Nanocoating combines the protective properties of conventional coating system with effects on nanoscale such as high hardness, UV scattering, and uniform dispersing. Their facile and low-cost synthesis, together with superior protective properties and multi-functionalities, makes nanocoating attractive candidates for next-generation coating systems. In this review, a brief introduction regarding mainstream nanocoating and its related challenges including the zinc oxide-, titanium dioxide-, silica dioxide-, graphene-, carbon nanotube-based nanocoating system is presented. Finally, a perspective of the nanocoating is demonstrated.

Simple N-phenylcarbazole (NPC) could readily form brightly mechanofluorescent crystals with mechanically touch-sensitive response, regardless of crystallization methods. NPC with room-temperature photophosphorescence did not exhibit mechano-phosphorescence, signifying that the excitation modes could play an important role in affecting light-emitting processes.

Bright NUV mechanofluorescence from a terpyridine-based pure organic crystal with non-centrosymmetric packing and a piezoelectric space group.

Multicolor mechanoluminescence (ML) was first realized by using the stable organic blue ML emitter N-phenylcarbazole as the host matrix. It is claimed that a good ML host should have a moderate melting point and be able to dissolve or disperse organic dyes but maintain high ML activity and crystallinity. This strategy is versatile and can avoid difficult molecular design and troublesome chemical synthesis.

Colloidal halide perovskite nanocrystals are promising candidates for next-generation optoelectronics because of their facile synthesis and their outstanding and size-tunable properties. However, these materials suffer from rapid degradation, similarly to their bulk perovskite counterparts. Here, we survey the most recent strategies to boost perovskite nanocrystals stability, with a special focus on the intrinsic chemical- and compositional-factors at synthetic and post-synthetic stage. Finally, we review the most promising approaches to address the environmental extrinsic stability of perovskite nanocrystals (PNCs). Our final goal is to outline the most promising research directions to enhance PNCs’ lifetime, bringing them a step closer to their commercialization.

Owing to academic significance and potential applications, mechanofluorochromism has attracted much research interest. However, among the hundreds of mechanofluorochromic organic and metallorganic compounds reported to date, those with high contrast, multicolour and multichannel switching, and a remarkable mechanohypsochromic luminescence are rarely realized. This paper presents the synthesis and unusual mechano- and thermo-chromic fluorescence behaviours of a new 1,4-diketo-pyrrolo[3,4-c]pyrrole derivative (CODPP) with oxadiazole as the conjugation bridge and carbazole as the end donor. The as-prepared crystalline CODPP emits a near-infrared light (723 nm, NIR state) and can be mechanically ground into a red emitting state (614 nm, R state), rendering a large mechanofluorohypsochromic shift up to 110 nm. However, unlike most mechanofluorochromic materials, the ground R state could not revert to the pristine (NIR) state upon heat annealing; instead, a new yellow emitting state (557 nm, Y state) is formed, and grinding the Y state affords the R state. Moreover, both the Y and R states hardly change their colours upon solvent fuming but can form the NIR state only by recrystallization or reprecipitation. These changes are repeatable and are characterized and discussed based on IR, X-ray diffraction, DSC, and time-resolved fluorescence spectra. This remarkable mechano- and thermo-hypsochromic luminescence has enriched the types of stimuli responsive materials and enlarged the optical properties of DPP derivatives.