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Eutectic gallium‐indium (EGaIn) liquid metal droplets have been considered as a suitable platform for producing customized 3D composites with functional nanomaterials owing to their soft and highly reductive surface. Herein, the synthesis of a 3D plasmonic oxide framework (POF) is reported by incorporating the ultra‐thin angstrom‐scale‐porous hexagonal molybdenum oxide (h‐MoO3) onto the spherical EGaIn nanodroplets through ultrasonication. Simultaneously, a large number of oxygen vacancies form in h‐MoO3, boosting its free charge carrier concentration and therefore generating a broad surface plasmon resonance across the whole visible light spectrum. The plasmonic chemical sensing properties of the POF is investigated by the surface‐enhanced Raman scattering detection of rhodamine 6G (R6G) at 532 nm, in which the minimum detectable concentration is 10−8m and the enhancement factor reached up to 6.14 × 106. The extended optical absorption of the POF also allowed the efficient degradation of the R6G dye under the excitation of ultraviolet‐filtered simulated solar light. Furthermore, the POF exhibits remarkable photocurrent responses towards the entire visible light region with the maximum response of ≈1588 A W−1 at 455 nm. This work demonstrates the great potential of the liquid metal‐based POFs for high‐performance sensing, catalytic, and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Chalcohalide semiconductors are an emergent class of materials for optoelectronics. Here, the first work on BiSI chalcohalide thin film photodetectors (PDs) is presented. An entirely new method for the fabrication of bismuth chalcohalide thin films (BiOI and BiSI) is developed. This method circumvents the use of any ligands or counter ions during fabrication and provides highly pure thin films free of carbon residues and other contaminants. When integrated into lithographically patterned lateral PDs these BiSI thin films show outstanding performances and high stability. The direct ≈1.55 eV bandgap of BiSI perfectly accommodates optical sensing over the full visible spectrum. The responsivity (R) of the BiSI PDs reaches 62.1 A W−1, which is the best value reported to date across chalcohalide materials of any type. The BiSI PDs display remarkable sensitivity to low light levels, supporting a broad operational detectivity ≈1012 Jones over four decades in light intensity, with a peak specific detectivity (D*) of 2.01 × 1013 Jones. The dynamics of photocurrent generation are demonstrated to be dominated by photoconductive gain. These results cement BiSI as an exciting candidate for high performance photodetector applications and encourage ongoing work in BiSX (X = Cl, Br, I) materials for optoelectronics. [ABSTRACT FROM AUTHOR]

Atomically thin 2D materials are highly sought for high‐performance electronic and optoelectronic devices. Despite being a widely recognized functional material for a plethora of applications, ultra‐thin nanosheets of zinc oxide (ZnO) at a millimeter‐scale for developing high‐performance electronic/optoelectronic devices have not been reported. This has prevented the exploration of electronic and optical properties of ZnO when it is only a few atoms thick. Here, a liquid metal exfoliation technique is used that takes advantage of the van der Waals forces between the interfacial oxide and the chosen substrate to obtain ZnO nanosheets with lateral dimensions in the millimeter scale and thickness down to 5 nm. Their suitability for applications is shown by demonstrating a visible‐blind photodetector with high figures of merit as compared to other ZnO morphologies. At extremely low operating bias of 50 mV and low optical intensity of 0.5 mW cm−2, the ZnO photodetector demonstrates an external quantum efficiency (EQE), responsivity (R), and detectivity (D*) of 4.3 × 103%, 12.64 A W−1, and 5.81 × 1015 Jones at a wavelength of 365 nm. The trap‐mediated photoresponse in the ZnO nanosheets is further utilized to demonstrate optoelectronic synapses. Versatile synaptic functions of the nervous systems are optically emulated with the ultra‐thin ZnO nanosheets. [ABSTRACT FROM AUTHOR]