Emerging Trends in Electron Transport Layer Development for Stable and Efficient Perovskite Solar Cells.

Perovskite solar cells (PSCs) stand at the forefront of photovoltaic research, with current efficiencies surpassing 26.1%. This review critically examines the role of electron transport materials (ETMs) in enhancing the performance and longevity of PSCs. It presents an integrated overview of recent advancements in ETMs, like TiO2, ZnO, SnO2, fullerenes, non-fullerene polymers, and small molecules. Critical challenges are regulated grain structure, defect passivation techniques, energy level alignment, and interfacial engineering. Furthermore, the review highlights innovative materials that promise to redefine charge transport in PSCs. A detailed comparison of state-of-the-art ETMs elucidates their effectiveness in different perovskite systems. This review endeavors to inform the strategic enhancement and development of n-type electron transport layers (ETLs), delineating a pathway toward the realization of PSCs with superior efficiency and stability for potential commercial deployment.

Physical simulation study on grouting water plugging of flexible isolation layer in coal seam mining.

Deep coal seam mining often leads to water resource loss due to bedrock water entering the workings of the mine and is discharged adjacent to the mining area. Using the geological conditions of the Maiduoshan coal mine, this paper applied a physical simulation experiment. The specified rock above the coal seam was hydraulically fractured in advance to form a postmining grouted fracture network, followed by grouting to construct a flexible isolation layer that blocked the infiltration of groundwater from the aquifer into the water-conducting fracture zone. Stress sensors, flow sensors and strata displacement monitoring technology were deployed inside the experimental material to study the spatial distribution characteristics and evolution law of the water-conducting fracture zone in the overlying rocks. Analysis of the water-conducting fracture zone development law, stress variation, overburden evolution characteristics, fracturing and grouting sequence of the flexible isolation layer and the effect of postmining grouting on the water barrier was conducted. These experiments verified the feasibility of fracture and grouting of the flexible isolation layer. These research results will provide practical guidance for the transition from the current safe and efficient mining methods to safe and green mining methods of deep coal mining in the western mining areas of China.

Quantitative study of electron tunneling dynamics in asymmetric coupled InGaN/GaN quantum wells.

Electron tunneling dynamics in asymmetric coupled triple InGaN/GaN quantum wells (ACQWs) with different well thicknesses of 3.0 nm (QW1), 2.5 nm (QW2), and 2.0 nm (QW3) were quantitatively investigated based on the time- and spectrally-resolved photoluminescence (PL) measurements and the rate-equation theory. Under weak excitation, only the emission peak of the widest well was observed at room temperature due to the effective electron tunneling from a wide to a narrow well, while all three emission peaks of the distinct wells were obtained at a high excitation level. The PL-intensity ratios of the wells in the initial transient spectra differed from those in the time-integrated spectra. With a set of rate equations and the experimental results of PL ratios and decay times, a 2 ns tunneling time from QW2 to QW1 was extracted and was decreased to 0.5 ns with increasing excitation, while the one from QW3 to QW2 was extracted to be ∼170ps. The extracted tunneling times are in good qualitative agreement with the data from the exponential fitting of the PL decay traces, which can be interpreted by the energy mismatches between relevant energy levels in the ACQWs. These results provide not only a better understanding of the carrier recombination and tunneling processes in the ACQW systems but also a useful guidance for high-performance ACQW-based optoelectronic and functional devices.

Catalytic pyrolysis characteristics of scrap printed circuit boards by TG-FTIR.

In the present work, pyrolysis and catalytic pyrolysis of waste printed circuit boards (WPCBs) was carried out in the coupling of Thermo Gravimetric Analysis and Fourier Transform Infrared Spectroscopy (TG-FTIR) under nitrogen atmosphere. The reaction temperature was increased from 30 to 700°C, while the heating rates were varied from 10 to 40°C/min. Experimental results show that the effect of catalyst on the WPCBs particles pyrolysis was significance. Compared with another two combustion-supporting agents (MgO, CaO), the whole pyrolysis process was optimized when the catalyst ZSM-5 was added into the WPCBs particles. The distributed activation energy model (DAEM) was used to analyze the kinetic parameters of the WPCBs pyrolysis. It was found that values of frequency factor (k0) changed with different activation energy (E) values during pyrolysis process. The activation energy values range from 129.15 to 280.53kJ/mol, and the frequency factor values range from 9.02×1010 to 4.21×1022s-1. The generated major products for the catalytic pyrolysis of WPCBs were H2, CO2, CO, H2O, phenols and aromatics.

Investigating the permeability of fractured rock masses and the origin of water in a mine tunnel in Shandong Province, China.

The coastal Sanshandao mine is threatened by the overlying Quaternary water and seawater. Following an introduction to the geology and hydrogeological conditions in the mine area, a detailed hydrogeological survey and sampling were conducted and hydrochemical and stable isotopic (δ2H and δ18O) tests on various waters were carried out to characterize the origin of water in the mine tunnels. Investigation and statistical analysis indicated that the northwest-trending fractures with large dip angles and long trace lengths are well developed in the northeast compared with those in the southwest of the mine. The permeability coefficients of the rock masses are in the range 4.19×10(-8)-2.25×10(-5) m/s, indicating that the fractured rock masses have generally low permeability. The seepage water had higher values of EC, total dissolved solids, and concentrations of most elements than the seawater and saline groundwater. Besides, the isotope composition of the waters indicated that the seepage water was more isotopically enriched than seawater but less than brine. The proportions of the three different sources were calculated based on hydrochemical and isotopic analyses. Overall, the mine water was composed of 72% seawater, 14.8% brine, and 13.2% atmospheric precipitation, respectively. Therefore, some preventive measures are essential to avoid the probability of seawater inrush.