Electrospun rhodamine@MOF/polymer luminescent fibers with a quantum yield of over 90%

Tailored luminescent guest@metal-organic framework (Guest@MOF) materials with outstanding photophysical properties are enabling materials for emergent technologies in smart sensors and optoelectronics. However, the practical utility of Guest@MOF currently is impaired by its poor stability and difficult-to-handle powder form. Here, we combine a luminescent-sensing Guest@MOF system with a non-luminescent polymer matrix and, for the first time, demonstrated the easy-to-apply electrospinning of luminescent fibers comprising nanocrystals of RhB@ZIF-71 (rhodamine B@zeolitic imidazolate framework-71) homogeneously dispersed in a polyvinylidene difluoride (PVDF) matrix. The luminescence of RhB@ZIF-71/PVDF fiber is tunable and exhibits a quantum yield exceeding 90%. Compared with RhB fluorophore in PVDF fiber, the ZIF-71 (host) protects the nanoconfined RhB guest molecules (especially the J-aggregates of RhB), giving the composite fiber its unique thermofluorochromic response and enhanced thermal stability to 200°C. Our results reveal the exciting opportunities for implementing electrospun luminescent fibers functionalized with bespoke Guest@MOF nanocrystals for multifunctional device applications.