It is an effective strategy to improve the performance of quasi-two-dimensional (Q-2D) perovskite solar cells (PSCs) by introducing fluoro-substituted aromatic alkylammonium spacer cations into the active layer. Herein, the influence of the benzylammonium (BA) and the x-fluorobenzylammonium (xFBA) cation, in which x stands for the substitution position of the benzene ring (o, ortho; m, meta; p, para), on the crystal orientation, phase distribution, film morphology of the Q-2D (n = 5) perovskite films, and the corresponding device performance is systematically evaluated. The result suggests that compared with BA and oFBA, mFBA and pFBA have a larger dipole moment, forming a dense perovskite film with gradient structures where the n = 1 2D perovskite mainly exists at the top of the film and the large n-phase perovskite exists at the bottom of the film. Encouragingly, the (pFBA)2MA4Pb5I16 (MA = CH3NH3 +)-based perovskite solar cells achieve the highest efficiency of 17.12%, with an open-circuit voltage of 1.175 V, a short-circuit current density of 18.50 mA cm–2, and a fill factor of 78.78%, which is significantly higher than those of BA (14.07%)-, oFBA (12.89%)-, and mFBA (14.67%)-based PSCs. Furthermore, pFBA-based devices also exhibit the best stability compared to the other three devices.

The implementation of high-performance membranes in large-scale CO 2 capture has the potential to significantly decrease the capture cost and reduce the environmental footprints. However, highly permeable polymers rarely have sufficient selectivity for energy-efficient carbon capture. In this study, zeolite imidazolate framework hollow nanoparticles (ZIF-HNPs) were synthesized and embedded into highly permeable polymers as versatile fillers to prepare mixed matrix membranes (MMMs). The interior hollow architecture minimizes transport resistance of gas diffusion through the fillers while its molecular-sieving shell provides high selectivity. With 28 vol% loading of ZIF-HNPs, the membrane exhibits CO 2 permeability of 7,128 Barrer and CO 2 /CH 4 selectivity of 16.4 (57.7% and 31.4% higher than these of pristine membrane), which surpass the upper bound of the state-of-the-art reported polymeric membranes. Meanwhile, we proposed a modified Maxwell model based on the hierarchical structure of the MMM to analyze the effects of cavity size and loading on gas transport behaviors within membranes.

BODIPY dyes have recently been used for photothermal and photodynamic therapy of tumors. However, complex multi-materials systems, multiple excitation wavelengths and the unclear relationship between BODPY structures and their PTT/PDT...

To take advantage of the respective strengths of aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) materials, in this paper a unique approach is taken which is that tetraphenylethene and triphenylamine (classical AIEs), borondipyrromethene and benzothiadiazole (classical ACQs) are selected to construct AIE@ACQ bimolecular systems by simple compounding method, focusing on the effects on optical properties such as fluorescence, photothermal therapy, phosphorescence, and photodynamic therapy. Above all, the mechanisms and laws of the system are preliminarily found. First, AIEs and ACQs must, respectively, have electron-acceptor and electron-donors to form an intermolecular push-pull structure to ensure that the two molecules are close to each other, and intermolecular 𝝅-𝝅 stacking interaction separates the highest occupied molecular orbitals and lowest unoccupied molecular orbitals to reduce 𝚫E st , causing intriguing optical properties. Second, the matching degree of the conjugate structure between AIEs and ACQs is also an important factor. Utilizing these systems, it is found that different structural compositions possess different optical synergy properties, so different AIE@ACQ bimolecular systems can be constructed according to the actual needs, which have the advantages of efficiency and convenience, providing a new idea for the united application of AIEs and ACQs.

Comparative analysis of interfacial electron injection and density of states was performed on a dye/TiO2 system with stoichiometric and defective surfaces.