The concept of van der Waals solid solutions has been demonstrated to yield photon upconversion (UC) organic crystals with extraordinary performance, opening a domain of versatile dispersion-force-based systems in the quest for superior UC solids.

Visible-to-UV upconversion shorter than 340 nm was achieved in organic solvents and the solvent dependent efficiency and photostability were elucidated.

Completely solvent-free “green” formation of bicomponent organic polycrystalline films for efficient visible-to-ultraviolet photon upconversion (UV–UC) were achieved by temperature-gradient solidification from the melt. The UV–UC film formed under optimal conditions...

To generate large single crystals of 3D covalent organic frameworks, the active use of ionic additives, which can greatly impact crystal size, is proposed. The crystal size ranking was found...