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Environmental changes, such as applied medication, nutrient depletion, and accumulation of metabolic residues, affect cell culture activity. The combination of these factors reflects on the local temperature distribution and local oxygen concentration towards the cell culture scaffold. However, determining the temporal variation of local temperature, independent of local oxygen concentration changes in biological specimens, remains a significant technological challenge. The process of triplet–triplet annihilation upconversion (TTA-UC), performed in a nanoconfined environment with a continuous aqueous phase, appears to be a possible solution to these severe sensing problems. This process generates two optical signals (delayed emitter fluorescence (dF) and residual sensitizer phosphorescence (rPh)) in response to a single external stimulus (local temperature), allowing the application of the ratiometric-type sensing procedure. The ability to incorporate large amounts of sacrificial singlet oxygen scavenging materials, without altering the temperature sensitivity, allows long-term protection against photo-oxidative damage to the sensing moieties. Translucent agarose/silk fibroin hydrogels embedding non-ionic micellar systems containing energetically optimized annihilation couples simultaneously fulfill two critical functions: first, to serve as mechanical support (for further application as a cell culture scaffold); second, to allow tuning of the material response window to achieve a maximum temperature sensitivity better than 0.5 K for the physiologically important region around 36 °C.

We propose and demonstrate a novel ammonia gas and temperature sensor based on a femtosecond laser inscribed small-period long-period fiber grating (SP-LPG) coated with a nano-assembled polyelectrolyte thin film composed of poly(diallyldimethylammonium chloride) (PDDA)/poly(acrylic acid) (PAA). The PDDA/PAA film is deposited onto the SP-LPG via layer-by-layer electrostatic self-assembly. The SP-LPG is inscribed in a single mode fiber with a period of 30 μm and the total length is only 3 mm. The designed period is much smaller than that of the conventional long period fiber grating (LPFG) of several hundred microns, so we can not only see high-order cladding modes in the transmission spectrum, but also a series of Bragg resonance peaks in the reflection spectrum. The concentration of ammonia gas is detected by the wavelength shift of the transmission resonance dip. The ambient temperature is monitored by the wavelength shift of the Bragg resonance peak. Because the Bragg resonance peak is insensitive to refractive index, we can measure ammonia gas and temperature simultaneously. The experimental results show that the detection limit of the sensor is less than 0.1 ppm. The sensor is sensitive only to ammonia when exposed to different gases. The temperature sensitivity of the sensor is about 8.7 pm/℃ from 30℃ to 70℃. Compared with traditional LPFG, SP-LPG has a more compact structure and the special ability to monitor temperature in real time, which makes the device more advantageous in practical applications. • The proposed SP-LPG was first ever applied to gas sensing. • The SP-LPG was fabricated efficiently and economically by femtosecond laser writing. • Simultaneous detection of ammonia gas and temperature was achieved. • The SP-LPG was easier for integration and miniaturization. [ABSTRACT FROM AUTHOR]

• The Sc 6 WO 12 : Yb3+/Er3+ with strong upconversion red emission were prepared by high-temperature solid phase method. • The optimal doping concentrations of Yb3+ and Er3+ ions in Sc 6 WO 12 were determined to be 0.05 and 0.02, respectively. • The strong red upconversion emission mechanism of the Sc 6 WO 12 : Yb3+/Er3+ phosphor was confirmed as Yb3+(2F 5/2) + Er3+(4I 13/2) → Yb3+(2F 7/2) + Er3+(4F 9/2). • Sc 6 WO 12 : Yb3+/Er3+phosphors have a broad prospect for non-contact temperature sensing applications. Herein, a strong red upconversion phosphor of Yb3+/Er3+ co-doped Sc 6 WO 12 was prepared by employing an equivalent substitution approach. When irradiated by 980 nm near-infrared laser, the phosphor emits strong 660 nm red light. The main excitation mechanism for its red upconversion luminescence emission is the energy transfer process, through which the Er3+ ions is promoted from the 4I 13/2 energy level to the 4F 9/2 energy level. In addition, it is noteworthy that the multimode upconversion luminescence phosphor exhibits three different trends upon temperature change, and its upconversion emission integral intensity ratio exhibits a linear relationship with temperature in the range of 298 K–623 K. This special property makes the phosphor promising for applications in optical temperature measurement. [Display omitted] [ABSTRACT FROM AUTHOR]

