Superior triethylamine sensing platform based on MOF activated by carbon dots for photoelectric dual-mode in biphasic system

Multimode sensors are required to enable detect of hazardous substances in different media. A sensing platform based on metal organic frameworks (MOF) and its derivatives was established to detect triethylamine (TEA) gas and TEA aqueous solution in the range of 1–100 ppm. The carbon dots (CDs) were selected as the light-energy conversion module to improve greatly the photoelectric performance of sensors. On the one hand, the dual-emission ratio type fluorescent sensor was built by CDs and MOF. The CDs@ZIF-8(In) showed excellent fluorescence emission enhancement at 440 nm and 610 nm in a dose-dependent manner when TEA was added. The change of fluorescence emission intensity of CDs@ZIF-8(In) sensor for TEA in water was at least 3 times than that of other volatile organic compounds, and its detection limit reached 1 ppm. On the other hand, the gas sensor based on MOF derivatives modified by CDs (CDs@DZIF-8(In)) displayed 3.5 times signal response than pure DZIF-8(In), reaching 374.6 to 100 ppm TEA. Moreover, the optimal operating temperature of CDs@DZIF-8(In) sensor was 40 ℃ lower than that of DZIF-8(In) sensor. The excellent fluorescence and electron transfer properties of CDs may play a key role in the design and modification of various types of sensors.