SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4502-1
Near-infrared-II (NIR-II, 1000-1700 nm) luminescent materials are pivotal for deep-tissue bioimaging and optical communication, yet their performance is often limited by low quantum yields and thermal quenching. Here, we report a thermal-enhanced NIR-II luminescence in Sb3+/Er3+ co-doped Cs3GdCl6 microcrystals synthesized via a modified Bridgman method. Under ultraviolet excitation, the co-doped microcrystals exhibit intense NIR-II emission centered at 1532 nm corresponding to Er3+: 4I13/2 → 4I15/2 transition, with a maximum relative sensitivity of 1.2% K−1 at 303 K. Notably, the integrated NIR-II emission intensity increases by 2.3-fold from 298 K to 373 K, demonstrating anomalous thermal enhancement. This behavior is attributed to the thermally activated energy transfer from Sb3+ sensitizers to Er3+ activators, as confirmed by temperature-dependent photoluminescence spectra and decay kinetics. The energy transfer efficiency reaches 86% at room temperature and further improves with rising temperature. The microcrystals also show excellent photostability, retaining 95% of initial intensity after 120 min continuous UV irradiation. Furthermore, we demonstrate a proof-of-concept wireless optical communication link using the microcrystals as a NIR-II phosphor, achieving a signal-to-noise ratio of 30 dB at 400 Hz modulation frequency. These findings provide a new strategy for designing thermal-enhanced NIR-II luminescent materials and expand their potential in temperature sensing and optical communication.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4376-3
Single-molecule localization microscopy (SMLM) surpasses the diffraction limit to achieve molecular-scale resolution, but conventional probes suffer from photobleaching, limiting imaging duration. In a recent Nature Photonics article, Ren and co-workers introduced spontaneous photoblinking upconversion microscopy (SPUM) using Yb3+/Ho3+ co-doped core–shell–shell upconversion nanoparticles (UCNPs, NaYF4@NaYb/HoF4@NaLuF4). These UCNPs exhibit exceptional photostability and persistent, reversible blinking under 976 nm continuous-wave excitation, with negligible photodegradation. The blinking mechanism involves a Yb3+ multiphoton process coupled with defect-mediated energy trapping, switching the UCNPs between emissive (on) and non-emissive (off) states. Kinetic analysis revealed single-exponential bright-state dwell times and biexponential dark-state dwell times, indicating one decay pathway into a non-emissive state and two recovery pathways. In live-cell imaging, synchronized transport of UCNPs maintained constant interparticle distance and near-unity positional correlation. In fixed cells, Fourier ring correlation (FRC) resolution reached 30 nm, confirming sub-50 nm performance in biological specimens. This work provides an unprecedented combination of low duty cycle and photostability, establishing a foundation for non-photobleaching luminescent nanomaterials in long-term super-resolution imaging and nanoscale tracking.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3556-6
Photon avalanche (PA) is a nonlinear optical phenomenon characterized by steep upconversion emission growth with excitation power. Since the first demonstration of PA on nanoscale and at room temperature in 2021, PA luminescence of lanthanides has attracted considerable attention in nano- and bio-photonics. However, PA nanoparticles (NPs) remain restricted to a limited range of material systems and lanthanide ions, facing challenges including inadequate nonlinearity (N), high excitation threshold (P_th), and deficient chromaticity. In a recent publication in Nature Photonics, Dong and co-workers reported a new class of PA nanosystem based on Ho3+-doped fluoride NPs, which afforded tunable PA chromaticity for multicolor sub-diffraction imaging. Unlike conventional PA systems reliant on a single reservoir level, this study introduced a novel 'parallel PA' (PPA) mechanism leveraging the dual long-lived intermediate reservoir levels (5I7 and 5I6) of Ho3+, facilitating simultaneous operation of two PA loops to generate multicolor emissions. Under 965 nm continuous-wave excitation, the PPA of Ho3+ produced simultaneous red-green-blue emissions with large N (>20). Differential rate equation modelling identified all PA signatures, including clear P_th, S-shaped curves, extremely high sigma_ESA/sigma_GSA ratio of ~75000, and volcano-shaped rise time. The engineered NaGdF4:10%Ho@NaYF4 core/shell PA NPs (~19.6 nm) exhibited remarkably high N of 17–22 with mild P_th of ~22 kW cm−2 and fast response time of 343–371 ms. By screening host lattices and introducing co-dopants, PA chromaticity was precisely tailored, demonstrating unparalleled emission tunability for multicolor super-resolution imaging.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3956-0
Chiral organic-inorganic hybrid metal halides (OIHMHs) are multifunctional materials with structural diversity and chiroptical properties. However, current chiral OIHMHs predominantly exhibit circularly polarized luminescence (CPL) in the visible spectrum, while ultraviolet and near-infrared (NIR) CPL remains challenging. Here, we report lead-free chiral zero-dimensional (0D) OIHMHs, (R/S-DACH)2In2Br10:Sb3+/Yb3+ (DACH = 1,2-diaminocyclohexane), featuring spectrally tunable CPL emissions covering visible to NIR regions. Single-crystal X-ray diffraction, circular dichroism, and CPL spectroscopy revealed that robust hydrogen-bonding interactions between organic cations and inorganic emitters are crucial for chirality expression. Sb3+-doped (R/S-DACH)2In2Br10 single crystals exhibited intense broadband emission at 644 nm from the 3P1 to 1S0 transition of Sb3+, achieving a record photoluminescence quantum yield (PLQY) of 49.9% (two orders of magnitude higher than pristine crystals) and a luminescence dissymmetry factor (glum) of ±7.1×10−3. Notably, Sb3+/Yb3+ co-doped crystals simultaneously generated dual-band CPL at 644 nm (glum = ±2.1×10−2) and 994 nm (glum = ±6.8×10−3), representing an important example of NIR-CPL in OIHMHs. An LED device based on (R-DACH)2In2Br10:2.7%Sb3+ exhibited bright orange emission with a color-rendering index of 78.4 and excellent spectral and operational stabilities. These findings establish a design strategy for broadband CPL and expand applications of chiral metal halides in advanced optoelectronics.