Investigations of organic–inorganic metal halide perovskite materials have attracted extensive attention due to their excellent properties including bandgap tunability, long charge diffusion length, and outstanding optoelectronic merits. Organic–inorganic metal halide perovskites are demonstrated to be promising materials in a variety of optoelectronic applications including photodetection, energy harvesting, and light‐emitting devices. As perovskite solar cells are well studied in literature, here, the recent developments of organic–inorganic metal halide perovskite materials in optoelectronic devices beyond solar cells are summarized. The preparation of organic–inorganic metal halide perovskite films is introduced. Applications of organic–inorganic metal halide perovskite materials in light‐emitting diodes, photodetectors, and lasers are then highlighted. Finally, the recent advances in these optoelectronic applications based on organic–inorganic metal halide materials are summarized and the future perspectives are discussed.

This paper reviews the original achievements and advances regarding the field effect transistor (FET) fabricated from one of the most studied transition metal dichalcogenides: two-dimensional MoS2. Not like graphene, which is highlighted by a gapless Dirac cone band structure, Monolayer MoS2 is featured with a 1.9 eV gapped direct energy band thus facilitates convenient electronic and/or optoelectronic modulation of its physical properties in FET structure. Indeed, many MoS2 devices based on FET architecture such as phototransistors, memory devices, and sensors have been studied and extraordinary properties such as excellent mobility, ON/OFF ratio, and sensitivity of these devices have been exhibited. However, further developments in FET device applications depend a lot on if novel physics would be involved in them. In this review, an overview on advances and developments in the MoS2-based FETs are presented. Engineering of MoS2-based FETs will be discussed in details for understanding contact physics, formation of gate dielectric, and doping strategies. Also reported are demonstrations of device behaviors such as low-frequency noise and photoresponse in MoS2-based FETs, which is crucial for developing electronic and optoelectronic devices.

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Interest in two-dimensional (2D) polymers has increased rapidly since the isolation of graphene. However, approaches to the preparation of graphene-like materials still face great challenges. Herein we report a facile method to prepare single molecular thick 2D polymers by simply running the polymerization reaction in a flask without the aid of any templates and postmodification techniques. The strategy is to use the triptycene scaffold, a rigid three-dimensional skeleton, as one monomeric unit to substantially suppress the interlayer interaction between the as-formed polymeric 2D monolayers. The new individual monolayered 2D polymers float freely in solution and can be further transferred onto solid surface for characterization. It is also found that the resulting 2D polymeric monolayers can further evolve into monolayered or multilayered hollow spheres, which might be regarded as a model for the transformation of graphene to fullerene.