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High specific detectivity (D*) is one of the key performance metrics for near‐infrared (NIR) organic photodetectors (OPDs), which however is always limited by the high dark current density (Jd). Herein, high‐performance NIR‐OPDs with ultralow Jd are successfully achieved by developing new conjugated pyrrolic polysquaraines as photoactive materials. By changing the linkage sites of the carbazole bridge, two low‐bandgap pyrrolic polysquaraines, i.e., PSQ‐3,6‐Cz and PSQ‐2,7‐Cz, are prepared via a facile synthetic route, both showing strong absorption in the visible and NIR region (600–1000 nm), respectable hole mobility, and enhanced compatibility with the PC61BM acceptor. The fabricated polysquaraine‐based NIR‐OPDs deliver impressive Jd values as low as ≈2.0 × 10−11 A cm−2 in a photovoltaic mode, which to the best of the knowledge is among the lowest values for NIR‐OPDs so far, and thus enables a high shot‐noise‐limited specific detectivity (Dsh*) over 1013 Jones in 650–950 nm. With a more accurate noise spectral current measurement, the PSQ‐2,7‐Cz‐based OPDs show lower noise currents and better detection performance than the PSQ‐3,6‐Cz‐based OPDs, which is attributed to the lower energetic disorder degree and fewer traps of the former, both resulting in suppressed trap‐assisted recombination. [ABSTRACT FROM AUTHOR]

Squaraine dyes (SQs) are an important class of polymethine dyes with a unique reasonable‐stabilized zwitterionic structure, in which electrons are highly delocalized over the conjugated bridge. These dyes can not only be easily synthesized via a condensation, but also exhibit intense absorption and emission in the visible and near‐infrared region with excellent photochemical stability, making them attractive material candidates for many photoelectric and biomedical applications. Thus, in this review, after an introduction of SQs, the recent advances of SQs in the photovoltaic field are comprehensively summarized including dye‐sensitized solar cells, organic solar cells, and perovskite solar cells. Then, the important advances in the use of SQs as the biosensors, biological imaging, and photodynamic/photothermal therapy reagents in the biomedical field are also discussed. Finally, a summary and outlook will be provided with some new perspectives for the future design of SQs. [ABSTRACT FROM AUTHOR]

The grouting technique is an important method in underground engineering that prevents water seepage and reinforces fractured rock mass. In this research, ultrafine cement-based grouting material, including ultrafine cement (UC), ultrafine fly ash (UFA), polycarboxylate superplasticizer (SP), colloidal nanosilica (CNS), sodium sulfate solution (SS) and water, was developed. The flow time, viscosity, bleeding, setting time and uniaxial compressive strength of the UC-based slurry were measured by orthogonal experiments, and the optimal mix proportion of the UC-based slurry was obtained based on the Taguchi-Grey relational analysis method. Microstructure analysis of the UC-based slurry was conducted using scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests. The results showed that the Bingham model could provide a satisfactory description of the rheological properties of the UC-based slurry. The addition of CNS and SS could promote the hydration of the UC-based slurry and improve the microstructure of the hardened slurry, thereby increasing the strength of the hardened slurry. The optimum ratio for the UC-based slurry was water/solid (W/S) ratio of 1.0, and the contents of UFA, SP, CNS and SS by mass of UC were 40%, 0.2%, 4% and 4%, respectively. [ABSTRACT FROM AUTHOR]

Organic room temperature phosphorescence (ORTP) polymer materials have sparked considerable research interests in recent years, but their optical function is still limited for multi-mode optical imaging. Herein, a feasible and universal approach is proposed to endow ORTP polymer materials with periodic refractive index modulation functions by holographic patterning. The key to this approach is to design a two-stage stepwise crosslinking. Stage-1, with low crosslinking density (≤0.75 mol L -1 ), is phosphorescence-silent but can provide greater free volume for monomer diffusion and thus facilitate the patterning of refractive index modulated holograms via photopolymerization-induced phase separation. The dense crosslinking at stage-2 can turn on phosphorescence with the intensity rising by 144% when the crosslinking density increases from 3.77 to 4.12 mol L -1 . The enhanced phosphorescence is primarily ascribed to the increase of conformational distortion and spin-orbit coupling of organic phosphors based on theoretical calculations. Eventually, the first example is demonstrated of holographic plastic with the unique capability of independently displaying holographic andphosphorescent images. This work not only provides a novel paradigm to impart added optical functions to ORTP polymer materials but also paves the way for the development of high-security optical materials to combat counterfeiting., (© 2025 Wiley‐VCH GmbH.)