The thermal quenching effect of phosphors has long constrained their application in high-temperature environments. Exploring well-defined thermal quenching regulation strategies is crucial for enhancing the thermal stability of phosphors. However, current research on achieving thermal quenching resistance by regulating the bandgap shift of intervalence charge transfer (IVCT) is still relatively limited. In this study, we effectively controlled the IVCT bandgap position by adjusting the Mg/Ca ratio (x = 0, 1/3, 2/3, 1) in Mg1-xCaxNb2O6:Pr3+. The results show that as x increases from 0 to 1, the IVCT energy level rises from 3.687 eV to 4.265 eV, increasing the Pr3+ 3P0 electron population and effectively compensating for the reduction in D-1(2) emission during heating. Within the temperature range of 298 K-498 K, the integrated emission intensity of all samples except MgNb2O6:Pr3+ remains stable at 92%-105%; at 573 K, it still maintains 80%-91%. Additionally, this phosphor demonstrates promising application prospects in the field of optical temperature sensing. The maximum absolute sensitivity (Sa) and relative sensitivity (Sr) of the temperature sensing scheme based on the charge transfer band (CTB) and IVCT intensity ratio of the excitation spectrum reached 3.57% at 473 K and 1.70% at 398 K, respectively; the maximum Sa and Sr of the temperature sensing scheme based on the CIE coordinate X intensity ratio reached 3.47% at 573 K and 10.25% at 573 K, respectively. This study confirms the effectiveness of the IVCT bandgap shift strategy in enhancing the thermal stability of phosphors and provides new insights into its application in temperature sensing.

In recent years, enhancing the luminescence thermal stability of rare-earth-ion-doped phosphors has emerged as a research hotspot. This study proposes and validates an innovative dual-compensation strategy that significantly improves the luminescence thermal stability in the Na5Y(WO4)4: Sm3+, Pr3+ phosphor system through synergistic modulation of charge transfer band (CTB) red-shift and defect engineering. Under the CTB red-shift-dominated compensation regime, the Na5Y(WO4)4:5%Sm3+ phosphor exhibits optimal thermal stability when excited at 267 nm (CTB red-shift), demonstrating an integrated emission intensity at 573 K reaching 1.24 times the 298 K reference value. Under the defect-engineering-dominated compensation mechanism, this phosphor achieves peak thermal stability under 405 nm excitation (f-f transition), with its integrated emission intensity at 573 K enhanced to 1.31 times the 298 K reference. Furthermore, the Na5Y(WO4)4:Pr3+ phosphor also manifests exceptional luminescence thermal stability through the dual-compensation strategy. This study innovatively establishes a dual-model fluorescence intensity ratio (FIR) optical thermometry system based on the thermal response characteristics of phosphors. The Na5Y(WO4)4:1%Sm3+ phosphor achieves a maximum relative sensitivity of 4.01% K-1 (298 K FIR). This dual-model strategy confirms that the Na5Y(WO4)4: Sm3+, Pr3+ system combines exceptional high-temperature luminescence stability with high-precision temperature-sensing performance, demonstrating substantial application potential in optical sensing under extreme thermal environments.

Isochoric freezing offers a CPA-free technique for low-temperature storage of biological samples, enhancing their stability, transportability, and potential for clinical organ transplantation. Conventional isochoric systems exploit the pressure-temperature coupling in a rigid, sealed chamber to suppress uncontrolled ice growth but lack precise spatiotemporal control over ice-nucleation events, leading to stochastic freezing and reduced preservation efficiency. Here, we present a double-phasic isochoric system that physically separates the sample chamber (sample solution) from an external nucleation chamber (freezing solution) and verify its stability across diverse liquid media, including pure water, saline, HTK, and UW. By introducing cholesterol-crystal nucleators into the freezing solution, we achieve controlled ice nucleation that directs crystal formation away from the sample chamber and generates endogenous pressure to sustain supercooling (43.8 ± 3.7 MPa at -4 °C), reducing random freezing incidence by 50%. After optimizing the sample container, we performed 24  h of isochoric freezing of HEK293T cells in 7  mL PE tubes at -4 °C, retaining 92 ± 3.1% viability; following 72  h, the cells exhibited superior proliferation and lower ROS damage compared with conventional 4 °C static cold storage (SCS). Applied to rat kidneys, 72  h of isochoric preservation decreased tissue malondialdehyde by 64 ± 6.2%, preserved Na+/K+-ATPase activity, and maintained histological integrity relative to SCS. This study establishes critical methodology for clinical translation of isochoric freezing and demonstrates its promise for extending organ preservation times and improving transplant viability.

