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2D organic crystals play a unique role in photodetection owing to their tunable detection wavelength, low manufacturing cost, compatibility with lightweight, and controllable synthesis. However, their detection wavelength range mainly encompasses the visible (Vis) and near‐infrared (NIR) spectra. Herein, 2D erucamide crystals are synthesized using nitrogen gas and methanol as raw materials without catalysts at room temperature under atmospheric pressure via laser processing. The synthesized 2D erucamide is demonstrated to be a promising broad bandgap organic semiconductor material. A UV photodetector made of 2D erucamide exhibited a responsivity as high as 145 mA W−1, a millisecond‐level response speed, and an excellent detectivity of 4.96 × 109 Jones. Furthermore, the synthesized erucamide showed an excellent UV–vis suppression ratio (R254 nm/R532 nm) of 59. The synthesis mechanism of erucamide via laser bubbling in liquids is proposed. Thermodynamically, the high temperature of the bubbles is beneficial for nitrogen and methanol decomposition. Kinetically, rapid bubble quenching facilitates final product formation. This accomplishment represented the pioneering utilization of lasers in converting nitrogen gas into organic compounds while introducing 2D erucamide into the realm of organic UV photodetectors. [ABSTRACT FROM AUTHOR]

Ultrabroadband and polarization‐sensitive imaging are essential for pioneering advancements in intelligent technology, offering a pivotal pathway to multidimensional information extraction. However, the dearth of appropriate photosensitive semiconductors in the infrared region and the lack of suitably efficient device architecture for the separation and collection of photocarriers significantly impede the development of ultra‐broadband and polarization‐sensitive photodetectors. To address these challenges, a sandwiched Ta2NiSe5/MoTe2/Graphene heterostructure device is engineered. In this device, efficient and polarization‐sensitive photocarriers are generated in the top Ta2NiSe5 layer, rapidly separated through the middle MoTe2 layer, and effectively collected by the bottom graphene layer. As a result, the developed photodetector exhibits an ultra‐broadband and polarization‐sensitive photoresponse that extends from visible light (520 nm) to short‐wave infrared (2200 nm). At 2200 nm, the device displays a notable responsivity of 5.79 A W−1, a specific detectivity of 1010 Jones, and an anisotropic ratio of 1.44. Furthermore, this device successfully demonstrates high‐resolution ultra‐broadband and polarized light imaging capabilities. This study thus presents an intriguing blueprint for the development of advanced 2D imaging platforms for future‐generation intelligent systems. [ABSTRACT FROM AUTHOR]

Zero-dimensional (0D) organic–inorganic metal halide hybrids (MHHs) are considered promising luminescent materials due to their unique "host–guest" structure and tunable emission spectrum. Herein, we successfully prepared Sb3+-doped 0D (CH6N3)3BiCl6 single crystals using an evaporation solvent method. The introduction of Sb3+ results in a bright orange emission with a center wavelength of 610 nm. On increasing the Sb3+ doping level to 20%, the doped sample achieves the highest photoluminescence quantum yield (PLQY) of 53%, attributed to the formation of self-trapped excitons (STEs) induced by the strong interaction between electrons and the crystal lattice. Interestingly, Sb3+-doped (CH6N3)3BiCl6 exhibits rapidly reversible ethanol-responsive luminescence transition between orange and yellow emissions. This class of 0D MHHs exhibits high sensitivity and repeatability as a fluorescent probe for ethanol detection, demonstrating significant potential in environmental monitoring and ethanol detection applications. [ABSTRACT FROM AUTHOR]

