Physical vapor transport (PVT) is the most successful and widely used approach for bulk aluminum nitride (AlN) single crystals. During the process of PVT growing AlN crystals, crucible materials, the growth setup, and the growth parameters (e.g., temperature distribution, growth pressure) are crucial. This work proposes a detailed study on the PVT growth of single AlN crystals with sizes ranging from nanometers to centimeters. AlN crystals with different sizes are grown by spontaneous nucleation. Furthermore, it discusses and contrasts the growth conditions and mechanisms of AlN crystals with different sizes. The structural and optical properties of the AlN crystals are also involved.
Focusing on photoinduced crystal-to-crystal transformation system and architecture dependent property changes.
Photodriven isomerization of azobenzene cores.
Photodriven open-ring↔closed-ring transformations of diarylethene cores.
Photodriven [2 + 2] cycloadditions of olefin pair cores.
Other types of photoactive crystals.
Molecular architectures containing photosensitive units respond to light, giving dramatic variations of their structure. In particular, the crystalline packing phases offer the possibility of significant advances in crystal design and the understanding of solid-state photoreactivity. In this review we mainly focus on three different photoreactivity patterns, namely the isomerization of azobenzene, open-ring↔closed-ring transformations of diarylethenes and cycloadditions of olefin pairs, as well as some examples of photoreactive crystals outside these types. Many interesting phototriggered functionalities are documented herein, such as photo-tuning of guest adsorption of azobenzene or diarylethene-based porous frameworks and crystalline organic polymers generated by photo-cycloaddition reactions taking place in the different networks.