ZnS:Cu-Based Fluorescence and Surface Plasmon Resonance Triple Channel Sensor for Simultaneous Detection of Ultraviolet Intensity, Humidity, and Temperature

With the increasing demand for more powerful sensors, rapid development had been achieved. In this article, a fluorescence (FL) and surface plasmon resonance (SPR) triple channel sensor was designed based on wavelength division multiplexing (WDM). First, ZnS:Cu powder was mixed inside polydimethylsiloxane (PDMS) to detect ultraviolet intensity (UVI) and temperature as Channel 1. Second, we coated the thin core fiber (TCF) with 40-nm Ag film and carboxymethyl cellulose (CMC) to detect relative humidity (RH) as Channel 2. Third, another part of TCF was coated with 40-nm Ag, 4-nm ZnO film, and PDMS also to detect UVI and temperature as Channel 3. The detection range and compensation accuracy of UVI, RH, and T are 3.74–26.18 mW/cm2, 1.016; 20%–100% RH, 1.022, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5~^{\circ }$ </tex-math></inline-formula>C–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$41~^{\circ }$ </tex-math></inline-formula>C, 1.017. All the channels could be compensated to isolate single variation during simultaneous change. Compared with previous work, the first introduction of FL signal into SPR sensor in this article achieves three-channels integration inside one single-fiber structure, and all three parameters could be monitored simultaneously. The advantages of the proposed sensor, such as high accuracy, stability, and multiparameter simultaneous sensing, could be quite useful in future environmental monitoring field.