Activating Halogen Circulation Enables Efficient and Stable Wide-Bandgap Mixed-Halide Perovskite Solar Cells.

Developing strategies to manage ion-migration-induced phase segregation in wide-bandgap (WBG) perovskites is crucial for achieving high-performance perovskite-silicon tandem solar cells (TSCs). However, maintaining continuous suppression of phase segregation from the film crystallization process to device operation remains a significant challenge. The present study demonstrates an efficient strategy of activating halogen circulation in WBG perovskite by using halogen circulation agents (HCA) of N-halosuccinimide molecules as the sustainable stabilizers, in order to achieve dynamic halogen equilibrium within the precursor solution and perovskite film, which blocks the migration path of Br/I ions both in crystallization and aging of WBG perovskites.

Conformal Imidazolium 1D Perovskite Capping Layer Stabilized 3D Perovskite Films for Efficient Solar Modules.

Although the perovskite solar cells have been developed rapidly, the industrialization of perovskite photovoltaics is still facing challenges, especially considering their stability issues. Here, the new type of benzimidazolium salt, N,N'-dialkylbenzimidazolium iodide, is proposed and functionalized to convert the three-dimensional (3D) FACs-perovskite films into one-dimensional (1D) capping layer topped 1D/3D structure either in individual device or module levels. This conformal interface modulation demonstrates that not only can effectively stabilize FACs-based perovskite films by inhibiting the lateral and vertical iodide diffusions in devices or modules, ensuring an excellent operation and environmental stability, but also provides an excellent charge transporting channel through the well-designed 1D crystal structure.

Sulfonate-Assisted Surface Iodide Management for High-Performance Perovskite Solar Cells and Modules.

Owing to the ionic nature of lead halide perovskites, their halide-terminated surface is unstable under light-, thermal-, moisture-, or electric-field-driven stresses, resulting in the formation of unfavorable surface defects. As a result, nonradiative recombination generally occurs on perovskite films and deteriorates the efficiency, stability, and hysteresis performances of perovskite solar cells (PSCs). Here, a surface iodide management strategy was developed through the use of cesium sulfonate to stabilize the perovskite surface.

Perovskite Quantum Dots as Multifunctional Interlayers in Perovskite Solar Cells with Dopant-Free Organic Hole Transporting Layers.

Perovskite solar cells (PSCs) with organic hole transporting layers (o-HTLs) have been widely studied due to their convenient solution processing, but it remains a big challenge to improve the hole mobilities of commercially available organic hole transporting materials without ion doping while maintaining the stability of PSCs. In this work, we demonstrated that the introduction of perovskite quantum dots (QDs) as interlayers between perovskite layers and dopant-free o-HTLs (P3HT, PTAA, Spiro-OMeTAD) resulted in a significantly enhanced performance of PSCs. The universal role of QDs in improving the efficiency and stability of PSCs was validated, exceeding that of lithium doping.

Automatic measurement of fetal Nuchal translucency from three-dimensional ultrasound data.

The Nuchal translucency (NT), which is the collection of fluid at the back of the fetal neck, is related to chromosomal defects and early cardiac failure in first trimester of pregnancy. In clinic, the thickness of NT is used as an important marker in prenatal screening, and is manually measured by sonographers in the mid-sagittal plane. In this paper, an automatic method based on dynamic programming is proposed to detect the thickness and area of NT in the mid-sagittal plane.

Automatic Detection of Standard Sagittal Plane in the First Trimester of Pregnancy Using 3-D Ultrasound Data.

Fetal nuchal translucency (NT) thickness is one of the most important parameters in prenatal screening. Locating the mid-sagittal plane is one of the key points to measure NT. In this paper, an automatic method for the sagittal plane detection using 3-D ultrasound data is proposed.

Automatic segmentation of a fetal echocardiogram using modified active appearance models and sparse representation.

A novel approach is presented to automatically segment the left ventricle in fetal echocardiograms. The proposed approach strategically integrates sparse representation, global constraint, and local refinement algorithms into an active appearance model (AAM) framework. In the training stage, we construct an enhanced AAM texture model to deal with the speckle and texture ambiguities.