Elimination of Intragrain Defect to Enhance the Performance of FAPbI3 Perovskite Solar Cells by Ionic Liquid.

Ionic liquids have been widely used to improve the efficiency and stability of perovskite solar cells (PSCs), and are generally believed to passivate defects on the grain boundaries of perovskites. However, few studies have focused on the relevant effects of ionic liquids on intragrain defects in perovskites which have been shown to be critical for the performance of PSCs. In this work, the effect of ionic liquid 1-hexyl-3-methylimidazolium iodide (HMII) on intragrain defects of formamidinium lead iodide (FAPbI3) perovskite is investigated. Abundant {111}c intragrain planar defects in pure FAPbI3 grains are found to be significantly reduced by the addition of the ionic liquid HMII, shown by using ultra-low-dose selected area electron diffraction. As a result, longer charge carrier lifetimes, higher photoluminescence quantum yield, better charge carrier transport properties, lower Urbach energy, and current-voltage hysteresis are achieved, and the champion power conversion efficiency of 24.09% is demonstrated. These observations suggest that ionic liquids significantly improve device performance resulting from the elimination of {111}c intragrain planar defects.

[Research progress of lower extremity alignment in total knee arthroplasty].

Knee osteoarthritis has become one of the common diseases of the elderly, total knee arthroplasty （TKA） is the most effective treatment for end-stage knee osteoarthritis at present. In TKA, the effective restoration of the lower extremity alignment is one of the key factors for the success of the operation, which greatly affects the postoperative clinical effect and prosthesis survival rate of patients. Mechanical alignment is a TKA alignment method which is first proposed, recognized and widely used in TKA. In recent years, with the in-depth research on the lower limb alignment and the rapid development of computer technology, the alignment technology in TKA has realized the transformation from "unified" to "individualized", two-dimensional to three-dimensional. New alignment methods, such as adjusted mechanical alignment, anatomic alignment, kinematic alignment, inverse kinematic alignment, restricted kinematic alignment and functional alignment have been proposed to provide surgeons with more choices. However, there is no conclusion on which alignment method is the best choice. This paper summarizes the current research status, advantages and disadvantages of various alignment methods in TKA, and aims to provide some reference for the selection of alignment methods in TKA.

Hierarchical zeolites containing embedded Cd0.2Zn0.8S as a photocatalyst for hydrogen production from seawater.

Uncovering an efficient and stable photocatalytic system for seawater splitting is a highly desirable but challenging goal. Herein, Cd0.2Zn0.8S@Silicalite-1 (CZS@S-1) composites, in which CZS is embedded in the hierarchical zeolite S-1, were prepared and show remarkably high activity, stability and salt resistance in seawater.