Concentration-Induced Phase Separation to Suppress Energy Transfer for High-Temperature Ratiometric Sensing in Organic Films

摘要

Energy transfer is usually applied in ratiometric thermometry, but it oftendecreases sensitivities due to much reduced distinguishment in the thermalresponses of two different-colored emitters. Herein, a feasible strategy torestrain energy transfer is utilized for achieving sensitive high-temperaturedetection, simply by increasing the dopant concentration to induce microphaseseparation. Atomic force microscopy phase images reveal that thisphase separation becomes dominant when the doping ratio reaches above40. This results in suppression of energy transfer, which is evidencedby systematic photophysical investigations. On this basis, by using heatresistantemitters, a series of inexpensive and easily prepared solid-filmorganic high-temperature ratiometric thermometers are developed. Theyexhibit a broad eye-detective sensing range of 102–236 ℃ with the relativesensitivity (S_r) higher than 0.5 K~(?1) and the maximum temperature resolutionattaining 0.39 K. Good reversibility and stability are also demonstrated inambient atmosphere.