Phosphor-based luminescence thermometry has become a very promising technology, which is used for noncontact, remote and spatially resolved temperature sensing in various fields from microelectronics and biomedicine to harsh environment. This method takes advantage of the inherent temperature dependence of specific photoluminescence characteristics of doped inorganic phosphors. In this study, K3LuSi2O7 as the host, doped with rare earth element Europium ion (Eu3+), adjusted the excess degree of K+, and explored antithermal quenching performance. Through thermal activation, we achieved Charge Transfer Band (CTB) edge red-shift, which led to thermally enhanced luminescence under excitation at the position of CTB edge. At 573 K, the comprehensive luminous intensity of the phosphor reached 8.144 times as high as that at 298 K. And the excess degree of K+ also has a positive effect on the antithermal quenching performance of the phosphor. This provides an effective way for thermal enhanced luminescence of Eu3+-doped phosphors. We found that both excitation at the CTB main peak position and excitation at the Eu3+ 4f -> 4f transition position exhibited thermal quenching. Therefore, based on completely opposite thermal responses dependent on distinct excitation position, we simultaneously establish two kinds of optical thermometry: single-band radiometric (SBR) optical thermometry and dual-band radiometric optical thermometry, with a maximum sensitivity of 2.701 % @523 K. Moreover, this phosphor exhibits exceptionally stable red emission under specific excitation position. This work provides a novel and viable strategy for optical thermometry using Eu3+-doped phosphors.

Cadmium-free indium phosphide (InP) quantum dots (QDs) are promising emitters for environmentally benign next-generation light-emitting diodes (LEDs), yet their application is hindered by poor operational stability. This limitation arises from electron trapping and exciton quenching at the InP/ZnMgO interface, where delocalized electrons from InP QDs are readily captured by oxygen vacancies (OV) in ZnMgO. Here, we demonstrate highly stable InP-based QD-LEDs by rationally passivating ZnMgO with organic fluoride ions (F-). The strong binding affinity of F- effectively passivates OV sites and suppresses ion migration under electrical injections, thereby lowering defect density and mitigating nonradiative recombination at the interface. As a result, we achieve red InP QD-LEDs with a peak external quantum efficiency (EQE) of 25.35% and a maximum luminance of 137 464 cd m-2. Remarkably, the T95 operational lifetime at 1000 cd m-2 extends to 1504 h. Furthermore, InP QDs exhibit excellent compatibility with the micro-LED configuration, maintaining an EQE of 23.29% at a micropixel size of 2 µm. These results highlight a viable pathway toward efficient, stable, and environmentally benign InP-based micro-LEDs for next-generation near-eye displays.

In situ cryopreservation within multi-well plates is a promising strategy for parallel biospecimen storage, yet it is critically limited by the lack of rapid and uniform rewarming techniques. This study presents an integrated electromagnetic induction heating system designed to address this bottleneck. A novel multi-well plate was developed, featuring integrated heaters that serve as internal heating elements upon immersion in the sample solution. Through systematic investigation and optimization of key parameters-including heater position, coil geometry and size, plate architecture, and the implementation of a field shaper-the system achieved a maximum rewarming rate of 762.4 degrees C/min while maintaining a maximum temperature difference below 6 degrees C across the optimized multi-well configuration. This performance represents a 25-fold increase in rewarming rate compared to conventional hotplate methods. The findings provide a scientific basis for parameter selection in induction-based rewarming and establish an efficient and reliable plate-scale rewarming strategy. This technology provides a critical thermal engineering framework and hardware foundation for future in situ preservation studies.

Optical thermometry based on the fluorescence intensity ratio (FIR) of rare-earth ions has developed over the past decade into a practical non-contact temperature-sensing platform, valued for its fast response and immunity to electromagnetic interference. Among the FIR variants, the temperature-induced redshift of the charge transfer band (CTB) differs: it circumvents the relative-sensitivity ceiling inherent to conventional thermally coupled level (TCL) thermometry, raising the achievable S_r from the ∼1–2% K−1 range into the 5–9% K−1 range. This Review covers the physical mechanism of CTB redshift, seven host families (vanadates, tungstates, molybdates, niobates, silicates/aluminosilicates, germanates, and double perovskites), five thermometric strategies (CTB-redshift SBR, excitation-spectrum FIR, CTB + TCL synergy, CTB + IVCT synergy, and multi-mode thermometry), and the design principles governing material performance (crystal-field engineering, composition tuning, charge compensation, energy transfer, and nanocrystallization). Open challenges and future directions are discussed.

