Frictional forces between self-assembled surfactant monolayers on mica and a silicon tip were measured under dynamic shear, using a lateral force microscope. Molecular friction was resolved on the surfactantcoated surfaces. Dependence of friction upon load and shear velocity was also studied. The results are compared with those for bare substrate mica under similar conditions. We found that at a fixed shear velocity, friction increases with applied load in a nearly linear fashion for both the substrate mica and the monolayer-coated surfaces. Within the velocity range of 0.01 to 120 pra/s, friction increases monotonically with shear velocity for bare mica; however, for the monolayer surfaces, friction initially increases with velocity and then decreases. Similar behavior was also found for monolayers in hexane-saturated atmosphere, but with the maximum friction occurring at a higher velocity than that in dry air.

Uniform colloidal Bi 2 S 3 nanodots and nanorods with different sizes have been prepared in a controllable manner via a hot injection method. X-ray diffraction (XRD) results show that the resulting nanocrystals have an orthorhombic structure. Both the diameter and length of the nanorods increase with increasing concentration of the precursors. All of the prepared Bi 2 S 3 nanostructures show high efficiency in the photodegradation of rhodamine B, especially in the case of small sized nanodots-which is possibly due to their high surface area. The dynamics of the photocatalysis is also discussed.

The plasmonic characteristic of core–shell nanomaterials can effectively improve exciton‐generation/dissociation and carrier‐transfer/collection. In this work, a new strategy based on core–shell Au@CdS nanospheres is introduced to passivate perovskite grain boundaries (GBs) and the perovskite/hole transport layer interface via an antisolvent process. These core–shell Au@CdS nanoparticles can trigger heterogeneous nucleation of the perovskite precursor for high‐quality perovskite films through the formation of the intermediate Au@CdS–PbI2 adduct, which can lower the valence band maximum of the 2,2,7,7‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)9,9‐spirobifluorene (Spiro‐OMeTAD) for a more favorable energy alignment with the perovskite material. With the help of the localized surface plasmon resonance effect of Au@CdS, holes can easily overcome the barrier at the perovskite/Spiro‐OMeTAD interface (or GBs) through the bridge of the intermediate Au@CdS–PbI2, avoiding the carrier accumulation, and suppress the carrier trap recombination at the Spiro‐OMeTAD/perovskite interface. Consequently, the Au@CdS‐based perovskite solar cell device achieves a high efficiency of over 21%, with excellent stability of ≈90% retention of initial power conversion efficiencies after 45 days storage in dry air.

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