Key Takeaways & Executive Findings
- •• • The Rb2Ge4O9:0.002 Mn4+ fluorescent film achieves a relative sensitivity of 17.03% K−1 at 330 K in time-resolved thermometry, the highest within the physiological temperature range, enabling precise thermal monitoring in biomedical applications. • • A practical temperature resolution of 0.08 K at 325 K is demonstrated, allowing detection of minute temperature variations critical for microelectronics thermal management. • • The film encapsulated in PDMS exhibits enhanced chemical stability, addressing the degradation issue of bare phosphors in humid or reactive environments, thus extending operational lifetime. • • Temperature imaging of a 20 μm nickel circuit under varying currents reveals clear microstructure and temperature gradients, validating the technique for high-resolution thermal mapping in integrated circuits.
Abstract
Luminescent thermometry has become a research hotspot due to its high spatial resolution, fast response, and non-invasive nature. However, achieving high-performance temperature imaging requires both luminescent materials with high temperature sensitivity and efficient imaging methods, which remains a significant challenge. In this study, a series of pure-phase rubidium germanate phosphors doped with manganese were synthesized and encapsulated into polydimethylsiloxane (PDMS) films to improve chemical stability. The dramatic temperature-dependent luminescence behavior of Mn4+ in the Rb2Ge4O9 matrix provides reliable and efficient methods for temperature sensing. The high-sensitivity temperature sensing capability of the Rb2Ge4O9:0.002 Mn4+ fluorescent film has been confirmed, leveraging temperature-dependent emission intensity, luminescence decay lifetime, and time-resolved intensity ratio techniques. Notably, Rb2Ge4O9:Mn4+ fluorescent film exhibits a strikingly high relative sensitivity of 17.03% K−1 at 330 K in the time-resolved thermometry scheme, which is the highest relative temperature sensitivity within the physiological temperature range known to us. High-performance temperature imaging of the fluorescent film is achieved through the time-resolved intensity ratio strategy with a best practical temperature resolution of 0.08 K at 325 K. Furthermore, the temperature images of an operating nickel circuit with a line width of 20 μm under different working currents were recorded, showing a clear circuit microstructure and temperature gradient. These findings pave a novel path for realizing high-performance temperature imaging.
1. Introduction
Luminescent thermometry has attracted significant attention for non-contact temperature sensing due to its high spatial resolution and fast response. However, conventional approaches often rely on rare-earth ions with shielded 4f transitions, which exhibit limited temperature sensitivity. Transition metal ions, particularly Mn4+, with unshielded 3d electrons, are more susceptible to thermal variations, yet their application has been hindered by the scarcity of suitable host matrices that provide octahedral coordination and efficient red emission. Germanates are promising hosts due to ionic radius and charge matching, but the rarity of octahedral Ge4+ sites restricts material selection.
This work addresses the bottleneck by synthesizing Mn4+-doped Rb2Ge4O9, which provides the necessary octahedral environment. The material is encapsulated in PDMS to enhance chemical stability, and a time-resolved intensity ratio method is employed to achieve high sensitivity and imaging capability. This approach overcomes the limitations of intensity-based methods that suffer from probe concentration and excitation power fluctuations, offering a robust solution for high-performance thermal imaging in demanding applications.
Loading authentic research manuscript (Pages 1–5)...
Qian Zhang, Zhicheng Liao, Liting Qiu, Min Yin, Yonghu Chen, Xiantao Wei (2026). High-performance temperature imaging of Mn4+ doped Rb2Ge4O9 film using the time-resolved intensity ratio method. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-025-3662-4
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the maximum relative sensitivity and at what temperature is it achieved?
The maximum relative sensitivity is 17.03% K−1 at 330 K, as measured in the time-resolved thermometry scheme.
How does the time-resolved intensity ratio method improve temperature resolution compared to conventional intensity-based methods?
The time-resolved intensity ratio method achieves a practical temperature resolution of 0.08 K at 325 K, which is superior to intensity-based methods that are affected by excitation fluctuations and probe concentration.
What is the role of PDMS encapsulation in the performance of the phosphor?
PDMS encapsulation enhances the chemical stability of the Rb2Ge4O9:Mn4+ phosphor, preventing degradation in humid or reactive environments, thereby maintaining its luminescent properties over extended use.
Can this technique be applied to microelectronic thermal imaging?