A facile evaporation crystallization method has been utilized to develop the Sb3+ and Ln3+ (Er3+, Ho3+, Dy3+, or Sm3+)-codoped Cs2NaLuCl6 double perovskite crystals. This synthesis route is simple to operate and merely needs mild reaction conditions, which can be promising for large-scale production. The Sb3+ and/or Ln3+-doped Cs2NaLuCl6 products exhibit high crystallinity and excellent luminescent performance. The emission of the phosphors consists of the self-trapping excitation (STE) of [SbCl6]3- and f-f transitions of Ln3+. A wide-spectrum emission color modulation is achieved by adjusting the doping level of Ln3+, wherein the effective energy transfer coupling between STE and Ln3+ is the critical factor governing spectral color manipulation. Notably, the luminescence intensity of STE is significantly enhanced, although energy transfer occurs. This result indicates that the codoping of Ln3+ can simultaneously introduce new activator ions and enhance the blue emission of STE in Cs2NaLuCl6 double perovskites. Furthermore, the Sb3+ and Er3+/Ho3+-codoped Cs2NaLuCl6 materials not only feature down-conversion luminescence and exhibit up-conversion emissions under near-infrared (NIR) excitation but also display dazzling multicolor light under LED chip excitation. These results indicate that the as-synthesized Sb3+/Ln3+-codoped Cs2NaLuCl6 materials have potential applications in the fields of multimode optical anticounterfeiting and solid-state lighting.

Quantum dot light-emitting diodes(QLEDs) have attracted extensive attention in high-resolution displays and emerging fields such as augmented reality due to their narrow emission spectra, wide color gamut, high brightness, and low power consumption. However, the electroluminescent efficiency and stability of blue devices remain significantly inferior to those of red and green devices, and the lack of high-performance pure blue quantum dots(QDs) has limited the development of full-color displays. In this study, we report a synthesis strategy based on a ZnSe core with Cd ion-mediated emission tuning. CdZnSe core QDs were successfully prepared by rapid Cd2+ injection under high-temperature conditions to induce ion exchange, achieving an emission peak at 469 nm with a photoluminescence quantum yield(PLQY) of 79%. Subsequently, a multilayer shell structure of ZnSe/ZnSeS/ZnS was epitaxially grown on the core QDs, effectively passivating surface defects, enhancing structural stability, and significantly suppressing non-radiative recombination. The resulting multilayer-capped QDs exhibited a stable emission peak at 463 nm with a PLQY further increased to 92%, showing pure blue emission. QLED devices fabricated using these QDs demonstrated excellent electroluminescent performance, with a peak external quantum efficiency(EQE) of 18. 5% and a maximum brightness of 6. 34 & times;10(4) cd/m(2). In summary, this strategy, combining ion exchange with multilayer shell passivation, enables the fabrication of high-PLQY, stable pure blue QDs and high-performance QLED devices.

The development of microwave photonics requires monolithic integration of functional thin-film layers on low-loss substrates, but epitaxial film growth is limited to materials with compatible crystal structure and chemistry, hindering the flexibility of device design. Herein, high-quality epitaxial BaTiO3 thin films are fabricated onto low-loss, non-perovskite substrates, including sapphire and amorphous fused silica, via a flexible freestanding SrTiO3 template strategy. Templated growth on SrTiO3 membranes results in highly aligned in-plane polarization and well-defined domain switching characteristics in BaTiO3 thin films, leading to an effective Pockels coefficient of 202 pm/V and a dielectric tunability up to similar to 30% at 110 GHz. The Cole-Cole modeling analysis further reveals a bias-dependent relaxation behavior bridging high-frequency polarization modes with domain wall dynamics. By overcoming lattice mismatch and thermal expansion constraints of heteroepitaxial growth on rigid substrates, this freestanding template approach provides a versatile and potentially scalable strategy for monolithic integration of BaTiO3 films, enabling high-performance multifunctional microwave photonic systems.

