Polarization Maintaining Fiber Temperature and Stress Gradient Sensitization Sensor Based on Semiconductor-Metal–Polymer Three-Layer Film Coating

Increasing sensitivity, measuring points, and stability have always been the pursuit of sensors. ZnSe9:CO1 and Ag composite nano films were coated on polarization maintaining fiber (PMF). Then, the coated PMF was nested in capillary and hose which was encapsulated with polydimethylsiloxane (PDMS) and epoxy resin. The integrated capillary sensor and thermoplastic hose sensor were prepared. The gradient sensitization of various measurement parameters such as temperature, stress, and micro bending is realized. The temperature sensitivity is 1.49 nm/°C, the micro bending sensitivity is 1.72 nm/102 g, and the stress sensitivity is 6.27 nm/mε. The sensors maintain good linearity and instantaneous response while having high sensitivity. By adjusting the length of PMF, the number of troughs is increased in the same band range, and different troughs have different sensitivities, which solves the inherent problem of cross sensitivity and realizes multiparameter measurement. Capillary sensors are used for remote safe real-time monitoring of mechanical overheating, and hose sensors are used for real-time monitoring of bridge load and human joint bending. This work is of great significance to the extension of the application range of optical fiber sensor

Capillary Sensors Composed of CdTe Quantum Dots for Real-Time In Situ Detection of Cu²⁺

CdTe colloidal quantum dots (CQDs) coated with glutathione (GSH) were prepared by aqueous synthesis. Based on the fluorescence selective quenching of CdTe CQDs in the presence of Cu2+, the CdTe CQDs were applied for ultrasensitive Cu2+ sensing. The detection limit of Cu2+ concentration was 0.055 μM. In order to realize real-time and rapid on-site detection, a capillary sensor composed of CdTe CQDs was prepared, and after drying at room temperature, heating at high temperature, and laser processing, the sensor achieved good response time and detection accuracy results. The detection of 1 × 10–5 mol/L Cu2+ concentration can be realized in 5–6 s. Moreover, the detection only needs to be carried out under an ultraviolet lamp, the cost of the sensor is low, and the detection method is very simple. The sensor requires only 3 μL of solution to be tested and can complete the detection, which not only saves the solution to be tested but also greatly improves the limit of the detection environment. A capillary sensor is of great significance for the real-time detection of natural environment and industrial wastewater

Capillary Sensors Composed of CdTe Quantum Dots for Real-Time In Situ Detection of Cu²⁺

CdTe colloidal quantum dots (CQDs) coated with glutathione (GSH) were prepared by aqueous synthesis. Based on the fluorescence selective quenching of CdTe CQDs in the presence of Cu2+, the CdTe CQDs were applied for ultrasensitive Cu2+ sensing. The detection limit of Cu2+ concentration was 0.055 μM. In order to realize real-time and rapid on-site detection, a capillary sensor composed of CdTe CQDs was prepared, and after drying at room temperature, heating at high temperature, and laser processing, the sensor achieved good response time and detection accuracy results. The detection of 1 × 10–5 mol/L Cu2+ concentration can be realized in 5–6 s. Moreover, the detection only needs to be carried out under an ultraviolet lamp, the cost of the sensor is low, and the detection method is very simple. The sensor requires only 3 μL of solution to be tested and can complete the detection, which not only saves the solution to be tested but also greatly improves the limit of the detection environment. A capillary sensor is of great significance for the real-time detection of natural environment and industrial wastewater

Capillary Sensors Composed of CdTe Quantum Dots for Real-Time In Situ Detection of Cu²⁺

CdTe colloidal quantum dots (CQDs) coated with glutathione (GSH) were prepared by aqueous synthesis. Based on the fluorescence selective quenching of CdTe CQDs in the presence of Cu2+, the CdTe CQDs were applied for ultrasensitive Cu2+ sensing. The detection limit of Cu2+ concentration was 0.055 μM. In order to realize real-time and rapid on-site detection, a capillary sensor composed of CdTe CQDs was prepared, and after drying at room temperature, heating at high temperature, and laser processing, the sensor achieved good response time and detection accuracy results. The detection of 1 × 10–5 mol/L Cu2+ concentration can be realized in 5–6 s. Moreover, the detection only needs to be carried out under an ultraviolet lamp, the cost of the sensor is low, and the detection method is very simple. The sensor requires only 3 μL of solution to be tested and can complete the detection, which not only saves the solution to be tested but also greatly improves the limit of the detection environment. A capillary sensor is of great significance for the real-time detection of natural environment and industrial wastewater