Textile-integrated wearable sensors have exhibited an immense potential to transform human life by fetching safety and comfort at the forefront. This work underscores a novel design approach to fabricate textile-integrated multimodal sensors using a conductive ink coated bi-stretch nylon fabric. Conductive ink has been formulated by dispersing high aspect ratio silver nanowires into water-dispersed PEDOT: PSS solution with polyvinylpyrrolidone that allows sensing of various stimuli, including mechanical strains, temperature, humidity, etc. The fabrication of sensing elements involves the interleaving of screen-printed conductive ink into flexible coats, using water-borne polyurethane, achieved by the facile pad-dry-cure technique on bi-stretch fabric like a sandwich. Remarkable mechanical strain sensing performance in terms of sensitivity, repeatability, and stability has been demonstrated along with flexibility, bendability, and compliant form factor, making them suitable for applications in wearable technology and smart textiles. Moreover, the temperature and humidity sensing exhibit rapid response and wide detection ranges, making the sensor adaptable to diverse environmental conditions. The sensing fabric responds well to different strain and compression conditions. The as-developed fabric can also operate as an IR heating element when biased at certain operating conditions. These attributes make such elements an ideal candidate for various applications, such as human motion tracking, environmental monitoring, and healthcare devices. The sensor's low-cost, solvent-free production and scalability make it a practical choice for mass adoption. [Display omitted] • Silver nanowires integrated functional ink was synthesized using polyol method. • PEDOT: PSS was used as a conducting polymer blend to impart resilient sensing performance. • The conductive ink interleaved between the two coats of water-borne polyurethane. • Functional ink coated on nylon fabric exhibited extreme sensitivity to various stimuli. • Multimodal sensor performance in terms of environment, health, etc as a wearable patch is projected. [ABSTRACT FROM AUTHOR]

In recent years, non-contact temperature reading sensors based on carbon quantum dots (CQDs) have attracted a lot of attention, most researchers have studied them at room temperature and high temperature. In this paper, red-CQDs (R-CQDs) was synthesized by hydrothermal method using o -phenylenediamine and chemically characterized by transmission electron microscopy, Fourier transform spectroscopy and X-ray photoelectron spectroscopy. The bandgap energy of R-CQDs was calculated from the absorption spectra, and the photoluminescence (PL) spectra at different laser powers showed that the PL of the R-CQDs were single-photo absorbing process. For better application, R-CQDs/polyvinyl alcohol (PVA) films were prepared. The PL properties of the film were studied. Experiments show in temperature range of 190∼260 K, the PL intensity decreases linearly with increasing temperature. Relative sensitivities of temperature sensing were calculated to be about −0.62% K−1. This work demonstrates the feasibility of its application in low temperature sensing. • We have synthesized R-CQDs with good photoluminescence properties using a simple method. • In the low temperature range of 190 ∼ 260 K, the R-CQDs/PVA film's have good temperature-dependence. • Relative sensitivities of temperature sensing were calculated to be about −0.62% K−1. [ABSTRACT FROM AUTHOR]

• A novel kind of UC materials NaLaTi 2 O 6 :Yb3+,Er3+/Ho3+ were developed. • Both TCLs and NTCLs were used to assess the temperature sensitivity. • High S a and S r were determined to be 0.0374 K-1 (293 K) and 0.970% (293 K). To satisfy the increasing necessity of contactless optical thermometry, utilizing both thermally coupled (TCLs) or non-thermally-coupled (NTCLs) energy levels of rare earth ions in novel phosphors has significant potential for devising the optical thermometers with high temperature sensitivity. Herein, a sequence of novel Yb3+,Er3+/Ho3+ doped NaLaTi 2 O 6 (NLTO) phosphors were sintered using a high-temperature solid-state reaction approach. Structure, phase component and luminescence performance were identified in detail. Upon 980 nm near-infrared (NIR) excitation, the obtained materials presented typical Er3+/Ho3+ characteristic emission wavelengths in visible region, which include two green emission bands around 522 and 543 nm, as well as a weaker red band around 661 nm for Er3+ doped NLTO, a green emission band around 545 nm and a red band around 657 nm for Ho3+ doped NLTO. Besides, a unusual emission band around 757 nm of Ho3+ in visible edge region was also clearly found. The temperature sensing properties of representative NLTO:Yb3+,Er3+/Ho3+ samples were assessed based on the fluorescence intensity ratio (FIR) technique of TCLs or NTCLs energy levels. The maximal absolute sensitivity (S a) and relative sensitivity (S r) were determined to be 0.0374 K-1 (293 K) and 0.970% K-1 (293 K) by taking the FIR of NTCLs 2H 11/2 →4I 15/2 and 4F 9/2 →4I 15/2 transitions in NLTO:Yb3+,Er3+. Simultaneously, the maximal S a and S r were 0.0306 K-1 (573 K) and 0.776% K-1 (373 K) using the FIR of NTCLs 5F 5 →5I 8 and 5F 4 ,5S 2 →5I 7 transitions in NLTO:Yb3+,Ho3+. Consequently, the temperature sensitivities above can be compared to reported results, which indicate that as-prepared materials have a promising application in optical temperature sensors field. FIR temperature sensing properties in NaLaTi 2 O 6 :Yb3+,Er3+/Ho3+ phosphors were investigated in this work. [Display omitted] [ABSTRACT FROM AUTHOR]

