In Situ Self‐Assembly of Ultrastable Crosslinked Luminescent Gold Nanoparticle and Organic Dye Nanohybrids toward Ultrasensitive and Reversible Ratiometric Thermal Imaging

Abstract Exploring hybrid nanomaterials with sensitive and reversible ratiometric temperature sensing is highly desirable but still challenging. Herein, using thermosensitive Pluronic F127 as a template, a facile and straightforward approach is presented for one‐pot synthesis of dual‐emitting nanohybrids of crosslinked gold nanoparticle (AuNP) and organic dye with unique core–shell structure and excellent stability, which can be utilized as an ultrasensitive and reversible ratiometric temperature sensor. The dual‐emitting nanohybrids are achieved through in situ self‐assembly of red‐emitting AuNPs in the hydrophobic core, along with doping blue‐emitting and polarity‐responsive hydrophobic dye 4,4′‐bis(2‐benzoxazolyl) stilbene (BBS). The AuNP and BBS nanohybrids (AuNP–BBS nanohybrids) consist of about ten crosslinked ultrasmall AuNPs in the hydrophobic core. The crosslinking interaction between multidentate thiol ligand and ultrasmall AuNPs offers remarkable stability without dye leakage, while the thermosensitive Pluronic F127 endows the nanohybrids with two reverse signal responses toward temperature. By virtue of the excellent features, the dual‐emitting AuNP–BBS nanohybrids can be capable of ratiometric sensing of temperature with remarkable reversibility and high sensitivity (0.3396 °C⁻¹), and enable visual temperature measurements by the naked eye and pseudocolor imaging. These findings provide a useful guidance for preparing uniform hybrid nanomaterials with remarkable stability and desired functions.