Yes, the technique successfully imaged a 20 μm nickel circuit under different currents, revealing clear temperature gradients, demonstrating its capability for high-resolution thermal mapping in microelectronics.
What are the potential limitations of this material for industrial deployment?
Potential limitations include the need for precise synthesis to maintain pure phase and the cost of germanium precursors. However, the high sensitivity and stability may offset these costs in specialized applications.
Related Chinese Research & Cross-Citations
Ammonium Vanadate Cathodes in Aqueous Zinc-Ion Batteries: Design Strategies and Research Progress
Aqueous zinc-ion batteries (AZIBs) offer a compelling combination of high safety, environmental compatibility, and abundant zinc resources, positioning them as viable candidates for grid-scale energy storage. Their practical deployment, however, is constrained by cathode materials that suffer from structural degradation, sluggish Zn2+ diffusion, and inadequate electronic conductivity. Ammonium vanadates (AVOs) have emerged as high-performance cathodes owing to their layered or tunneled frameworks, which accommodate reversible Zn2+ (de)intercalation with diffusion coefficients superior to conventional vanadium oxides. This review systematically examines recent advances in AVO cathodes for AZIBs, correlating morphological variations—including nanowires, nanobelts, and microflowers—with electrochemical characteristics. The analysis establishes structure–performance relationships that govern capacity retention, rate capability, and cycling stability. Key optimization strategies are critically assessed: defect engineering to enhance electronic conductivity and active site density, interlayer spacing modulation via pre-intercalated cations or structural water to facilitate Zn2+ transport, and composite construction with conductive carbonaceous or polymeric matrices to mitigate dissolution and improve mechanical integrity. Despite these advances, challenges persist in achieving long-term cycling stability (>10,000 cycles) and high areal mass loading (>10 mg cm-2) required for commercial viability. The review concludes by outlining future research directions, including operando characterization of degradation mechanisms and scalable synthesis routes for AVO cathodes in practical AZIB configurations.
Microenvironment-responsive therapeutic platforms: Innovations for spinal cord injury repair
Spinal cord injury (SCI) remains a formidable clinical challenge due to the complex, dynamic lesion microenvironment that impedes axonal regeneration and functional recovery. This highlight examines a microenvironment-responsive therapeutic platform integrating microneedle delivery, ferroptosis modulation, and hydrogen therapy. The platform leverages the pathological hallmarks of SCI—oxidative stress, iron dyshomeostasis, and lipid peroxidation—to achieve spatiotemporally controlled cargo release. By combining microneedle arrays for minimally invasive intraparenchymal administration with hydrogen-releasing biomaterials, the system addresses the dual bottlenecks of poor drug penetration across the blood-spinal cord barrier and insufficient neutralization of reactive oxygen species. Ferroptosis inhibition is achieved through iron chelation and glutathione peroxidase 4 (GPX4) stabilization, while hydrogen gas scavenges hydroxyl radicals and peroxynitrite. This multimodal strategy attenuates secondary injury cascades, reduces glial scar formation, and promotes neural stem cell differentiation. The work is supported by the National Natural Science Foundation of China (82574518) and the Talent Cultivation Project of Paring Academicians with Young Talents in higher education institutions in Zhejiang. The authors declare no conflict of interest. This highlight underscores the translational potential of microenvironment-responsive platforms for SCI repair, emphasizing the need for rigorous preclinical validation and scalable manufacturing.
Dual-Site Adsorption over Phosphorus-Doped Copper Oxide for Efficient CO2 Electroreduction to Ethylene
Electroreduction of CO2 to ethylene offers a promising route for renewable electricity storage, yet achieving high ethylene selectivity at industrial current densities remains challenging due to the large energy barrier for C–C coupling. Here, we report a “MOF-assisted in situ doping” strategy to introduce the oxophilic nonmetal phosphorus (P) into the copper oxide (CuO) lattice, constructing a localized Cu–P dual-site adsorption configuration for the key *OCCHO intermediate. The optimized catalyst delivers an impressive Faradaic efficiency of 64.6% for ethylene with a partial current density of 646 mA cm-2. Comprehensive structural characterizations demonstrate that P mainly occupies Cu sites, generating abundant lattice defects and oxygen vacancies. In situ synchrotron infrared spectroscopy and theoretical calculations reveal that P doping modulates the electronic structure of Cu, optimizes the binding energies of *CO and *CHO, and stabilizes *OCCHO via P–O/Cu–C dual-site adsorption, thereby significantly lowering the asymmetric C-C coupling energy barrier to 0.74 eV. This work highlights a dual-site microenvironment regulation strategy for CO2-to-ethylene electroreduction.
