Self-referenced dual-near-infrared emission-based sensor platform for the ultrasensitive discrimination of D2O and H2O

Due to its chemical and physical similarities, the ultrasensitive discrimination of D2O in the presence of H2O remains a practical challenge. In this study, we present an approach to utilize the near-infrared (NIR) optical properties of H2O. Specifically, the absorption coefficient of H2O at approximately 980 nm, which is derived from the second overtone of the O–H stretching mode of H2O, exhibits a notable distinction from that of D2O. To this end, we construct and optimize a dual-NIR emissive lanthanide-doped nanoprobe with a strong emission intensity at 980 nm. In addition, to enhance the reliability of the proposed sensor platform, we introduce a self-referenced signal at 865 nm, which shows a stable signal intensity in both H2O and D2O. Our self-referenced dual-NIR emission-based sensor platform successfully discriminates between D2O and H2O and shows ultrasensitive discrimination capabilities with a limit of detection of 0.17 nM, which has the highest sensitivity among that of previously reported D2O sensors.