Bioinspired CS@PAN Electrospun Fibrous Aerogels with Vertical Capsule Vessels for Self-Feedback Temperature Sensing

Unconventional sensors with characteristics of portability, safety, remote manipulation, and high spatiotemproal resolution are highly desirable to detect varied temperature under specific conditions such as local temperature fields of the microenvironment. Herein, a 3D high-performance optical thermometry platform driven by the up-conversion green fluorescence of Er³⁺/Yb³⁺ co-doped electrospun fibrous aerogels is developed. The system simply consists of polycrystalline-encapsulated (Y_1-x-yEr_xYb_y)₂O₂S/polyacrylonitrile (YOS-EY/PAN) electrospun fibers and chitosan (CS). The flexible fibers form a hierarchically ordered bionic cellular structure through bio -based cross-linking, which avoids toxic chemical cross-linking. Additionally, the intense green emission is ascribed to ²H-_11/2/⁴S_3/2 -> ⁴I_15/2 transitions, as the main indicator to determine the relative sensitivity of 1.22% K^-1 at 303 K. More importantly, multipoint dispersed lanthanide (Ln) between cell walls confers stronger temperature sensing capability to aerogels. The successful strategy provides insights for the development of luminescence thermometry and opens a window for multidimensional temperature sensing.