ABSTRACT Achieving wide‐coverage near‐infrared (NIR) luminescence spanning from NIR‐I to NIR‐II regions in Cr 3+ ‐sensitized rare‐earth‐ion (RE 3+ ) phosphor systems without sacrificing the Cr 3+ emission intensity remains a significant challenge. Herein, a novel double‐perovskite‐structured Cs 2 RbScF 6 host with large interionic separation was first discovered, which enables successful full substitution of Sc 3+ by Cr 3+ without concentration quenching. The resulting Cs 2 RbCrF 6 phosphor exhibits broadband NIR emission centered at 775 nm with a full width at half maximum of ∼118 nm, and high internal/external quantum efficiencies of 84.2%/32.1%. More importantly, this Cr‐rich host serves as an effective sensitizing platform for RE 3+ ions (i.e., Yb 3+ , Nd 3+ , Er 3+ ), extending the spectral coverage from 650 to 1600 nm via efficient Cr 3+ →RE 3+ energy transfer, while remarkably retaining substantial Cr 3+ emission intensity. This balanced coexistence of intense broadband Cr 3+ and multiple RE 3+ characteristic emissions enables a genuinely wide‐coverage NIR luminescence profile spanning 650–1600 nm. Finally, a prototype NIR phosphor‐converted LEDs device was fabricated and innovatively demonstrated practical utility for quantitatively monitoring various RE 3+ concentrations and detecting aqueous‐phase entrainment in the organic phase during solvent extraction. This work provides a rational design strategy for developing high‐efficiency wide‐coverage NIR phosphors and offers a new broadband NIR light source for real‐time monitoring of RE solvent extraction processes.
ABSTRACT The development of highly efficient and stable hydrogen evolution reaction (HER) electrocatalysts is crucial for the large‐scale production of clean hydrogen energy. Herein, PtRu composite nanomaterials confined to TiO 2 nanotube arrays were prepared by anodic oxidation‐hydrothermal method, which integrated multifunctional active sites such as single‐atom Pt, single‐atom Ru, Pt clusters; Through synergistic effects, the material maintains remarkable HER activity with very low noble‐metal loadings, and significantly surpasses commercial Pt/C and PtRu/C catalysts in diverse applications. In situ infrared and Raman spectroscopy observed the interfacial adsorption of H 2 O and [H] formation on Pt/Ru sites, unveiling their co‑participation, while DFT calculations further clarified the synergy of multiple active sites in H 2 O adsorption, activation, dissociation, and [H] production. Meanwhile, by creating a state of enrichment in the hollow tubes and wall pores, the hollow structure promotes the active sites exposure and confined metal sites, while the abundant pores on the nanotube walls provide dynamic fluid channels for the timely release of hydrogen, forming gas‐liquid separation channels with the electrolyte and promoting matter exchange. This study combines surface‑rich supports and multi‑functional sites to boost noble metal utilization, and establishes gas‑liquid separation channels to promotes matter exchange, offering a strategy for ultra‑low noble metal HER electrocatalysts.
ABSTRACT Lithium‐metal all‐solid‐state batteries offer a pathway toward high‐specific‐energy storage but remain limited by instability at the solid‐state electrolyte (SSE)/Li interface. Fluorinated chloride solid electrolytes exhibit improved kinetic stability toward Li metal at low current densities (≤0.2 mA cm −2 ), but become increasingly susceptible to electron injection at high current densities (≥1 mA cm −2 ), leading to sustained reductive decomposition and interfacial degradation. Here, we develop LiCl‑deficient Li 3‑x InCl 5.2‑x F 0.8 solid electrolytes to regulate interfacial electron transport. LiCl deficiency generates Li vacancies preferentially at 4 g sites and lowers the barrier for In migration into these vacancies, thereby forming In‐on‐Li antisites. These antisite‐centered defect environments serve as electron‐localization centers that trap injected electrons, suppress long‐range electronic transport, and inhibit the reduction of In 3+ to metallic In. This electron‐localization mechanism promotes a self‐passivating interphase and markedly improves high‐current‐density compatibility with Li metal. The optimized Li 2.76 InCl 4.96 F 0.8 composition exhibits an ionic conductivity of 1.24 mS cm −1 , stable Li plating/stripping at 1.0–1.5 mA cm −2 , and durable full‐cell cycling with LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cathodes at 1 mA cm −2 . These findings establish LiCl‐deficiency‐induced electron localization as an atomic‐scale electronic regulation strategy for enabling high‐current‐density compatibility between chloride solid electrolytes and Li‐metal anodes, thereby advancing the development of high‐specific‐energy all‐solid‐state lithium‐metal batteries.
ABSTRACT Hydrogen sensors play a pivotal role in tomorrow's hydrogen economy, yet today's sensors cannot fulfill all needs. We rationally design resistive thin‐film hydrogen sensors based on tantalum alloys. The heart of the sensor is a tantalum‐based layer, that gradually absorbs hydrogen when exposed to hydrogen, which in turn results in a measurable change of the resistance. In situ x‐ray diffraction and x‐ray and neutron reflectometry show that nanoconfinement efficiently suppresses unwanted phase transitions present in bulk when the material is exposed to hydrogen and enables completely elastic expansion, yielding a stable, hysteresis‐free and long‐life sensor. Additionally, alloying is used to maximize the sensitivity of the sensor. The resulting sensor, combining a 5 nm sensing layer with a 4 nm adhesion layer, a 5 nm capping layer, and polymer protective layers, enables a low‐cost, reversible hydrogen sensor with a hysteresis‐free sensing range from ppb to 100% in anaerobic conditions at room temperature and sub‐second response‐times.
ABSTRACT Modulating intrinsic molecular dipoles via donor–acceptor ( D – A ) skeleton engineering is an effective strategy for promoting charge dynamics in organic photocatalysts. However, conventional intermolecular D – A covalent organic frameworks (COFs) suffer from weak electronic coupling and uncontrollable dipole strength, with elusive structure–dipole–activity relationships. Herein, two isoreticular imine‐linked COFs are fabricated via pre‐embedded intramolecular D – A engineering. Unlike conventional intermolecular D – A COFs assembled from independent donor and acceptor monomers, the donor and acceptor units are covalently locked within a single C 3 ‐symmetric building block. Periodic integration of the pre‐embedded intramolecular D – A motif endows CR‐COF‐7 with improved crystalline ordering, accessible porosity, and enhanced framework polarization. Periodic calculations reveal an electrostatic potential step of 0.220 eV across the CR‐COF‐7 layer and a 0.76 eV reduction in work function, favoring electron transfer to platinum (Pt). Complementary spectroscopic and photoelectrochemical measurements support the notion of facilitated exciton conversion and enhanced utilization of photogenerated charges. Consequently, CR‐COF‐7 exhibits a photocatalytic hydrogen evolution rate of 12.09 mmol g −1 h −1 , approximately 150‐fold higher than that of CR‐COF‐8, and outperforms an intermolecular D – A COF control. This work reveals the dipole regulation mechanism of intramolecular D – A modification and provides a general design principle for high‐efficiency COF‐based solar photocatalysts.
