Chao Li

All-polymer solar cells (all-PSCs) have shown good potential for achieving balanced power conversion efficiency (PCE) and operational stability. However, precise control of the morphology remains challenging. Here, we constructed a bulk p–i–n structure with a regulated i-region by incorporating a shamrock-shaped nonfullerene acceptor, AQI4. This ternary formulation resulted in optimized energy-level stairing, enhanced exciton dissociation, and reduced energy loss. In blended thin film fabrication, a binary solvent of chlorobenzene (CB):o-xylene (OXY) was used, which enhanced the crystallization of the polymers and formed a high-density fibril network. The i-region width was reduced to less than 2 nm. This structural refinement enabled efficient charge transport through tie-chains between polymer crystallizations, thereby suppressing charge recombination. As a result, the organic solar cell (OSC) devices achieved a PCE of 20.1% (certified as 19.5%) and retained good stability. The T80 lifetime of over 1800 h in the OSC structure was recorded. Notably, the binary solvent CB:OXY also contributed to a feasible printing fabrication; the 18.4 cm2 OSC mini-modules achieved a PCE of 16.5%. Our results suggest that the shape of the guest molecule may be a key point to modulate the bulk p–i–n structure and improve the performance of all-PSCs.

The parameters of soil hydraulic functions are essential to the accurate simulation of soil moisture based on the Richards equation. Optimal values of these parameters can be calibrated by inverse modeling, in which the incomplete consideration of various errors may influence the parameter estimation results, thus further limiting the accuracy of modeling and forecasting. The ensemble Kalman filter (EnKF) is believed to be a flexible and effective sequential data assimilation method that provides a framework of explicit consideration of the various sources of uncertainty and is suitable for real‐time, updated observations. The objective of this study was to extend the use of the EnKF to parameter estimation in vadose zone hydrology to improve the treatment of uncertainty in the calibration process. The parameters of soil hydraulic functions were estimated by assimilating observations of soil water pressure dynamics using EnKF with an augmentation technique. The results of the synthetic experiments on 12 soils with different textures indicated that EnKF estimates can quickly approach stable estimates. In contrast to the batch calibration process that used a simple least squares objective function, the EnKF reduced the risk of obtaining suboptimal estimates. The EnKF also performed well in the multiparameter estimation scenarios with synthetic observations and in its application in a heterogeneous soil profile with in situ field observations from a previous study. We further explored the factors that may influence estimation results, including the initial estimate, the ensemble size, the observation error and the model error, the assimilation interval, the water regime, and the variability of the estimated parameters. The result of this study indicates that the EnKF scheme is an effective method for parameter estimation in vadose zone hydrology.

Froth flotation has been widely used in upgrading iron ores. Iron ore flotation can be performed in two technical routes: direct flotation of iron oxides and reverse flotation of gangue minerals with depression of iron oxides. Nowadays, reverse flotation is the most commonly used route in iron ore flotation. This review is focused on the reverse flotation of iron ores, consisting of reverse cationic flotation and reverse anionic flotation. It covers different types of collecting agents used in reverse iron ore flotation, the surface characteristics of minerals commonly present in iron ores (e.g., iron oxides, quartz, alumina-bearing minerals, phosphorus-bearing minerals, iron-bearing carbonates, and iron-bearing silicates), and the adsorption mechanisms of the collecting agents at the mineral surface. The implications of collecting agent–mineral interactions for improving iron ore flotation are discussed.