Organometallically Anisotropic Growth of Ultralong Sb₂Se₃ Nanowires with Highly Enhanced Photothermal Response

Ultralong orthorhombic Sb₂Se₃ nanowires have been successfully fabricated via an alternative facile organometallic synthetic route from the reaction of triphenylantimony­(III) with dibenzyldiselenide in oleylamine at 180–240 °C without any other additives. The formation and growth mechanism of the Sb₂Se₃ nanowires is intensively investigated, and it is found that the anisotropic growth of the nanowires with almost constant diameters is resulted from the synergistic effects of the intrinsic property of the orthorhombic crystal structure and the weak binding assistance of oleylamine, and the length of the nanowires can be elongated easily by increasing reaction time in the synthetic route. Moreover, the photothermal response of the Sb₂Se₃ nanowires is first evaluated under illumination of UV light (320–390 nm), and it is especially noted that the Sb₂Se₃ nanowires exhibit highly enhanced photothermal responses (more than two times the intensity) as compared to the bulk Sb₂Se₃. In addition, the Sb₂Se₃ nanowires show excellent light-to-heat performance, which is superior to that of the nanostructured titanium dioxide and silicon powder under the same conditions

Effective Synthesis of Pb₅S₂I₆ Crystals at Low Temperature for Fabrication of a High Performance Photodetector

Sulfoiodide crystals possess promising properties and functionalities that would be used for technical applications in many areas. In this work, rod-like lead sulfoiodide (Pb₅S₂I₆) crystals with a length of about 3 mm have been fabricated via a rapid hydrothermal process at a temperature down to 160 °C for 10 h with the assistance of acid media (hydrochloride acid). Meanwhile, the structure of Pb₅S₂I₆ was characterized, and the optical property of Pb₅S₂I₆ was measured and investigated based on density functional theory calculations. In addition, an individual Pb₅S₂I₆ crystal based photodetector was first constructed on SiO₂/Si substrate, which sensitively responds to stimulated sunlight especially in the visible region with high responsivity (0.567 mA W^–1), high detectivity (2.69 × 10⁹ Jones), and high photoswitching ratio (up to 650). And also, the device presents a short rise/decay time of less than 0.2 s and low noise equivalent power (4.08 × 10^–13 W Hz^–1/2)

Organometallic Synthesis, Structure Determination, Shape Evolution, and Formation Mechanism of Hexapod-like Ternary PbSe_<i>x</i>S_1–<i>x</i> Nanostructures with Tunable Compositions

The fabrication of hexapod-like ternary PbSe_<i>x</i>S_1–<i>x</i> nanostructures has been reported via an alternative organometallic route from reaction of Pb­(II) salt with triphenylphosphine selenide (Ph₃PSe) and dibenzyl disulfide (DBDS) in dibenzylamine (DBA) with addition of oleic acid (OA) at 260 °C. The shape, structure, and composition of the nanostructured hexapods are investigated and determined by techniques of XRD, SEM, TEM, Raman, HRTEM, SAED, XPS, EDX, and HAADF-STEM, and the obtained ternary nanostructured hexapods are of typical rock salt phase with Pb-rich features without phase separation, and their compositions could be systematically regulated by facile variations of reaction parameters. Investigations reveal that the successful fabrication of the ternary hexapods with tunable compositions is resulted from the effective selection of Se and S sources of Ph₃PSe and DBDS that have similar reactivity in the current reaction system along with small lattice mismatch between the two end members of PbSe and PbS. Generally, the relations between the composition and lattice parameters for the ternary nanostructures obtained in DBA with varied addition of OA exhibit linear slops that are consistent well with Vegard’s law. Interestingly, intensive investigations show that the nanostructures are mainly gradiently alloyed nanostructures with somewhat chalcogen–element segregations or disorders rather than homogeneously alloyed solid-state solutions due to kinetic limitation for short reaction time even though thermodynamics is feasible in the system, and also, high concentration of S element in the feedstocks tends to relative high density of disorders in the ternary nanostructures. Based on the revealing of the formation mechanism for the nanostructures with varied microstructures, the ternary PbSe_<i>x</i>S_1–<i>x</i> hexapods can be tuned from gradient alloys with segregations to approximately homogeneous via enlongating reaction time. In addition, the photolysis of the nanostructures to lead oxysulfate and oxyselenate species is evidenced at ambient condition via Raman detection although they are stable at −190 °C

Organometallic-Route Synthesis, Controllable Growth, Mechanism Investigation, and Surface Feature of PbSe Nanostructures with Tunable Shapes

Lead selenide (PbSe) nanostructures with well-defined star-shaped morphology are successfully fabricated via a facile organometallic synthetic route from the reaction of tetraphenyl lead (Ph₄Pb) with triphenylphosphine selenide (Ph₃PSe) in dibenzylamine (DBA) with the assistance of oleic acid (OA) and oleylamine (OAm) at 220 °C for 30 min. The structure and shape of the nanocrystals are investigated by techniques of XRD, SEM, TEM, HRTEM, SAED, and EDX, and it is interesting that the obtained PbSe nanostars present Pb-rich features, although the PbSe nanostars are still in typical rock salt phase. Experimental investigations and ATR-FTIR studies demonstrate that the media of DBA, OA, and OAm with an order OA > DAB > OAm play important roles in the growth of the PbSe nanostars with well-defined shapes because the media not only serve as solvents but capping materials. The synergetic effects of the media are also favorable for the growth of PbSe nanocrystals with the well-defined star-shaped morphologies in the current reaction system. Meanwhile, varied PbSe nanostructures with cubic, side-cut cubic, and octahedral shapes can be fabricated by regulating the relevant reaction conditions, and all of these nanostructures prepared in the procedures demonstrate Pb-rich features due to the selective capping effects of the media to the exposed Pb­(II) ions. It is confirmed that the specific shape and geometry of the nanostructures can be tuned by controlling the exposed crystal surfaces and/or the corresponding compositions via the variation of reaction conditions in the media