Phase-Selective Growth and 2D Fixation of Na(Gd1-xErx)S2 for Ultrasensitive Thermometry and Anti-Stokes Photon Imaging

The precise mapping of temperature distributions with laser-induced imaging is critical across diverse fields, from microelectronics to energy storage and biomedical engineering. Herein, phase-selective growth is conducted in a non-vacuum sulfur-rich environment, where NaGd 1-x Er x S 2 (NaGdS 2 -E x ) phosphors with high-efficiency up-conversion luminescence are successfully prepared. The ordered segregation of Er 3+ within the GdS 6 layers effectively suppresses non-radiative relaxation, producing a nonlinear quantum yield enhancement driven by an explosive surge in photon output upon increasing excitation power, which enables anti-stokes photon imaging. Furthermore, the microcrystals are successfully incorporated into NaGdS 2 -E x @polyacrylonitrile-polyurethane (NaGdS 2 -E x @PAN-TPU) membranes via electrospinning, achieving 2D fixation while preserving high luminescence efficiency, thereby expanding the application adaptability. Remarkably, the design of a thermally and non-thermal coupled upconverting based on the NaGdS 2 -E x @PAN-TPU system results in highly sensitive temperature sensing, achieving maximum relative sensitivities of 1.069 and 0.475% K −1 at 313 K. These findings provide a flexible platform, particularly for its potential in real-time visual thermometry within micro-nano electronic devices, while also paving the way for laser identification in maritime search and rescue operations.