Natural deep eutectic solvents (NADES) represent a class of low-toxicity cryoprotectants with promising application prospects, serving as sustainable alternatives to conventional cryoprotective agents. This study systematically evaluated the cryoprotective performance of two NADES formulations composed of l-proline and glucose at molar ratios of 1:1 (PG11) and 5:3 (PG53). Through systematic investigation of their cytotoxicity, ice inhibition capacity, viscosity, and cellular permeability─key physicochemical and biological properties─combined with coordinated optimization of the cooling rate and loading time, we successfully developed an efficient cryopreservation strategy that eliminates the need for programmable cooling equipment. FTIR-ATR spectroscopy confirmed the presence of extensive hydrogen-bonding networks within the NADES systems, accounting for their exceptional ice recrystallization inhibition capacity and high unfrozen water content. By designing customized freezing protocols based on their permeation characteristics, optimal cryoprotection was achieved using 5% NADES cooled at 5.28 °C/min in a precooled -80 °C environment. This integrated optimization approach yielded post-thaw cell viability comparable to that of conventional dimethyl sulfoxide (DMSO) while significantly reducing cytotoxicity. Our research not only validates the potential of NADES as highly efficient and biocompatible cryoprotectants, but it also establishes a straightforward and effective cryopreservation protocol system based on their fundamental biophysical characteristics.

Quantum dot light-emitting diodes (QLEDs) have emerged as strong contenders for next-generation display technologies. However, the commercialization of blue QLEDs has been severely hindered by the inherent wide band gap of blue quantum dots (QDs), which results in a high hole injection barrier and imbalanced carrier injection. Herein, we demonstrate high-efficiency and high-luminance blue QLEDs by engineering gradient core/shell ZnCdSe/ZnSe/ZnSeS/ZnS QDs with a ZnSe intermediate shell layer. The ZnSe interlayer not only effectively passivates surface defects but also facilitates balanced carrier injection. This strategy achieves a remarkable maximum luminance of 54,554 cd m-2 and an external quantum efficiency (EQE) of 20.6%, representing a significant advancement in device performance. This work provides a strategy for developing high-performance blue QLEDs.

The discovery of superconductivity with an onset temperature of-80 K in pressurized bilayer Ruddlesden-Popper La3Ni2O7-s has attracted much attention. Despite intense research, determination of the exact oxygen content and understanding of the relationship between superconductivity and oxygen content remain a big challenge. Here, we report a systematical study on the structure and physical properties of La3Ni2O7-s polycrystalline powders which were prepared using the sol-gel method at ambient pressure and then annealed under high oxygen pressure (pO2) or in ozone. The superconducting transition of La3Ni2O7-s at-80 K under high pressure is suppressed for high pO2 and ozone annealed samples. We attribute this to the combination of the following two reasons: (i) damage of the bilayer structure, as revealed by powder X-ray diffraction, scanning transmission electron microscopy and pair distribution function measurements, and (ii) hole overdoping due to the increasing of oxygen content. Our results reveal that the bilayer structure in La3Ni2O7-s is fragile and post-annealing under mild oxidization is suitable for maintaining the integrity of the bilayer structure and increasing oxygen content.

INTRODUCTION:Neisseria meningitidis, the primary pathogen of epidemic meningococcal meningitis, is a typical fastidious bacterium with stringent nutritional requirements and high environmental sensitivity, making routine preservation challenging. Current cryopreservation methods lack quantitative efficacy evaluation and suffer from low viability. OBJECTIVE:This study aimed to screen optimal permeable cryoprotectants (CPAs) for fastidious bacteria typified by N. meningitidis via cytotoxicity, cryopreservation viability, and ice crystal inhibition assays and elucidate the underlying protective mechanism. MATERIALS AND METHODS:Viable cell counting with ANOVA and Tukey's test assessed the cytotoxicity and post-cryopreservation survival of N. meningitidis treated with 10/15/20% glycerol and 5%, 10%, 15% dimethyl sulfoxide (DMSO), formamide (FMD), and propylene glycol (PG) in PBS/brain heart infusion (BHI) at 37°C for 15 min and frozen at -80°C for 48 hours. Differential scanning calorimetry (DSC) analyzed thermodynamic parameters of CPA solutions, and cryomicroscopy determined ice-inhibiting properties by observing ice crystal morphology and growth rate. RESULTS:Cytotoxicity assays showed N. meningitidis survival rates of 88.14%, 83.85%, and 81.62% in BHI broth with 5% DMSO, 5% FMD, and 5% PG, respectively. After 48 hours of -80°C cryopreservation, 5% DMSO exhibited the best protective effect in both PBS and BHI (p < 0.05), with survival rates of 64.93% and 63.11%. DSC analysis revealed decreased crystallization enthalpy (ΔHc) and melting temperature (Tm) of DMSO with increasing concentration in BHI. Cryomicroscopy confirmed 5% DMSO most effectively inhibited ice crystal growth (921.57 μm2 in PBS, 814.20 μm2 in BHI within 50 s). CONCLUSION:5% DMSO in BHI broth is the optimal permeable CPA for N. meningitidis and other fastidious bacteria. Its potential mechanism is that 5% DMSO balances bacterial osmotic pressure, alleviates solute and ice crystal damage, and balances ice inhibition with biocompatibility to enhance bacterial survival.

