Customizable self-supporting upconversion aerogels from assembly of nanowires

Lanthanide-based upconversion aerogels (UCAs) hold considerable promise for a variety of applications, including anti-counterfeiting, temperature sensing, and photoelectric devices. However, their potential is heavily hindered by the limitations of luminescent designability and functional versatility. Herein, we demonstrate the fabrication of self-supporting UCAs with customizable components and properties through a freeze-drying method using K 2 YF 5 -based upconversion nanowires as building blocks. The UCAs can function as an optical thermometer during their applications, such as thermal insulation. Moreover, the UCAs, mainly formed through ligand-mediated assembly of the nanowires, possess sectional adjustability and can accommodate other nanomaterials as functional dopants, exhibiting potential applications in multiplexed barcoding and water-resistant phosphor. Given the high tunability of the UCAs and tremendous functional nanomaterials, these results should shed light on arbitrary UCAs for diverse applications.