The pioneering exfoliation of monolayer tungsten diselenide has greatly inspired researchers toward semiconducting applications. WSe2 belongs to a family of transition‐metal dichalcogenides. Similar to graphene, WSe2 and analogous dichalcogenides have layered structures with weak van der Waals interactions between two adjacent layers. First, the readers are presented with the fundamentals of WSe2, such as types, morphologies, and properties. Here, we report the characterization principles and practices such as microscopy, spectroscopy, and diffraction. Second, the methods for obtaining high‐quality WSe2, such as exfoliation, hydrothermal and chemical vapor deposition, are briefly listed. With advantages of light weight, flexibility, and high quantum efficiency, 2D materials may have a niche in optoelectronics as building blocks in p‐n junctions. Therefore, we introduce a state‐of‐the‐art demonstration of heterostructure devices employing the p‐type WSe2 semiconductor. The device architectures include field‐effect transistors, photodetectors, gas sensors, and photovoltaic solar cells. Due to its unique electronic, optical, and energy band properties, WSe2 has been increasingly investigated due to the conductivity of the p‐type charge carrier upon palladium contact. Eventually, the dynamic research on WSe2 and van der Waals heterostructures is summarized to arouse the passion of the 2D research community.image

Silicon is employed in a variety of electronic and optical devices such as integrated circuits, photovoltaics, sensors, and detectors. In this paper, Au-assisted etching of silicon has been used to prepare superhydrophobic surfaces that may add unique properties to such devices. Surfaces were characterized by contact angle and contact angle hysteresis. Superhydrophobic surfaces with reduced hysteresis were prepared by Au-assisted etching of pyramid-structured silicon surfaces to generate hierarchical surfaces. Consideration of the Laplace pressure on hydrophobized hierarchical surfaces gives insight into the manner by which contact is established at the liquid/composite surface interface. Light reflectivity from the etched surfaces was also investigated to assess application of these structures to photovoltaic devices.

Two light‐driven chiral fluorescent molecular switches, (R,S,R)‐switch 1 and (R,S,R)‐switch 2, are prepared by means of hydrogen‐bonded (H‐bonded) assembly of a photoresponsive (S) chiral fluorescent molecule, respectively with a cyano substitution at different positions as an H‐bond acceptor and an opposite (R) chiral molecule as an H‐bond donor. The resulting two switches exhibit tunable and reversible Z/E photoisomerization irradiated with 450 nm blue and 365 nm UV light. When doped into an achiral liquid crystal, both switches are found to be able to form a CPL tunable luminescent helical superstructure. In contrast to the tunable CPL characteristics of the system incorporating switch 2, exposure of the system incorporating switch 1 to 365 nm and 450 nm radiation can lead to controllable different photostationary CPL behavior, including switching‐off and polarization inversion. In addition, optical information coding is demonstrated using the system containing switch 1.

Dissipative self-assembly, one of fundamentally important out-of-equilibrium self-assembly systems, can serve as a controllable platform to exhibit temporal processes for various non-stimulus responsive properties. However, construction of light-fueled dissipative self-assembly structures with transformable morphology to modulate non-photoresponsive properties remains a great challenge. Here, we report a light-activated photodeformable dissipative self-assembly system in aqueous solution as metastable fluorescent palette. Zwitterionic sulfonato-merocyanine is employed as a light-induced amphiphile to co-assemble with polyethyleneimine after light irradiation. The formed spherical nanoparticles spontaneously transform into cuboid ones in the dark with simultaneous variation of the particle sizes. Then the two kinds of nanoparticles can reversibly interconvert to each other by periodical light irradiation and thermal relaxation. Furthermore, after loading different fluorophores exhibiting red, green, blue emissions and their mixtures, all these fluorescent dissipative deformable nanoparticles display time-dependent fluorescence variation with wide range of colors. Owing to the excellent performance of photodeformable dissipative assembly platform, the light-controlled fluorescence has achieved a 358-fold enhancement. Therefore, exposing the nanoparticles loaded with fluorophores to light in a spatially controlled manner allows us to draw multicolored fluorescent images that spontaneously disappeared after a specific period of time.

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