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We herein address the problem of polymorph selection by introducing a general and straightforward concept based on their ordering. We demonstrated the concept by the ordered patterning of four compounds capable of forming different polymorphs when deposited on technologically relevant surfaces. Our approach exploits the fact that, when the growth of a crystalline material is confined within sufficiently small cavities, only one of the possible polymorphs is generated. We verify our method by utilizing several model compounds to fabricate micrometric "logic patterns" in which each of the printed pixels is easily identifiable as comprising only one polymorph and can be individually accessed for further operations. [ABSTRACT FROM AUTHOR]

As fabrication and positioning of micro- and nanocrystals grow in importance in a wide range technological applications, there is an increasing requirement for the development of a shared technological platform that is able to process materials from solutions on large areas. Here, the application of lithographically controlled wetting (LCW) for the manipulation and positioning of single crystals directly on devices is reported. In the LCW, a stamp, consisting of a metallic grid, is positioned in contact with a liquid thin film spread on a substrate; under these conditions, the capillary forces pin the solution to the stamp protrusions, thus splitting the continuous film in separated droplets or channels. As the solvent evaporates and the solution reaches the saturation, the solute precipitates onto the substrate within the menisci, giving rise to a structured thin film, in correspondence of the protrusion of the stamp. The possibility to achieve a patterning of crystals of conjugated molecules with a defined shape and with controlled size directly on device is demonstrated and pattern of crystals are investigated using polarized optical microscopy, atomic force microscopy, X-ray diffraction; they are also electrically characterized. [ABSTRACT FROM AUTHOR]

Defects are inherent in transition metal dichalcogenides and significantly affect their chemical and physical properties. In this study, surface defect electrochemical nanopatterning is proposed as a promising method to tune in a controlled manner the electronic and functional properties of defective MoS₂ thin films. Using parallel electrochemical nanolithography, MoS₂ thin films are patterned, creating sulphur vacancy‐rich active zones alternated with defect‐free regions over a centimetre scale area, with sub‐micrometre spatial resolution. The patterned films display tailored optical and electronic properties due to the formation of sulphur vacancy‐rich areas. Moreover, the effectiveness of defect nanopatterning in tuning functional properties is demonstrated by studying the electrocatalytic activity for the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Many functional properties of organic semiconductors, such as charge transport, are regulated by structural order. The control of crystallinity, orientation, and positioning of crystals—the highest form of order—inside devices presents an extraordinary opportunity to fully exploit their potentialities. On page 2387, M. Cavallini and co‐workers demonstrate direct patterning of crystals of conjugated molecules onto devices, with defined shape and controlled size. [ABSTRACT FROM AUTHOR]