Ratiometric temperature sensing and molecular logic AND gate execution via Eu3+ doped BaWO4 nanophosphor

Abstract

Self-calibrated Luminescence thermometry (LT), a contactless temperature measurement technique has gained significant recognition owing to its idiosyncratic contours over conventional thermal sensors. Apart from high relative sensitivity, large operating thermal window, insignificant absolute error with minimum temperature uncertainty are perquisite requirements for feasible endeavor of the developed temperature sensors. In the current work, after efficaciously preparation of Eu3+ doped BaWO4 via hydrothermal route, the inherent thermally coupled energy levels (TCEL) 5D1 and 5D0 of Eu3+ were employed for ratiometric temperature sensor design in 80–500 K range. The intense down-shifting luminescence and high temperature sensitivity elicit small temperature uncertainty (0.05 K) and a low absolute error (−0.12 to 0.14 K). Nevertheless, along with good repeatability (>95%) in thermal cycles, the prepared nanophosphor also demonstrates good stability (after repeated thermal cycles). Additionally, carried out Judd-Ofelt analysis provides significant insight in LT based upon emission behavior of Eu3+. A high value of relative sensitivity (1.65% K−1 and 2.95% K−1 from decay kinetics and ratiometric respectively) with chromaticity shift of 78* 10−3 manifests a visual change in inherent red emission profile from the prepared phosphor. Further, exploiting heat and incident UV as input, the prepared phosphor material is utilized to develop an exclusive dry molecular logic gate (here AND) implementation. As versatile spectroscopic probe, Eu3+ ion was exercised for details structural analysis to disclose the change of local site symmetry in BaWO4 due to aliovalent substitution.