Lanthanide cation encapsulated in a metal–organic framework as a white LED and selective naked-eye reversible HCl sensor

A prepared anionic HPU-14, which was employed as a platform for loading green-emitting Tb³⁺ and red-emitting Eu³⁺ into nanotube channels of the blue-emitting MOF via an ion-exchange process, is suitable for white light-emitting LED devices and enables the sensitive colorimetric reversible detection of gaseous HCl.