SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4202-3
Carbon dots (CDs) with absorption in the second near-infrared window (NIR-II, 900-1700 nm) hold promise for tumor theranostics, yet existing synthesis methods often involve complex procedures, harsh conditions, or lack precise control. Here we report a 'self-photooxidation-restructuring' strategy that enables structural reorganization of the carbon core in CDs, achieving a significant redshift of absorption into the NIR-II region. Under ultraviolet (UV) light irradiation, the precursor (B-CDs, absorption in UV region) generates singlet oxygen, which self-oxidizes aldehyde groups and the carbon skeleton of B-CDs to stronger electron-withdrawing carboxyl groups and carbon radicals, respectively. These processes facilitate the formation of new C=C bonds between isolated aromatic domains, thereby transforming B-CDs into novel CDs (N-CDs) characterized by enhanced donor-acceptor interactions and a redshift in absorption toward the NIR-II window. Various experimental data, including high-resolution XPS, FTIR, NMR, EPR, have proved the proposed formation mechanism. The novel N-CDs afforded a high photothermal conversion efficiency of up to 71.33%, which enabled 1064 nm laser-activated photoacoustic imaging (PAI)-guided photothermal therapy (PTT) in tumors. This work opens a new avenue for the synthesis and modulation of CDs in the NIR-II region.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3920-1
Lead-free halide perovskites are promising scintillators due to strong X-ray attenuation and high internal quantum efficiency (IQE), but their application is hindered by moisture sensitivity. Here, CsSrCl3:Eu2+ nanocrystals were grown in situ in a specially designed inorganic glass matrix. By employing [PO4]-modification and controlled crystallization, a transparent CsSrCl3:Eu2+ glass-ceramic (GC) scintillator was obtained, combining high crystallinity (15.9%) with excellent optical transparency (85.3% at 432 nm). The GC exhibits outstanding photoluminescence (PL) performance, including a high IQE of 87.6% and superior thermal stability (74% intensity retention at 493 K relative to 303 K). Benefiting from the robust glass matrix, the GC retains 99% of its initial PL intensity after 14 days of water immersion. Under X-ray excitation, it shows blue X-ray excited luminescence (XEL), with peak and integrated intensities reaching 117% and 25.1% of those of Bi4Ge3O12 crystal, respectively. The scintillator achieves a high spatial resolution of 20 lp mm−1 and an X-ray detection limit of 3.7 μGy s−1. Furthermore, it demonstrates exceptional operational stability in humid environments, maintaining clear X-ray image contrast even after 48 h of water submersion. This study provides an effective strategy for stabilizing hygroscopic halide scintillators in a durable [PO4]-modified fluoroaluminate glass matrix and demonstrates the potential of CsSrCl3:Eu2+ GC for high-resolution and stable X-ray imaging.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3551-5
Flexible photonic crystal (PC) materials exhibit exceptional optical properties but suffer structural degradation under repeated mechanical stress, leading to photonic band gap impairment and limited sustainability. This study introduces a self-healing thermoplastic polyurethane (STPU) with an inverse-opal PC structure, inspired by natural structural coloration and self-healing mechanisms. Synergistic dynamic covalent disulfide bonds and hydrogen bonds enable reversible mechanical adjustment, yielding a tensile strength of 26.76 MPa and elongation at break of 2000%. The inverse opal structure facilitates reversible color transitions in response to solvents (water, ethanol) and mechanical strain (0–70%) via lattice spacing modulation. Incorporating an interpenetrating network of polyacrylamide hydrogel and carbon nanotubes enhances strain sensitivity and structural color stability. The material demonstrates broad potential in flexible sensors, adaptive optical devices, bioinspired robotic skins, and dynamic anti-counterfeiting encryption, overcoming traditional PC limitations such as high fragility and single functionality. This strategy advances durable intelligent sensing materials with enhanced environmental adaptability and multifunctional integration.