Capillary Sensors Composed of CdTe Quantum Dots for Real-Time In Situ Detection of Cu²⁺

CdTe colloidal quantum dots (CQDs) coated with glutathione (GSH) were prepared by aqueous synthesis. Based on the fluorescence selective quenching of CdTe CQDs in the presence of Cu2+, the CdTe CQDs were applied for ultrasensitive Cu2+ sensing. The detection limit of Cu2+ concentration was 0.055 μM. In order to realize real-time and rapid on-site detection, a capillary sensor composed of CdTe CQDs was prepared, and after drying at room temperature, heating at high temperature, and laser processing, the sensor achieved good response time and detection accuracy results. The detection of 1 × 10–5 mol/L Cu2+ concentration can be realized in 5–6 s. Moreover, the detection only needs to be carried out under an ultraviolet lamp, the cost of the sensor is low, and the detection method is very simple. The sensor requires only 3 μL of solution to be tested and can complete the detection, which not only saves the solution to be tested but also greatly improves the limit of the detection environment. A capillary sensor is of great significance for the real-time detection of natural environment and industrial wastewater

Capillary Sensors Composed of CdTe Quantum Dots for Real-Time In Situ Detection of Cu²⁺

CdTe colloidal quantum dots (CQDs) coated with glutathione (GSH) were prepared by aqueous synthesis. Based on the fluorescence selective quenching of CdTe CQDs in the presence of Cu2+, the CdTe CQDs were applied for ultrasensitive Cu2+ sensing. The detection limit of Cu2+ concentration was 0.055 μM. In order to realize real-time and rapid on-site detection, a capillary sensor composed of CdTe CQDs was prepared, and after drying at room temperature, heating at high temperature, and laser processing, the sensor achieved good response time and detection accuracy results. The detection of 1 × 10–5 mol/L Cu2+ concentration can be realized in 5–6 s. Moreover, the detection only needs to be carried out under an ultraviolet lamp, the cost of the sensor is low, and the detection method is very simple. The sensor requires only 3 μL of solution to be tested and can complete the detection, which not only saves the solution to be tested but also greatly improves the limit of the detection environment. A capillary sensor is of great significance for the real-time detection of natural environment and industrial wastewater

Simultaneous Real-Time Measurements of Temperature, Liquid Level, Humidity, and pH by ZnSe/Co Nanostructure-Coated Polymer Films

In this work, the surface of long-period fiber grating (LPFG) and polarization maintaining fiber (PMF) is functionalized based on the interaction between the resonance wavelength and external environment. LPFG coated with a 150 nm ZnSe/Co film is fixed on a hollow bracket, prestressed, and annealed many times. A highly sensitive liquid level sensor with adjustable sensitivity, an adjustable measurement range, and a high liquid level early warning is prepared. The waveguide layer controlled by humidity is constructed by filling poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT/PSS) in a periodically etched PMF. The surface is coated with a poly(vinyl alcohol) (PVA) and carbon nanotube (CNT) composite polymer. After laser processing, a honeycomb porous film is obtained, and the humidity sensor with wavelength modulation is prepared. The pH-sensitive polymer is successively adsorbed on the surface of PMF coated with a 120 nm indium tin oxide (ITO) film by electrostatic self-assembly (ESA). Poly(allylamine hydrochloride) (PAH), poly(acrylic acid) (PAA), and poly(styrene sulfonate) (PSS) constitute a composite film with rapid deposition and high permeability that is covered with polyaniline/poly(methyl methacrylate) (PMMA) as the protective layer. After laser processing, a fluffy porous film structure is formed. The pH sensor is obtained and the preparation steps are greatly reduced. Finally, based on the wavelength division multiplexing (WDM) and multiwavelength matrix (MWM), the problem of crosstalk is solved. An integrated sensor is constructed to realize the simultaneous measurement of temperature, liquid level, humidity, and pH. It has been successfully applied to monitor the overall environment of a chemical waste liquid storage tank. The sensor has the advantages of remote monitoring, safety, efficiency, and labor-saving