Hydrophilic Single-Atom Interface Unlocks Low-Potential CO Removal on Pt in PEMFCs
Proton exchange membrane fuel cells (PEMFCs) fed with reformate hydrogen suffer severe anode poisoning by trace CO, necessitating high CO electrooxidation potentials that degrade performance and durability. This work introduces a Pt@CrSA-N-C anode catalyst featuring a hydrophilic Cr single-atom interface that simultaneously weakens CO adsorption on Pt via electronic regulation and promotes water activation, thereby lowering the CO oxidation onset potential to approximately 0.13 V vs. RHE. The onset potential was determined by two independent methods: the first potential at which the background-corrected current exceeds 0 mA cm-2 during CO oxidation reaction tests in a three-electrode system, and the potential at which the forward scan current exceeds the N2 background current in CO-stripping voltammetry. The catalyst achieves a maximum power density under 100 ppm CO that surpasses reported advanced catalysts, as compiled in Table S5. Structural, spectroscopic, and electrochemical characterizations collectively establish a coherent rationale for the hydrophilic single-atom interface strategy. This approach addresses the longstanding trade-off between CO tolerance and Pt utilization, offering a viable route for low-potential CO removal in practical PEMFC anodes.
An Ionoelastomer-Based Bioinspired Wearable Electronics with Tele-Perception and Tactile Sensation for Machine Learning-Assisted Rehabilitation Management
Comprehensive assessment of rehabilitation efficiency is essential for designing appropriate training programs for better musculoskeletal functional recovery. Existing contact-receptor-dependent rehabilitation assessment systems mostly focus on assessing the restoration of muscle function by evaluating grip strength or joint flexion angle; however, parameters reflecting neuromuscular synergistic function are always overlooked. Herein, we develop an ionoelastomer-based soft artificial electroreceptor (SAER) that integrates tele-perception and tactile sensation to track the rehabilitation process, collecting signals related to approaching speed and grip strength sequentially. The SAER uses polyurethane ionoelastomer incorporated with quasi-solid conductive salt as the electric field receptor, and is integrated on a rehabilitation-training ball after assembly to establish an untethered detection device; this enables the remote capture of hand approaching parameter within a 9 cm range, followed by the quantification of grip strength when contacting and grasping. Furthermore, a data-driven assessment system is established by integrating machine learning, which accurately classifies rehabilitation efficiency into six levels; it supports for rehabilitation evaluation and training programs adjustment. Overall, the SAER-based rehabilitation management system establishes a paradigm that synergistically evaluating parameters corresponding to neuromuscular functional restoration and holds strong potential for home-based active rehabilitation for minimizing dependence on frequent clinical supervision.
Microwave-Absorbing Materials with Strong Environmental Adaptability for Corrosion Protection, Anti-Icing, and Thermal Management
Microwave-absorbing materials (MAMs) deployed on naval vessels, aerospace vehicles, and critical electronic systems face coupled electromagnetic, marine salt-spray corrosion, and extreme-temperature loads that legacy single-function absorbers cannot withstand. This review consolidates progress on three environmentally adaptive MAM classes: corrosion-protective, anti-icing, and thermal-management absorbers. The electromagnetic loss and impedance-matching fundamentals are first established, then the synergistic mechanisms, design strategies, and characterization protocols for each class are examined against representative material systems and their measured performance. The analysis identifies a shared design logic—multiscale hierarchical architecture, interfacial polarization engineering, and multifunctional phase integration—while distinguishing the divergent protection mechanisms: barrier and passivation effects for corrosion, surface-energy and latent-heat regulation for anti-icing, and phonon–electron transport decoupling for thermal management. Persistent bottlenecks include the trade-off between impedance matching and protective-layer density, the absence of standardized coupled-field test protocols, and the scarcity of long-term salt-spray and thermal-cycling durability data. Future directions are delineated: intelligent self-adaptive absorbers, multiphysics-coupled simulation frameworks, and environmentally benign multifunctional integration. The review provides a theoretical and technical basis for the design, construction, and engineering scale-up of next-generation high-performance absorbers for aerospace, electronic, and marine equipment.