High‐speed and sensitive UV–Vis photodetectors have been constructed based on a typical 1D van der Waals material, antimony sulfide (Sb2S3). Impressively, the Sb2S3 nanowire photodetector demonstrates pronounced photosensitivity exhibiting a remarkable on/off ratio of ≈2800 under a power density of 318 mW cm−2. In addition, a high responsivity, an outstanding detectivity, and a short response/recovery time of 270 A W−1, 4.37 × 1013 Jones, and 10/12 ms are achieved. The competitive photosensitivity is associated with the intrinsic Mie resonance of the Sb2S3 nanowire, which is conducive to enhancing the coupling of the Sb2S3 photosensitive channel with incident light. By virtue of the unique 1D structural nature in both intrinsic and extrinsic perspectives, the Sb2S3 nanowire photodetectors manifest distinct polarization‐discriminating photoresponse with the optimal dichroic ratio reaching ≈7.2. Moreover, the Sb2S3 nanowire photodetectors demonstrate stable photoresponse from room temperature to 160 °C, and these nanodevices are durable against long‐term high‐temperature heating treatment at up to 300 °C. Taking advantage of the excellent thermal robustness, high‐temperature‐proof optoelectronic imaging and dual‐channel optical communication applications are demonstrated based on low‐dimensional van der Waals materials. On the whole, this study provides a new option for an advanced multifunctional optoelectronic system in extreme working environments. [ABSTRACT FROM AUTHOR]

Herein, a facile, catalyst-free, and dry topochemical transformation strategy for transforming the Bi2S3 nanowires to the Bi2Se3 nanowires, which has been realized through an atmospheric pressure high-temperature selenization treatment, has been developed. The complete topochemical transformation has been verified by combining x-ray diffraction, Raman spectroscopy, energy dispersive spectrometer, x-ray photoelectron spectroscopy, transmission electron microscopy, and selected area electron diffraction measurements. Systematical optical characterizations, including polarization-resolved optical microscopy images and polarization-dependent Raman spectra, have revealed the strong anisotropy of the Bi2Se3 nanowires. Furthermore, finite-different time-domain simulations have consolidated that the Bi2Se3 nanowires possess highly anisotropic absorption cross sections across the ultraviolet to far infrared spectral range, laying a solid foundation for the realization of ultra-broadband polarized optoelectronic applications. On the whole, this pioneering study depicts a unique avenue for topological material design accompanied with the integration of additional functionalities beyond the intrinsic counterparts, opening up an attractive research field for polarized photonics and optoelectronics. [ABSTRACT FROM AUTHOR]

Ultrasensitive photodetectors with polarization angle recognition have broad applications in both civilian and military domains. The emerging 2D materials with in‐plane anisotropy offer promising platforms for realizing these applications, owing to their intriguing properties. However, the lack of an effective photoconductivity gain mechanism and the low photocurrent anisotropic ratio have made it challenging to achieve digital output of polarization information. Herein, a gate voltage‐dependent phototransistor based on ReSe2/WSe2 out‐of‐plane heterostructure is proposed. Attributed to sophisticated band alignment engineering, the device exhibits remarkable photoresponse characteristics and polarization sensitivity, including an outstanding responsivity of 2.29 × 104 A W−1, an extraordinary detectivity of 5.65 × 1013 Jones, a prompt rise/decay time of 197/182 µs, as well as a high photocurrent anisotropic ratio of 10.9. Based on these features, the device is integrated into a polarization recognition system, which accurately identifies the polarization angle of the incident light and displays it. These results demonstrate the strong potential of the ReSe2/WSe2 device for future applications in polarization optical communication and logic circuits. [ABSTRACT FROM AUTHOR]

