Defects at the buried interface between the perovskite film and electron transport layer (ETL) are detrimental for both the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). Herein, phenylhydrazinium chloride (PC) is designed as an effective passivation agent to significantly reduce defect density at the buried interface. It is found that the strong interaction between PC and PbI₂ not only passivates defects at the buried interface, but also retards the crystallization process of perovskite films, enabling high-quality perovskite films with low defects, resulting in improved PCE from 24.67% to 25.80% for small area devices and PCE up to 24.12% for large-area (1 cm²) ones. Additionally, the PCE of the flexible PSC (F-PSC) was improved to 24.54%, and both are among the highest in their respective categories. The excellent stability of the PSCs was also achieved, with 93.94% of the initial PCE retained after 1008 hours at 25 °C under 30% humidity. This paves a way for buried modification of perovskite films, large-scale preparation of PSCs, and fabrication of F-PSCs.

Packaging is a food preservation technology widely used in the world. Naturally-sourced, biodegradable polymers are becoming increasingly popular in the food packaging sector. Packaging films prepared using cellulose as raw material would contribute to resource sustainability, but the difficulty of cellulose solubilization limits their further development. In view of this, a series of novel solvent systems (LiCl/DMAc, ILs, TBAH/DMSO, NMMO, alkali/urea solutions, metal-complex solutions) were used to prepare high-strength and high-performance cellulose-based films; their characteristics and the mechanisms involved were investigated. Composite films prepared by blending cellulose with various polymers (synthetic polymers, natural polymers, proteins and enzymes, metal particles, and plant phenols) and their functional properties were also investigated. Problems with cellulose-based films and the outlook for future research are discussed. It is hoped that in the near future high-performance, biodegradable and sustainably-produced cellulose-based films will lead the food packaging industry into a new era and further promote the sustainable use of resources.

Phospholipids and hyaluronan have been implied to fulfil important roles in synovial joint lubrication. Since both components are present in synovial fluid, self-assembly structures formed by them should also be present. We demonstrate by small angle X-ray scattering that hyaluronan associates with the outer shell of dipalmitoylphophatidylcholine (DPPC) vesicles in bulk solution. Further, we follow adsorption to silica from mixed hyaluronan/DPPC vesicle solution by Quartz Crystal Microbalance with Dissipation measurements. Atomic Force Microscope imaging visualises the adsorbed layer structure consisting of non-homogeneous phospholipid bilayer with hyaluronan/DPPC aggregates on top. The presence of these aggregates generates a long-range repulsive surface force as two such surfaces are brought together. However, the aggregates are easily deformed, partly rearranged into multilayer structures and partly removed from between the surfaces under high loads. These layers offer very low friction coefficient (<0.01), high load bearing capacity (≈23MPa), and self-healing ability. Surface bound DPPC/hyaluronan aggregates provide a means for accumulation of lubricating DPPC molecules on sliding surfaces.

Efficient lubricants should be able to build surface layers that result in low friction and high load bearing capacity. In this work we show how this can be achieved in aqueous media by means of adsorption of a diblock copolymer consisting of a cationic anchor block without side chains and an uncharged and hydrophilic bottle-brush block that protrudes into solution. Surface and friction forces were measured between negatively charged silica surfaces coated with adsorbed layers of the cationic diblock copolymer, utilizing the atomic force microscope colloidal probe technique. The interactions between the surfaces coated with this copolymer in water are purely repulsive, due to a combination of steric and electrostatic double-layer forces, and no hysteresis is observed between forces measured on approach and separation. Friction forces between the diblock copolymer layers are characterized by a low friction coefficient, μ ≈ 0.03–0.04. The layers remain intact under high load and shear due to the strong electrostatic anchoring, and no destruction of the layer was noted even under the highest pressure employed (about 50 MPa). Addition of NaCl to a concentration of 155 mM weakens the anchoring of the copolymer to the substrate surface, and as a result the friction force increases.

The bending energy of the lipid membrane is central to biological processes involving vesicles, such as endocytosis and exocytosis. To illustrate the role of bending energy in these processes, we study the response of single-component giant unilamellar vesicles (GUVs) subjected to external osmotic stress by glucose addition. For osmotic pressures exceeding 0.15 atm, an abrupt shape change from spherical to prolate occurs, showing that the osmotic pressure is balanced by the free energy of membrane bending. After equilibration, the external glucose solution was exchanged for pure water, yielding rapid formation of monodisperse daughter vesicles inside the GUVs through an endocytosis-like process. Our theoretical analysis shows that this process requires significant free energies stored in the deformed membrane to be kinetically allowed. The results indicate that bending energies stored in GUVs are much higher than previously implicated, with potential consequences for vesicle fusion/fission and the osmotic regulation in living cells.