Schematic diagram of experimental procedure followed in the present work. [Display omitted] • Er3+/Yb3+ doped CaMoO 4 nanophosphors synthesized via a microwave assisted approach. • Analysis of optical properties, antibacterial traits and their integration with temperature sensing. • Potential prospect of the as-synthesized material in food preservation, medical equipment, water treatment, and solid state luminous devices. Due to their exceptional intrinsic optical characteristics, molybdate compounds have aroused significant attention in recent years for their effective up and downconversion luminescence. In the present study, a series of x Er3+/Yb3+ (x = 0.5 %, 1 %, 2 %, 4 % and Yb3+ =15 %) doped CaMoO 4 nanophosphors synthesized through a microwave assisted approach and subsequently the comprehensive analysis of the functionalities such as optical properties, antibacterial traits and their integration with temperature sensing, have been explored. Furthermore, the structural refinement confirms the occurrence of tetragonal scheelite phase of the prepared materials. The morphology of the material was identified by FE-SEM and HR-TEM analysis which reveals particles are in spherical shape. Up-conversion luminescence intensities were found to be dependent on doping concentration, laser excitation power and external temperature upon 980 nm light excitation. The temperature sensing response of the optimized sample was examined based on intensity ratio of two emission bands that involves thermally connected energy levels of Er3+ ion. The maximum absolute sensitivity of 10.74 × 10−3 K−1 (at 500 K) was found, demonstrating its potential application in high temperature thermometry. The comprehensive analysis and the outcome of the present study suggests the potential prospect of the as-synthesized material in food preservation, medical equipment, water treatment, and as an optical coating agent for solid state luminous devices. [ABSTRACT FROM AUTHOR]

• This study is the first to show that a DCSHF-based interferometric temperature sensor is more sensitive than common multimode interferometer. • Alcohol-filled DCSHF shows a much greater enhancement in temperature sensitivity compared to ordinary hollow optical fibers. • A microsphere is innovatively inserted into alcohol-filled DCSHF to significantly enhance temperature sensitivity. In this paper, a temperature sensing structure comprising single-mode fiber (SMF) and dual-core single-side hole fiber (DCSHF) is introduced and demonstrated to enhance temperature sensing performance based on modal interference. The biased air hole of DCSHF minimizes temperature-induced variations in the effective refractive index of the core mode, resulting in high sensitivity of temperature sensing. For further enhancement, alcohol with a high thermo-optical coefficient is introduced into the air hole, while barium titanate microsphere is innovatively inserted as coupling factor to enhance mode coupling efficiency. The experimental results prove that the maximum sensitivity of this sensor can reach up to −5.57 nm/°C. The sensor offers advantages such as simple preparation, high sensitivity, excellent repeatability, rapid response, and remarkable stability, suggesting wide-ranging potential applications in temperature sensing. [ABSTRACT FROM AUTHOR]

Flexible wearable sensors with bimodal functionality offer substantial value for human health monitoring, as relying on a single indicator is insufficient for capturing comprehensive physiological information. However, bimodal sensors face multiple challenges in practical applications, including mutual interference between various modalities, and integration of excellent mechanical properties, interfacial adhesion, environmental adaptability and biocompatibility. Herein, the multifunctional hydrogel, synthesized through radical grafting and supramolecular self-crosslinking reactions, exhibits excellent thermal sensitivity (TCR = -1.70% °C -1 ), high toughness (9.31 MJ m - 3 ), wide strain range (0-600%), outstanding adhesion strength (36.07 kPa), antifreeze, visualization, water retention, biocompatibility, antibacterial and antioxidant capabilities. Leveraging its excellent conductivity, this hydrogel can be applied in electroluminescent, triboelectricity, electromyography monitoring, and message encryption. Moreover, the hydrogel is fabricated as bimodal smart sensors for strain and temperature monitoring. To avoid mutual interference between the two signals, a wearable system in "IS"-shaped configuration is innovatively designed based on finite element simulation results. The integration of "IS"-shaped hydrogel, flexible circuit modules, and data transmission form a closed-loop wearable platform for rehabilitation training of patients with arthritis or joint surgery. This strategy establishes a bimodal decoupling and self-calibrating system utilizing a single material to accurately detect multiple parameters, advancing wearable electronics and personalized medicine., (© 2025 Wiley‐VCH GmbH.)