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Dynamics of photoinduced species, as a key parameter for nanomaterials plays a significantly role in the performance of optoelectronic devices. In this work, the origin of broadband optical response for the emerging Ti3C2Tx MXene is revealed by transient spectroscopic analysis. From ultraviolet to infrared, the steady-state and transient optical responses present wavelength-related features. The carrier lifetime is found to change from femtosecond to nanosecond time scale dominated by various photoinduced species, i.e., carrier and surface plasmon. The unique optoelectronic character enables photodetection. This fundamental study on carrier, plasmon dynamics, and application in photodetection is helpful for exploring MXene-based optoelectronic devices.

High‐entropy (HE) MXenes represent a novel class of 2D materials within the MXene family, which are drawing widespread attention because of their diverse compositions and robust physicochemical properties. However, the exploration of HE‐MXenes in optoelectronic domains is relatively limited. This study unveils the rapid photoresponse and superior nonlinear optical (NLO) characteristics of HE‐MXene TiVCrMoC3Tx nanosheets (NSs) through comparison with ordinary MXene Ti3C2Tx NSs. Transient absorption spectroscopy reveals that the few‐layer TiVCrMoC3Tx NSs excel in photoelectrochemical‐type photodetectors with swift response properties. Additionally, the advantage of HE structures is further validated by NLO measurement system, which show that few‐layer TiVCrMoC3Tx NSs exhibit stronger saturable absorption than Ti3C2Tx NSs. First‐principles calculations based on the special quasi‐random structure method reveal that the transition behavior of HE‐MXene is similar to that of a semiconductor with direct bandgap, and this is ascribed to the main reason of strong photoelectric response. Taking advantage of the NLO properties of the TiVCrMoC3Tx NSs, all‐optical devices based on these NSs are applied to mode‐locked fiber lasers at 1, 1.5, and 2 µm wavebands, respectively. This investigation provides meaningful guidance for the future design and application of HE‐MXenes in high‐performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

Pathogenic microorganisms play a crucial role in the global disease burden due to their ability to cause various diseases and spread through multiple transmission routes. Immunity tests identify antigens related to these pathogens, thereby confirming past infections and monitoring the host's immune response. Traditional pathogen detection methods, including enzyme-linked immunosorbent assays (ELISAs) and chemiluminescent immunoassays (CLIAs), are often labor-intensive, slow, and reliant on sophisticated equipment and skilled personnel, which can be limiting in resource-poor settings. In contrast, the development of microfluidic technologies presents a promising alternative, offering automation, miniaturization, and cost efficiency. These advanced methods are poised to replace traditional assays by streamlining processes and enabling rapid, high-throughput immunity testing for pathogens. This review highlights the latest advancements in microfluidic systems designed for rapid and high-throughput immunity testing, incorporating immunosensors, single molecule arrays (Simoas), a lateral flow assay (LFA), and smartphone integration. It focuses on key pathogenic microorganisms such as SARS-CoV-2, influenza, and the ZIKA virus (ZIKV). Additionally, the review discusses the challenges, commercialization prospects, and future directions to advance microfluidic systems for infectious disease detection. [ABSTRACT FROM AUTHOR]

Providing higher precision Direction of Arrival (DOA) estimation has become a hot topic in the field of array signal processing for parameter estimation in recent years. However, when the physical aperture of the actual array is small, its aperture limitation means that even with super-resolution estimation algorithms, the achievable estimation precision is limited. This paper takes a novel approach by constructing an optimization algorithm using the covariance fitting criterion based on the array output's covariance matrix to fit and obtain the covariance matrix of a large aperture virtual array, thereby providing high-precision angular resolution through virtual aperture expansion. The covariance fitting expansion analysis and discussion are unfolded for both uniform linear arrays (ULAs) and sparse linear arrays (SLAs) under four different scenarios. Theoretical analysis and simulation experiments demonstrate that these methods can enhance the effective performance of angle estimation, especially in low signal-to-noise ratios (SNRs) and at small angular intervals by fitting virtual extended aperture data. [ABSTRACT FROM AUTHOR]

Within the fields of infectious disease diagnostics, microfluidic-based integrated technology systems have become a vital technology in enhancing the rapidity, accuracy, and portability of pathogen detection. These systems synergize microfluidic techniques with advanced molecular biology methods, including reverse transcription polymerase chain reaction (RT-PCR), loop-mediated isothermal amplification (LAMP), and clustered regularly interspaced short palindromic repeats (CRISPR), have been successfully used to identify a diverse array of pathogens, including COVID-19, Ebola, Zika, and dengue fever. This review outlines the advances in pathogen detection, attributing them to the integration of microfluidic technology with traditional molecular biology methods and smartphone- and paper-based diagnostic assays. The cutting-edge diagnostic technologies are of critical importance for disease prevention and epidemic surveillance. Looking ahead, research is expected to focus on increasing detection sensitivity, streamlining testing processes, reducing costs, and enhancing the capability for remote data sharing. These improvements aim to achieve broader coverage and quicker response mechanisms, thereby constructing a more robust defense for global public health security. [ABSTRACT FROM AUTHOR]

Due to the inherent high dark current of photoelectrochemical (PEC)‐type photodetectors (PDs), there is a tricky challenge to detect weak light. In this work, high‐quality Cd0.9Pb0.1Se quantum dots (CPS QDs) are prepared by thermal injection method, with horizontal size of 6.3 nm and thickness of 3.5 nm. The CPS QDs are directly utilized to construct the working electrode of PEC‐type PDs. The effects of experimental parameters on the photo‐response behavior are systematically studied, and optimized photocurrent density of 7.1 µA cm−2 and photo‐responsivity (Rph) of 2.75 mA·W−1 are achieved. Most importantly, the obvious photocurrent signals are observed under a light power density as low as 5.6 µW cm−2. For this interesting weak light detection, apparent Rph of 6.96 mA·W−1, detectivity of 1.2 × 109 Jones, and external quantum efficiency of 2.37% are achieved. Therefore, this work not only develops CPS QDs‐based PDs but also provides an example for PEC‐type PDs in weak light detection. [ABSTRACT FROM AUTHOR]