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A theoretical model for the calculation of thermal elastohydrodynamic lubrication performance of the flow distribution pair of piston pumps is established, which is composed of the oil film pressure governing equation and energy equation, and solved by means of numerical solution and simulation. We carry out quantitative analysis of the influence of various parameters on the thermal elastohydrodynamic lubrication characteristics of the flow distribution pair. The results indicate that both the oil film thickness and the cylinder tilt angle of the flow distribution pair vary in a periodic manner. The increase in the rotational speed of the cylinder block will increase the film thickness of the oil film and reduce the fluctuation, and the inclination angle of the cylinder block and its fluctuation amplitude will decrease. An increase in working pressure will lead to a decrease in the average oil film thickness, an increase in fluctuations, and an elevation in both the tilt angle of the cylinder block and its fluctuation amplitude. The increase in the rotational speed of the cylinder block and the increase in the working pressure will lead to the increase in the viscous friction dissipation of the flow distribution pair, the increase in the oil film temperature and the increase in the leakage. The reduction in the sealing belt will lead to the reduction in oil film friction torque and leakage. [ABSTRACT FROM AUTHOR]

The planar perovskite solar cells (PSCs) using TiO2 as the electron transport layer (ETL) are undergoing a stagnated efficiency improvement, which the inferior TiO2 ETL mainly limits. Herein, a flocculating‐regulated TiO2 deposition using SnCl2·2H2O is reported as the flocculate to control the nanoparticle size finely for optimizing TiO2 deposition and to achieve a synergistic Sn doping. The SnCl2·2H2O incorporated into bath precursor can bridge‐link the suspended nanoparticles, which promotes the precipitation of large‐sized nanoparticles and leaves the smaller‐sized nanoparticles for deposition, leading to a compact TiO2 film with marked reduced surface roughness. Meanwhile, along with flocculating‐regulated TiO2 deposition, it can also be achieved the Sn‐doping of TiO2, which increases the conductivity of TiO2 thin films by ≈2.5 times. As a consequence, attributing to the optimized interface contact and accelerated interfacial electron transport, the planar PSCs achieved a certification efficiency of 25.85%, the highest value among the TiO2‐based planar PSCs to date. In addition, the PSCs can maintain 99% of their initial efficiency after more than 4500 h of storage in ambient air, showing excellent stability. [ABSTRACT FROM AUTHOR]

Ion migration is a major issue hindering the long‐term stability of perovskite solar cells (PSCs). As an intrinsic characteristic of metal halide perovskite materials, ion migration is closely related to the atomic arrangement and coordination, which are the basic characteristic differences among various facets. Herein, we report the facet‐related ion migration, and then achieve the inhibition of ion migration in perovskite through finely modulating the facet orientation. We show that the (100) facet is substantially more vulnerable to cationic migration than the (111) facet. The main reason for this difference in migration is that the cationic migration route in the (111) facet deviates from that in the (100) facet, which increases the active migration energy and weakens the contribution from the electric field during operation. We prepare a (111)‐dominated perovskite film by incorporating a facile and green addition of water (H2O) into the antisolvent, further achieving a power conversion efficiency (PCE) of 26.0 % (25.4 % certification) on regular planar PSCs and 25.8 % on inverted PSCs. Moreover, the unencapsulated PSCs can maintain 95 % of their initial PCE after 3500‐hours operation under simulated AM1.5 illumination at the maximum power point. [ABSTRACT FROM AUTHOR]