoxide (DMSO), or N‐methylpyrrolidine‐2‐thione (NMPT) is added. The results show the presence of a density of states in the gap of methylammonium lead halide films processed from DMSO‐containing solution. The density of gap states is either suppressed when the methylammonium concentration in mixed cation films is reduced or when NMPT is used as an additive, and eliminated when methylammonium (MA) is replaced with cesium or formamidinium (FA). These results are consistent with the notion that reaction products that result from DMSO reacting with MA+ in the precursor solution are responsible for the formation of gap states.
Minimization of the gap states in halide perovskites is crucial for approaching the theoretical device limit. This work correlates the appearance of gap states in methylammonium lead halides and the presence of dimethylsulfoxide in the processing solution. The results suggest the link between the products of the dimethylsulfoxide–methylammonium reaction and the gap states. Replacement with a non‐reactive additive eliminates these gap states.
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