Synergistic weak/strong coupling luminescence in Eu-metal-organic framework/Zn2GeO4:Mn2+ nanocomposites for ratiometric luminescence thermometer

Abstract

Engineering novel ratiometric temperature sensors with high temperature sensitivity is still of a great challenge in versatile temperature measurement fields. Herein, a self-calibrated optical luminescent thermometer based on Eu3+/Mn2+ dual-activator was fabricated in the same nanocomposite system, which integrated the photoluminescence originated from the temperature-insensitive Eu-metal organic framework with weak coupling effect and the temperature-sensitive Zn2GeO4:Mn2+ with strong coupling effect. Specifically, the as-prepared nanocomposites composed of lanthanide MOF Eu-BTC (BTC = 1,3,5-benzenetricarboxylic acid) and Zn2GeO4:Mn2+ nanorods possessed Eu3+/Mn2+ dual red/green emission, which displays excellent ratiometric temperature-sensing functions and also has high relative sensitivity (Sr) of 4.1% ºC−1 when they are used as ratiometric luminescent thermometer in the physiological temperatures (25–45 °C). These results demonstrate that such a design strategy with synergistic weak/strong coupling luminescence is useful and the as-obtained Eu-MOF/Zn2GeO4:Mn2+ nanocomposites can be potential for temperature sensor applications.