SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4263-3
Monolayer black phosphorus (phosphorene) exhibits a direct bandgap and strong in-plane anisotropy, making it a promising candidate for near-infrared (NIR) optoelectronic devices. However, the precise modulation of its excitonic emission via anisotropic strain remains insufficiently understood, particularly regarding the contrasting strain responses of phosphorene versus transition metal dichalcogenides (TMDs). Here, we combine experimental characterization with tight-binding (TB) modeling to elucidate the strain-dependent bandgap evolution in phosphorene. Using a four-band TB model, we derive the bandgap at the Γ point as E_g^BP = 4t1 + 2t2 + 4t3 + 2t5, with hopping parameters t1 = -1.220 eV, t2 = 3.665 eV, t3 = -0.205 eV, t4 = -0.105 eV, and t5 = -0.055 eV. Under tensile strain along the zigzag (ZZ) direction, the interatomic distance associated with t1 increases, reducing the magnitude of |t1|. Since t1 is negative, the bandgap increases, contrary to the behavior of monolayer MoS2, where tensile strain decreases the bandgap due to positive hopping parameters t11, t22, and t12. This anisotropic strain response enables selective tuning of NIR exciton emission. Our findings provide a quantitative framework for strain engineering in phosphorene-based NIR devices, highlighting the critical role of hopping parameter signs in determining bandgap modulation.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202604016
River and lake health assessment is an important technical means to evaluate the health status of rivers and lakes, scientifically analyze river and lake problems, and strengthen the implementation of the river and lake head system. Based on the Guidelines for River and Lake Health Assessment (Trial) and the characteristics and actual basin conditions of the lower Yellow River in Henan, this study determined the river health evaluation index system for this reach. Through collection of basic data and special investigations and monitoring, the health status in 2020 was evaluated from four criteria layers: 'basin', 'water', biology, and social service function. The overall score was 83.4, corresponding to a 'healthy' grade. The four criteria layer scores were 73.7, 95.0, 62.1, and 95.5, respectively. The evaluation identified main problems including low aquatic biodiversity, suboptimal shoreline conditions, and pressure on water supply security. Corresponding governance and protection measures were proposed, such as strengthening ecological protection, improving river regulation works, enhancing shoreline management, and upgrading water diversion facilities. The results provide scientific basis for river health management and the implementation of the river chief system in the lower Yellow River.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3742-5
Nematic liquid crystal elastomers (NLCEs) exhibit excellent mechanical properties and diverse deformation modes, while cholesteric liquid crystal elastomers (CLCEs) as photonic crystals (PCs) possess superior optical performance and intelligent response characteristics. Combining these two elastomers into a monolithic material is a challenging yet promising endeavor. Here, we designed and synthesized a new diselenide-bonded molecule (DSeAc), whose lower bond energy between selenium atoms endows it with excellent bond exchange ability. Consequently, two LCE matrices containing DSeAc molecules can achieve seamless bonding under mild conditions via dynamic diselenide bond exchange. By integrating a CLCE film and an NLCE actuator into a monolithic film, we enable the integration of two functional components, whose functional characteristics can be tailored as required. This function block combination strategy offers a promising pathway for developing smart materials with complex functions, showing great potential in information storage, anti-counterfeiting, and biomimetics.