Rapid cooling in liquid nitrogen (LN) is critical for high-quality cryopreservation of biological samples, yet challenged by stable vapor film (Leidenfrost effect), severely impeding heat transfer. This study experimentally investigates the influence of low thermal conductivity polytetrafluoroethylene (PTFE) coatings with thicknesses of 20-300 mu m applied to aluminum vials containing cryoprotectants (CPAs) on cooling performance during LN quenching. The effects of the coating and the internal solution on cooling profiles, critical heat flux (CHF) and Leidenfrost temperature (TLFP) were analyzed. Vapor-liquid interface behavior on coated surfaces was experimentally visualized for the first time. Results show that as coating thickness increases, the quenching time first decreases and then increases, CHF first rises and then declines, while TLFP increases monotonically. Furthermore, for a given coating thickness, the TLFP of the VS55 solution consistently exceeds that of water. Visualization results reveal that during the film boiling, the average thickness of the stable vapor layer does not exceed 0.5 mm, whereas thicker coatings (e.g., 300 mu m) induce strong interfacial fluctuations at the onset of quenching and trigger the vapor film collapse in a propagating mode. The optimal thickness of 100-150 mu m minimizes timeaveraged thermal resistance by accelerating the transition to nucleate boiling, despite the fact that the coating increases the thermal resistance. This work advances the understanding of the "paradox of insulating layer" in cryopreservation, thereby facilitating the optimization of cooling protocols.

The development of blue/cyan-emitting phosphors which can be excited by near-ultraviolet light is remarkable for the backlighting field and the white light emitting diode (WLED) fields. Bi3+ ions as the emitters have the incomparable advantages over traditional rare earth ions: weak reabsorption effect, adjustable luminescence colors, low cost, etc. Effectively regulating the site selection of the Bi3+ activator is significant for the design of high-performance phosphors. In this work, a series of novel KBaYSi2O7:Bi3+,Zn2+ phosphors have been exploited which can be excited by near-ultraviolet light and exhibit excellent luminescent properties. A 3.7-fold enhancement of the narrow-band blue emission of KBaYSi2O7:0.2 %Bi3+ is achieved for the Bi3+/Zn2+ co-doped system. Meanwhile, the KBaYSi2O7:Bi3+,Zr4+ phosphors show a bright cyan emission band located at 489 nm to bridge the cyan gap and meet the demand for full-spectrum illumination, and a 1.7-fold enhancement of cyan emission is achieved by regulating the substitution position of Bi3+ in the matrix via the [ZrO4]4-anions. In addition to the superior luminescence properties, both KBaYSi2O7:Bi3+,Zn2+ and KBaYSi2O7:Bi3+,Zr4+ phosphors exhibit outstanding thermal stability, which retain 89.18 and 75.43 % of the initial emission intensity value with extremely high performing temperature of 443 K. Finally, the packaged WLED devices fabricated by the KBaYSi2O7:Bi3+,Zn2+ and KBaYSi2O7:Bi3+,Zr4+ phosphors, other commercial phosphors, and UV LED chips display dazzling warm white light with fascinating CIE coordinates and CCT. The result indicates that the as-prepared luminescent materials with outstanding luminescence performance and high thermal stability may be potentially applied in high-power LED devices and solid-state lighting.