Bo Wang

Near‐infrared phosphor‐converted light‐emitting diodes (NIR pc‐LEDs) are highly attractive due to compact, low‐cost, and portable characteristics. Despite the discovery of several efficient and thermostable NIR garnet phosphors, the output power and photoelectric conversion efficiency of the fabricated NIR pc‐LEDs remain severely limited, hindering their practical deployment. Herein, we address this challenge by a single‐site substitution design of Ge ⁴⁺ for Si ⁴⁺ in a garnet host Y ₂ MgAl ₄ SiO ₁₂ (YMASi). The newly developed Y ₂ MgAl ₄ GeO ₁₂ (YMAGe):Cr ³⁺ phosphor demonstrates a substantially red‐shifted broadband NIR emission (90 nm shift, peaking at 809 nm) with an ultra‐broad full‐width at half maximum (FWHM) of 152 nm, along with good thermal stability (82%@423 K). Remarkably, this substitution simultaneously enhances the internal and external quantum efficiencies by factors of 1.8 and 2.1, respectively. Combining atomic‐resolution imaging with spectroscopic analysis, we unravel the origin of the spectral redshift and the underlying mechanism for the luminescent enhancement. Benefiting from these outstanding properties, driven by 100 mA, a prototype NIR light source fabricated with YMAGe:Cr ³⁺ achieves a high output power of 51.6 mW and photoelectric conversion efficiency of 22.7%, thereby demonstrating strong potential for multifunctional applications including night vision, biological imaging, non‐destructive testing, and plant growth lighting.

In recent years, Fe ³⁺ ‐activated near‐infrared (NIR) phosphors have made significant progress, but achieving broadband emission with high efficiency and high thermal stability remains a daunting challenge. A series of novel garnet‐type Gd ₃ Al ₄ GaO ₁₂ (GAGG) phosphors with Fe ³⁺ single‐doped and Fe ³⁺ /Yb ^{3 +} co‐doped were synthesized by the high‐temperature solid‐state method. Among them, GAGG: 0.01Fe ³⁺ exhibits intense broadband emission centered at 786 nm (650–1000 nm), lying predominantly in the NIR‐I region, upon 254 nm excitation, achieving a photoluminescence quantum yield (PLQY) as high as 82.6% and retaining 89% of its room‐temperature intensity at 420 K. Notably, introducing Yb ³⁺ establishes an efficient energy‐transfer pathway that extends the overall emission response into the NIR‐II region, with measurable emission reaching approximately 1150 nm, while boosting the PLQY to 90.1%. Leveraging the Stark level splitting and thermal population effects of Yb ³⁺ , the anomalous emission enhancement in the 900–1010 nm region compensates for Fe ³⁺ thermal quenching, enabling the GAGG: 0.01Fe ³⁺ , 0.15Yb ³⁺ phosphor to achieve zero thermal quenching with 100.1% intensity retention at 420 K. The results show that energy transfer engineering provides an effective strategy for developing high‐performance Fe ³⁺ ‐activated NIR materials with zero thermal quenching, offering promising applications in anti‐counterfeiting, night‐vision illumination, and non‐destructive testing.

Systematic strategies for modulating trap distributions through B-site cation engineering in metal halide phosphors remain elusive. Here, we employ density functional theory to guide the isovalent substitution of Cd2+ with Zn2+ in Cs3Cd2Cl7:Sb3+ afterglow phosphors. By leveraging the electronegativity difference and ionic radius mismatch between Zn2+ and Cd2+, we perturb the local bonding environment while preserving the [SbCl6]3– emission framework. Zn2+ incorporation modifies the local structural and electronic environments, while thermoluminescence spectroscopy reveals a broadened trap distribution. The optimized composition, Cs3Cd1.95Zn0.05Cl7:0.04Sb3+, exhibits prolonged afterglow exceeding 180 s-substantially longer than that of the undoped counterpart, while maintaining green self-trapped exciton (STE) emission centered at 518 nm. These engineered defects enable multimode optical readout via thermal stimulation, 980 nm photostimulation, and X-ray excitation. This work establishes a clear correlation between B-site cation identity and defect energetics, providing actionable design principles for next-generation optical storage materials.

Self‐assembly of lead halide perovskite nanocrystals into long‐range ordered superstructures can achieve reorganization of the morphological and chiroptical properties. Here, an efficient method is reported to achieve highly intrinsic chiral amplification in aqueous perovskite nanocrystals (PNCs) through freezing‐induced strong H‐bond driving self‐assembly into asymmetric superstructures. The aqueous PNCs with a high photoluminescence quantum yield (PLQY) of 92% are successfully synthesized by the water‐assisted strategy. Low temperature enhanced hydrogen bond network regulates the freezing‐induced self‐assembly of PNCs into asymmetric superstructures in aqueous solution, notably enhancing intrinsic circularly polarized luminescence (CPL) emission with over 200‐fold amplification of dissymmetry factor ( g _lum ), along with the g _lum of 4.1 × 10 ⁻³ at 253 K. The emission wavelength of CPL could be tunable by anion exchange in aqueous solution. Our finding offers a pioneering insight into efficiently amplifying intrinsic chiroptical response in low‐symmetry perovskites, opening a new avenue for the design of novel self‐assembly perovskite materials with superior optical properties and CPL character.

This study presents the synthesis of Mo ⁴⁺ ‐doped Cs ₄ ZnBi ₂ Cl ₁₂ double perovskite through a hydrothermal method, demonstrating efficient near‐infrared (NIR) emission at 1110 nm with a full width at half maximum (FWHM) of 45 nm. The emission originates from the d‐d transition of Mo ⁴⁺ ions within an octahedral crystal field. Structural analysis using powder X‐ray diffraction (PXRD) confirms the phase purity and lattice contraction as a result of Mo ⁴⁺ substitution at Bi ³⁺ sites, supported by X‐ray photoelectron spectroscopy (XPS) and elemental mapping. The material exhibits broad excitation compatibility (348–590 nm) and achieves a photoluminescence quantum yield (PLQY) of 45.3% with a microsecond‐scale lifetime of 6.78 μs. Thermal stability tests demonstrate sustained emission intensity (58% at 420 K) and resilience to prolonged heating or UV exposure. This work highlights Mo ⁴⁺ ‐doped Cs ₄ ZnBi ₂ Cl ₁₂ as a stable and efficient NIR emitter, advancing lead‐free perovskites for optoelectronic applications in bioimaging, agriculture, and sensing.

The development of efficient, thermally stable, and broadband near-infrared (NIR) phosphors is critical for next-generation smart devices yet remains challenged by limited quantum efficiency and spectral coverage in existing systems. Here, we introduce a breakthrough strategy via crystal field distortion engineering in zero-dimensional Cs₂ZnCl₄, achieving unprecedented Mo⁴⁺-activated broadband NIR emission centered at 960 nm with a fwhm ∼ 206 nm. Unlike conventional octahedral hosts, the tetrahedral Zn²⁺ site in Cs₂ZnCl₄ undergoes a distortion-driven transformation to an octahedral Mo⁴⁺ coordination upon doping, facilitated by Cs vacancies and Jahn-Teller effects. This unique structural reorganization enables a remarkable internal quantum efficiency of 78.7%. The material exhibits thermal stability and environmental robustness. Leveraging these properties, we fabricate NIR phosphor-converted LEDs (pc-LEDs) with a peak output power of 132 mW at 350 mA, demonstrating high-contrast imaging for fruit bruise detection and night vision. This work not only establishes a new paradigm for activator-centered lattice distortion to unlock efficient NIR luminescence but also expands the frontiers of 4d transition-metal-ion applications in optoelectronics.