Construction of heterostructures has provided a tremendous degree of freedom to integrate, exert, and extend the features of various semiconductors, thereby opening up distinctive opportunities for the upcoming modern optoelectronics. The abundant physical properties and dangling-bond-free interface have enabled 2D layered materials serving as magical "Lego blocks" for building van der Waals heterostructures, which bring about superior contact quality (atomically sharp and distortionless) and the combination of functional units with various merits. Therefore, these heterostructures have been the focus of intensive research in the past decade. This Tutorial begins with a variety of strategies for fabricating van der Waals heterojunctions, categorized into the transfer-stacking method and in situ growth assembly method. Then, the techniques commonly exploited for characterizing the structure, morphology, band alignment, interlayer coupling, and dynamics of photocarriers of van der Waals heterojunctions are summarized, including Raman spectroscopy, photoluminescence spectroscopy, atomic force microscopy, conductive atomic force microscopy, Kelvin probe force microscope, ultraviolet photoelectron spectroscopy, transfer characteristic analysis, scanning photocurrent microscopy, etc. Following that, the application of various van der Waals heterojunctions for diverse photoelectric detection is comprehensively overviewed. On the whole, this Tutorial has epitomized the fabrication, characterization, and photodetection application of van der Waals heterostructures, which aims to provide instructive guidance for the abecedarians in this emerging field and offer impetus of advancing this rapidly evolving domain. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) excited down‐shifting (DS) double perovskites with broad emission have potential applications in anti‐counterfeiting. However, discovering new materials and achieving multimode luminescence present significant challenges. In this work, a novel double perovskite, Cs2NaGdCl6 is synthesized, with sky‐blue self‐trapped exciton (STE) emission under UV excitation using a solvothermal method. By incorporating Er3+ ions into Cs2NaGdCl6, green DS and green up‐conversion (UC) luminescence are achieved under UV and near‐infrared (NIR) excitation. The addition of the sensitizer Yb3+ ion led to a significant enhancement of 21.5‐fold in DS red luminescence and 7.5‐fold in UC green luminescence. The color of both DS and UC luminescence in Cs2NaGdCl6:Yb3+, Er3+ is further adjusted from green‐dominated to red‐dominated, due to the cross‐relaxation process between Er3+ and Yb3+, Er3+ and Er3+, respectively. The combination of UC and DS luminescence, along with the ability to modulate emission color in rare‐earth‐based materials, opens new possibilities for high security anti‐counterfeiting applications. [ABSTRACT FROM AUTHOR]

The emergence of graphene has opened the prelude of extensive research on 2D layered materials. Especially, the diverse crystal structures and exceptional physical properties of multielement van der Waals semiconductors have provided a brand‐new platform for the implementation of novel optoelectronic devices. In this study, for the first time, the optoelectronic properties of a newly emerged quaternary van der Waals semiconductor, namely silver indium phosphorus sulfide (AgInP2S6), have been systematically investigated. It is revealed that the AgInP2S6 photodetector exhibits a fast response rate with the response/recovery time down to ≈1/2 ms. In addition, the AgInP2S6 device demonstrates stable photoswitching operation even under a high working temperature of up to 160 °C in the ambient environment without using any specific protection means, and the photoswitching characteristic is also well reserved after a 10‐h continuous heating at 150 °C in air. Profiting from the strong immunity to environmental thermal disturbance, a proof‐of‐concept high‐temperature optical communication application is demonstrated. In conclusion, this study provides an intriguing paradigm for the realization of the next‐generation optoelectronic devices against extreme working circumstances, which contributes to further broadening the scope of application of 2D material photodetectors in the upcoming future (e.g., space communication and tracking). [ABSTRACT FROM AUTHOR]

Lead-based metal halides are widely investigated and applied in many fields such as light emitting diodes (LEDs), photovoltaic devices, sensors, and solar cells for their superior optical properties. However, the problem of poor stability hinders their further commercial applications. Herein, we report new all-inorganic zero-dimensional (0D) Sb3+-doped (NH4)4CdCl6 halides with highly efficient emission and stability. Under UV excitation, the emission efficiency of pristine (NH4)4CdCl6 is extremely low. However, with the introduction of optically active Sb3+, the doped (NH4)4CdCl6 showed a bright orange-yellow emission centered at 570 nm, and photoluminescence quantum yield (PLQY) reached up to 62%, which can be attributed to the unique "host–guest" structure of the 0D metal halides. By maintaining the structure type, warm white light could be tuned by A-site Rb alloying, and a PLQY of 71% could be achieved. This work is aimed to explore the emission mechanism of Sb3+ doped Cd-based metal halides, which are promising and efficient photoelectric materials with emission of Sb3+ triplet states. In addition, this research explored the structural diversity of 0D metal halides, providing design principles for warm white LEDs. [ABSTRACT FROM AUTHOR]